Patent Publication Number: US-2016235844-A1

Title: Methods of treating neuroendocrine tumors using frizzled-binding agents

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 14/059,918, filed Oct. 22, 2013, which claims priority benefit of U.S. Provisional Application No. 61/717,294, filed Oct. 23, 2012, and U.S. Provisional Application No. 61/760,529, filed Feb. 4, 2013, each of which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The field of this invention generally relates to methods of treating neuroendocrine tumors. In one embodiment, the method comprises administering to a subject in need thereof a therapeutically effective dose of a Wnt antagonist. 
     REFERENCE TO SEQUENCE LISTING SUBMITTED ELECTRONICALLY VIA EFS-WEB 
     The content of the electronically submitted sequence listing (Name: 2293_0950003_SeqListing_ST25.txt; Size: 190 kilobytes; and Date of Creation: Jan. 6, 2016) is herein incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     Cancer is one of the leading causes of death in the developed world, with over one million people diagnosed with cancer and 500,000 deaths per year in the United States alone. Overall it is estimated that more than 1 in 3 people will develop some form of cancer during their lifetime. There are more than 200 different types of cancer, four of which—breast, lung, colorectal, and prostate—account for over half of all new cases (Jemal et al., 2003,  Cancer J. Clin.  53:5-26). 
     The Wnt signaling pathway has been identified as a potential target for cancer therapy. The Wnt signaling pathway is one of several critical regulators of embryonic pattern formation, post-embryonic tissue maintenance, and stem cell biology. More specifically, Wnt signaling plays an important role in the generation of cell polarity and cell fate specification including self-renewal by stem cell populations. Unregulated activation of the Wnt pathway is associated with numerous human cancers where it can alter the developmental fate of tumor cells to maintain them in an undifferentiated and proliferative state. Thus carcinogenesis can proceed by usurping homeostatic mechanisms controlling normal development and tissue repair by stem cells (reviewed in Reya &amp; Clevers, 2005,  Nature  434:843; Beachy et al., 2004,  Nature  432:324). 
     The Wnt signaling pathway was first elucidated in the  Drosophila  developmental mutant wingless (wg) and from the murine proto-oncogene int-1, now Wnt1 (Nusse &amp; Varmus, 1982,  Cell  31:99-109; Van Ooyen &amp; Nusse, 1984,  Cell  39:233-40; Cabrera et al., 1987,  Cell  50:659-63; Rijsewijk et al., 1987,  Cell  50:649-57). Wnt genes encode secreted lipid-modified glycoproteins of which 19 have been identified in mammals. These secreted ligands activate a receptor complex consisting of a Frizzled (Fzd) receptor family member and low-density lipoprotein (LDL) receptor-related protein 5 or 6 (LPRS/6). The Fzd receptors are seven transmembrane domain proteins of the G-protein coupled receptor (GPCR) superfamily and contain a large extracellular N-terminal ligand binding domain with 10 conserved cysteines, known as a cysteine-rich domain (CRD) or Fri domain. There are ten human FZD receptors: FZD1-10. Different Fzd CRDs have different binding affinities for specific Wnts (Wu &amp; Nusse, 2002,  J. Biol. Chem.  277:41762-9), and Fzd receptors have been grouped into those that activate the canonical β-catenin pathway and those that activate non-canonical pathways described below (Miller et al., 1999,  Oncogene  18:7860-72). To form the receptor complex that binds the FZD ligands, FZD receptors interact with LRP5/6, single pass transmembrane proteins with four extracellular EGF-like domains separated by six YWTD amino acid repeats (Johnson et al., 2004,  J. Bone Mineral Res.  19:1749). 
     The Wnt/beta-catenin signaling pathway has been implicated in the development of gastrointestinal carcinoid tumors. Fujimori et al.,  Cancer Res.  61(18): 6656-9 (2001). Nuclear translocation of β-catenin protein but absence of β-catenin and APC mutation in gastrointestinal carcinoid tumor has also been observed. Su et al.,  Ann. Surg. Oncol.  13(12): 1604-9 (2006). 72 cases of gastrointestinal carcinoid tumor were investigated both immunohistochemically and by direct sequencing of beta-catenin. Accumulation of beta-catenin in the cytoplasm and/or nucleus was observed in 57 cases (79.2%). Mutations were also detected in exon 3 of beta-catenin in 27 cases (37.5%), and in APC in one case (1.4%). Su et al. also reported the investigation of 91 gastrointestinal carcinoid tumors and, for comparison, 26 extragastrointestinal carcinoid tumors by immunohistochemical detection of beta-catenin protein and direct sequencing of exon 3 of the beta-catenin gene and exon 15 of the APC gene. Cytoplasmic accumulation and/or nuclear translocation of beta-catenin were found in 27 gastrointestinal carcinoid tumors (29.7%) but not in any extragastrointestinal carcinoid tumors. Neither beta-catenin nor APC gene mutation was detected in any of the cases with nuclear expression of beta-catenin. 
     SUMMARY OF THE INVENTION 
     The present invention provides methods of treating a neuroendocrine tumor. Thus in one aspect, the invention provides methods of inhibiting the growth of a neuroendocrine tumor, comprising contacting the neuroendocrine tumor with an effective amount of a Wnt antagonist. In another aspect, the invention provides methods of inhibiting the proliferation of neuroendocrine tumor cells, comprising contacting the neuroendocrine tumor cells with an effective amount of a Wnt antagonist. In another aspect, the invention provides methods of reducing the tumorigenicity of neuroendocrine tumor cells, comprising contacting the neuroendocrine tumor cells with an effective amount of a Wnt antagonist. In another aspect, the invention provides methods of inducing neuroendocrine tumor cells to differentiate, comprising contacting the neuroendocrine tumor cells with an effective amount of a Wnt antagonist. In another aspect, the invention provides methods of inhibiting the growth of a neuroendocrine tumor, comprising administering to a subject in need thereof a therapeutically effective amount of a Wnt antagonist. In another aspect, the invention provides methods of inhibiting the proliferation of neuroendocrine tumor cells, comprising administering to a subject in need thereof a therapeutically effective amount of a Wnt antagonist. In another aspect, the invention provides methods of treating neuroendocrine cancer, comprising administering to a subject in need thereof a therapeutically effective amount of a Wnt antagonist. In certain embodiments the subject is a human subject. 
     In certain embodiments of each of the aforementioned aspects or embodiments, as well as other aspects and/or embodiments described elsewhere herein, the neuroendocrine tumor is a low grade, medium grade, or high grade neuroendocrine tumor. In further embodiments, the neuroendocrine tumor is a functional neuroendocrine tumor or a non-functional neuroendocrine tumor. In further embodiments, the neuroendocrine tumor is selected from the group consisting of gastroenteropancreatic neuroendocrine tumor, carcinoid tumor, pheochromocytoma, paraganglioma, medullary thyroid cancer, pulmonary neuroendocrine tumor and thymic neuroendocrine tumor. In further embodiments, the neuroendocrine tumor is a carcinoid tumor or a pancreatic neuroendocrine tumor. 
     In certain embodiments of each of the aforementioned aspects or embodiments, as well as other aspects and/or embodiments described elsewhere herein, the Wnt antagonist is an antibody. In further embodiments, the Wnt antagonist is an antibody that specifically binds to at least one human Wnt. In further embodiments, the Wnt antagonist is an antibody that specifically binds to at least one human frizzled receptor (FZD). In further embodiments, the Wnt antagonist is a soluble FZD receptor. 
     In certain embodiments of each of the aforementioned aspects or embodiments, as well as other aspects and/or embodiments described elsewhere herein, the Wnt antagonist is an antibody that specifically binds to at least one human frizzled receptor (FZD). In further embodiments, the antibody specifically binds to the extracellular domain of at least one human FZD. In further embodiments, the antibody specifically binds to a human FZD selected from the group consisting of FZD1, FZD2, FZD5, FZD7, and FZD8. In further embodiments, the antibody specifically binds to FZD7. In further embodiments, the antibody specifically binds to more than one human FZD. In further embodiments, the antibody specifically binds to three or more human FZD selected from the group consisting of FZD1, FZD2, FZD5, FZD7, and FZD8. In further embodiments, the antibody specifically binds to more than one human FZD selected from the group consisting of FZD1, FZD2, FZD5, FZD7, and FZD8. In further embodiments, the antibody specifically binds to FZD1, FZD2, FZD5, FZD7, and FZD8. 
     In further embodiments, the antibody blocks ligand binding to FZD. In further embodiments, the antibody blocks Wnt binding to FZD. In further embodiments, the antibody blocks the activation of FZD. 
     In further embodiments, the antibody comprises: (1) a heavy chain CDR1 comprising GFTFSHYTLS (SEQ ID NO:31), a heavy chain CDR2 comprising VISGDGSYTYYADSVKG (SEQ ID NO:32), and a heavy chain CDR3 comprising NFIKYVFAN (SEQ ID NO:33); and/or (2) (a) a light chain CDR1 comprising SGDNIGSFYVH (SEQ ID NO:34), a light chain CDR2 comprising DKSNRPSG (SEQ ID NO:35), and a light chain CDR3 comprising QSYANTLSL (SEQ ID NO:36); or (b) a light chain CDR1 comprising SGDKLGKKYAS (SEQ ID NO:41), a light chain CDR2 comprising EKDNRPSG (SEQ ID NO:42), and a light chain CDR3 comprising SSFAGNSLE (SEQ ID NO:43). In further embodiments, the antibody comprises: a VH comprising the amino acid sequence of SEQ ID NO:37; and/or a VL comprising the amino acid sequence of SEQ ID NO:38 or 44. In further embodiments, the antibody comprises: a heavy chain comprising the amino acid sequence of SEQ ID NO:39; and/or a light chain comprising the amino acid sequence of SEQ ID NO:40 or 45. 
     In further embodiments, the antibody is a monoclonal antibody. In further embodiments, the antibody is a recombinant antibody, a chimeric antibody, a humanized antibody, a human antibody, or an antibody fragment. In further embodiments, the antibody is a monospecific antibody or a bispecific antibody. In further embodiments, the antibody is an IgA, IgD, IgE, IgG or IgM antibody. In further embodiments, the antibody is an IgG1 or IgG2 antibody. 
     In further embodiments, the Wnt antagonist is OMP-18R5 (also known as “vantictumab”). 
     In certain embodiments of each of the aforementioned aspects or embodiments, as well as other aspects and/or embodiments described elsewhere herein, the Wnt antagonist is a soluble FZD receptor. In further embodiments, the soluble FZD receptor binds to Wnt. In further embodiments, the soluble receptor comprises a fragment of the extracellular domain of a human FZD receptor. In further embodiments, the fragment of the extracellular domain of the human FZD receptor comprises the Fri domain of the human FZD receptor. 
     In further embodiments, the human FZD receptor is selected from the group consisting of FZD4, FZD5, and FZD8. In further embodiments, the human FZD receptor is FZD8. In further embodiments, the FZD8 Fri domain comprises the amino acid sequence of SEQ ID NO:28. 
     In further embodiments, the soluble receptor further comprises a human Fc domain. In further embodiments, the human Fc domain comprises the amino acid sequence of SEQ ID NO:95. 
     In further embodiments, the Wnt antagonist is OMP-54F28. 
     In certain embodiments of each of the aforementioned aspects or embodiments, as well as other aspects and/or embodiments described elsewhere herein, the methods further comprise contacting the tumor or tumor cells with a second therapeutic agent, or administering a second therapeutic agent to the subject. In further embodiments, the second therapeutic agent is a chemotherapeutic agent. In further embodiments, the second therapeutic agent is a kinase inhibitor, somatostatin analog or an mTOR pathway inhibitor. In further embodiments, the second therapeutic agent is sunitinib, octreotide, or everolimus. In further embodiments, the second therapeutic agent is an antibody. In further embodiments, the second therapeutic agent is an angiogenesis inhibitor. 
     Where aspects or embodiments of the invention are described in terms of a Markush group or other grouping of alternatives, the present invention encompasses not only the entire group listed as a whole, but each member of the group individually and all possible subgroups of the main group, but also the main group absent one or more of the group members. The present invention also envisages the explicit exclusion of one or more of any of the group members in the claimed invention. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         FIGS. 1A-C . Effect of Wnt inhibitors on neuroendocrine tumor growth. The size of tumor lesions in a pancreatic neuroendocrine tumor patient was reduced following the administration of the OMP-18R5 anti-FZD7 antibody. ( FIG. 1A ) Radiographic assessment of the size of target and non-target lesions at day 56 and day 112 of OMP-18R5 anti-FZD7 antibody treatment. BL denotes the baseline size of the lesions before the administration of OMP-18R5. ( FIG. 1B ) CT image of the tumor lesions before (Baseline) and after 112 days of OMP-18R5 administration. ( FIG. 1C ) CT image of the tumor lesions before (Baseline) and after 112 days of OMP-18R5 administration. The tumor lesion at day 112 displays radiologic signs of calcification. 
         FIG. 2 . Days on study for patients on OMP-18R5 Phase 1a study. The number of days each of the patients (n=18) enrolled in the OMP-18R5 Phase 1a study has stayed on the study as of Jan. 25, 2013, is shown graphically in the figure. Arrows indicate the patients who remained on the study as of Jan. 25, 2013. The vertical lines indicate dates of tumor assessments on the study. The neuroendocrine tumor patients are patients 003 (Patient 3 in Example 1), 010 (Patient 10 in Example 1), and 012 (Patient 12 in Example 1). The other patients on the study had other types of advanced solid tumors such as colorectal cancer, breast cancer, melanoma, and pancreatic cancer. 
         FIG. 3 . Days on study for patients with neuroendocrine tumors on OMP-18R5 Phase la study were compared to days on treatment with prior regimens. Patient 10, a 69-year-old woman with neuroendocrine tumor of the pancreas, continues on study with stable disease for 279 days (as of Jan. 25, 2013). Patient 12, a 77-year-old woman with carcinoid, continues on study with stable disease for 210 days (as of Jan. 25, 2013). 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention provides methods of inhibiting the growth of a neuroendocrine tumor, methods of inhibiting proliferation of neuroendocrine tumor cells, methods of treating a neuroendocrine cancer, methods of inhibiting neuroendocrine tumor metastases, methods of inducing neuroendocrine tumor cell differentiation, methods of reducing tumorgenicity of neuroendocrine tumor cells and methods of reducing the frequency of cancer stem cells or tumor initiating cells in a neuroendocrine tumor. In some embodiments, the methods provided herein comprise administering a Wnt antagonist to a subject. In some embodiments, the Wnt antagonist is a FZD-binding agent that specifically binds to one or more human FZD receptors. In further embodiments, the FZD-binding agent is an antibody that specifically binds to one or binds to one or more human FZD receptors. In some embodiments, the Wnt antagonist is a Wnt binding agent that specifically binds to one or more human Wnt polypeptide. In some embodiments, the Wnt binding agent is a soluble FZD receptor. In some embodiments, the Wnt binding agent is an anti-Wnt antibody. 
     Human patients with late stage neuroendocrine tumors were treated with low doses of the 
     OMP-18R5 anti-FZD antibody in the context of a Phase 1 clinical trial for patients with late stage solid tumors. (Example 1.) Surprisingly, one of the patients (a patient having a pancreatic neuroendocrine tumor) showed a reduction in tumor lesion size after 112 days of treatment with OMP-18R5 and remained on study without evidence of any progression of disease for 279 days (as of Jan. 25, 2013). Additionally, new calcification was seen in one of the patient&#39;s lesions which may represent possible signs of tumor cell necrosis and/or differentiation. In addition, two patients with neuroendocrine tumors having carcinoid histology were also able to stay on the study for surprisingly long periods of time with stable disease during treatment with OMP-18R5. (Example 1.) Collectively, these results suggest that OMP-18R5 may be particularly useful in the treatment of a variety of neuroendocrine tumors. 
     1. Definitions 
     To facilitate an understanding of the present invention, a number of terms and phrases are defined below. 
     The term “antagonist” is used herein to include any molecule that partially or fully blocks, inhibits, or neutralizes the expression of or the biological activity of a protein, (e.g., a cancer stem cell marker). The blocking, inhibiting, and/or neutralizing of biological activity includes, but is not limited to, inhibition of tumor growth. The term “antagonist” also includes any molecule that partially or fully blocks, inhibits, or neutralizes a biological activity of the Wnt pathway. The term “Wnt antagonist” is used herein to include any molecule that partially or fully blocks, inhibits or neutralizes the signaling of the Wnt pathway (e.g., canonical Wnt signaling), or partially or fully blocks, inhibits or neutralizes a biological activity of a component of the Wnt pathway. Wnt antagonists do not necessarily bind Wnt. For instance, in certain embodiments Wnt antagonists bind one or more other components of the Wnt pathway such as one or more FZD receptors. Suitable Wnt antagonist molecules include, but are not limited to, fragments and/or amino acid sequence variants of native FZD receptor proteins including soluble FZD receptors, as well as derivatives of soluble Frizzled-related proteins (SFRPs), and derivatives of Ror proteins. Suitable Wnt antagonist molecules further include, but are not limited to, antibodies that specifically bind to one or more FZD receptors and antibodies that specifically bind to one or more Wnt polypeptide. Soluble SFRP and Ror receptors are described in US Pat. Appl. Pub. No. 2011/0305695, which is herein incorporated by reference. 
     In vivo and in vitro assays for determining whether an agent (e.g., soluble FZD receptor or anti-FZD antibody) inhibits Wnt signaling are known in the art. For example, cell-based, luciferase reporter assays utilizing a TCF/Luc reporter vector containing multiple copies of the TCF-binding domain upstream of a firefly luciferase reporter gene may be used to measure canonical Wnt signaling levels in vitro (Gazit et al., 1999,  Oncogene  18; 5959-66). The level of Wnt signaling in the presence of one or more Wnts (e.g., Wnt(s) expressed by transfected cells or provided by Wnt-conditioned media) with the agent present is compared to the level of signaling without the agent present. In addition to the TCF/luc reporter assay, the effect of an agent (e.g., soluble FZD receptor or anti-FZD antibody) on canonical Wnt signaling can be measured in vitro or in vivo by measuring the effect of the agent on the level of expression of beta-catenin regulated genes, such as c-myc (He et al.,  Science,  281:1509-12 (1998)), cyclin D1 (Tetsu et al.,  Nature,  398:422-6 (1999)) and/or fibronectin (Gradl et al.  Mol. Cell Biol.,  19:5576-87 (1999)). In certain embodiments, the effect of the agent on Wnt signaling can also be assessed by measuring the effect of the agent on the phosphorylation state of Dishevelled-1, Dishevelled-2, Dishevelled-3, LRP5, LRP6, and/or beta-catenin. In still further embodiments, the effect of the agent on Wnt signaling is determined by assessing the impact of the agent on the expression level of one or more genes in a Wnt signature. Non-limiting examples of the use of such assays to assess inhibition of canonical Wnt signaling are disclosed in U.S. Pat. Appl. Pub. No. 2012/0027778, which is incorporated by reference herein in its entirety. 
     As used herein the term “soluble receptor” refers to an amino-terminal extracellular fragment of a receptor protein preceding the transmembrane domain that can be secreted from a cell in soluble form. In some embodiments, the receptor protein is a FZD receptor. In some embodiments, the receptor protein is the ROR1 or ROR2 receptor. In certain embodiments, the soluble receptor is linked in-frame with a polypeptide that increases the half-life of the soluble receptor. In certain embodiments, the polypeptide that increases half-life is a human Fc domain. 
     As used herein the term “FZD soluble receptor” refers to an amino-terminal extracellular fragment of a human FZD receptor protein preceding the transmembrane domain of the receptor that can be secreted from a cell in soluble form. FZD soluble receptors comprising the entire amino-terminal extracellular domain (ECD) (referred to herein as “FZD ECD”) as well as smaller fragments of the ECD are envisioned. FZD soluble receptors comprising the Fri domain (referred to herein as “FZD Fri”) are also disclosed. Soluble FZD receptors are described in US Pat. Appl. Pub. No. 2011/0305695, which is herein incorporated by reference. 
     FZD Fri soluble receptors can demonstrate altered biological activity, (e.g., increased protein half-life) compared to soluble receptors comprising the entire FZD ECD. Protein half-life can be further increased by covalent modification with polyethylene glycol (PEG) or polyethylene oxide (PEO). FZD soluble receptors include FZD ECD or Fri domains linked in-frame to other functional and structural proteins including, but not limited to, a human Fc region (e.g., human Fc derived from immunoglobulins IgG1, IgG2, IgG3, IgG4, IgA1, IgA2, IgD, IgE, or IgM); protein tags (e.g., myc, FLAG, GST); other endogenous proteins or protein fragments; or any other useful protein sequence including any linker region between a FZD ECD or Fri domain and a linked protein. In certain embodiments, the Fri domain of a FZD receptor is directly linked to a human Fc region. In certain embodiments, the Fri domain of a FZD receptor is linked to human IgG1 Fc (referred to herein as “FZD Fri.Fc,” e.g. “FZD8 Fri.Fc”). In some embodiments, the Fri domain of a FZD receptor is linked to a human Fc region with a peptide linker. FZD soluble receptors also include variant proteins comprising amino acid insertions, deletions, substitutions, and/or conservative substitutions. 
     As used herein, the term “linker” or “linker region” refers to a linker inserted between a first polypeptide (e.g., a FZD component) and a second polypeptide (e.g., an Fc region). In some embodiments, the linker is a peptide linker. Linkers should not adversely affect the expression, secretion, or bioactivity of the polypeptides. Preferably, linkers are not antigenic and do not elicit an immune response. 
     The term “antibody” means an immunoglobulin molecule that recognizes and specifically binds to a target, such as a protein, polypeptide, peptide, carbohydrate, polynucleotide, lipid, or combinations of the foregoing through at least one antigen recognition site within the variable region of the immunoglobulin molecule. As used herein, the term “antibody” encompasses intact polyclonal antibodies, intact monoclonal antibodies, antibody fragments (such as Fab, Fab′, F(ab′)2, and Fv fragments), single chain Fv (scFv) mutants, multispecific antibodies such as bispecific antibodies generated from at least two intact antibodies, chimeric antibodies, humanized antibodies, human antibodies, fusion proteins comprising an antigen determination portion of an antibody, and any other modified immunoglobulin molecule comprising an antigen recognition site so long as the antibodies exhibit the desired biological activity. An antibody can be of any the five major classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM, or subclasses (isotypes) thereof (e.g. IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2), based on the identity of their heavy-chain constant domains referred to as alpha, delta, epsilon, gamma, and mu, respectively. The different classes of immunoglobulins have different and well known subunit structures and three-dimensional configurations. Antibodies can be naked or conjugated to other molecules such as toxins, radioisotopes, etc. 
     The term “antibody fragment” refers to a portion of an intact antibody and refers to the antigenic determining variable regions of an intact antibody. Examples of antibody fragments include, but are not limited to Fab, Fab′, F(ab′)2, and Fv fragments, linear antibodies, single chain antibodies, and multispecific antibodies formed from antibody fragments. 
     A “monoclonal antibody” refers to a homogeneous antibody population involved in the highly specific recognition and binding of a single antigenic determinant, or epitope. This is in contrast to polyclonal antibodies that typically include different antibodies directed against different antigenic determinants. The term “monoclonal antibody” encompasses both intact and full-length monoclonal antibodies as well as antibody fragments (such as Fab, Fab′, F(ab′)2, Fv), single chain (scFv) mutants, fusion proteins comprising an antibody portion, and any other modified immunoglobulin molecule comprising an antigen recognition site. Furthermore, “monoclonal antibody” refers to such antibodies made in any number of manners including but not limited to by hybridoma, phage selection, recombinant expression, and transgenic animals. 
     The term “humanized antibody” refers to forms of non-human (e.g. murine) antibodies that are specific immunoglobulin chains, chimeric immunoglobulins, or fragments thereof that contain minimal non-human (e.g., murine) sequences. Typically, humanized antibodies are human immunoglobulins in which residues from the complementary determining region (CDR) are replaced by residues from the CDR of a non-human species (e.g. mouse, rat, rabbit, hamster) that have the desired specificity, affinity, and capability (Jones et al., 1986,  Nature,  321:522-525; Riechmann et al., 1988,  Nature,  332:323-327; Verhoeyen et al., 1988,  Science,  239:1534-1536). In some instances, the Fv framework region (FR) residues of a human immunoglobulin are replaced with the corresponding residues in an antibody from a non-human species that has the desired specificity, affinity, and capability. The humanized antibody can be further modified by the substitution of additional residues either in the Fv framework region and/or within the replaced non-human residues to refine and optimize antibody specificity, affinity, and/or capability. In general, the humanized antibody will comprise substantially all of at least one, and typically two or three, variable domains containing all or substantially all of the CDR regions that correspond to the non-human immunoglobulin whereas all or substantially all of the FR regions are those of a human immunoglobulin consensus sequence. The humanized antibody can also comprise at least a portion of an immunoglobulin constant region or domain (Fc), typically that of a human immunoglobulin. Examples of methods used to generate humanized antibodies are described in U.S. Pat. No. 5,225,539. 
     The term “human antibody” means an antibody produced by a human or an antibody having an amino acid sequence corresponding to an antibody produced by a human made using any technique known in the art. This definition of a human antibody includes intact or full-length antibodies, fragments thereof, and/or antibodies comprising at least one human heavy and/or light chain polypeptide such as, for example, an antibody comprising murine light chain and human heavy chain polypeptides. 
     The term “epitope” or “antigenic determinant” are used interchangeably herein and refer to that portion of an antigen capable of being recognized and specifically bound by a particular antibody. When the antigen is a polypeptide, epitopes can be formed both from contiguous amino acids and noncontiguous amino acids juxtaposed by tertiary folding of a protein. Epitopes formed from contiguous amino acids are typically retained upon protein denaturing, whereas epitopes formed by tertiary folding are typically lost upon protein denaturing. An epitope typically includes at least 3, and more usually, at least 5 or 8-10 amino acids in a unique spatial conformation. 
     That a polypeptide or other agent (e.g., antibody or soluble receptor) “specifically binds” to a protein means that the polypeptide or other agent reacts or associates more frequently, more rapidly, with greater duration, with greater affinity, or with some combination of the above to the protein than with alternative substances, including unrelated proteins. In certain embodiments, “specifically binds” means, for instance, that an agent (e.g., antibody or soluble receptor) binds to a protein with a K D  of about 0.1 mM or less, but more usually less than about 1 μM. In certain embodiments, “specifically binds” means that an agent (e.g., antibody or soluble receptor) binds to a protein at times with a K D  of at least about 0.1 μM or less, at least about 0.01 μM or less, and at other times at least about 1 nM or less. Because of the sequence identity between homologous proteins in different species, specific binding can include an agent (e.g., antibody or soluble receptor) that recognizes a particular protein such as a Wnt protein or a frizzled receptor in more than one species. Likewise, because of homology between different paralogues (e.g., the different human Wnt proteins or human frizzled proteins) in certain regions of their sequences, specific binding can include a polypeptide or an agent (e.g., antibody or soluble receptor) that recognizes more than one paralogue (e.g., more than one human Wnt protein or more than one human frizzled protein). It is understood that an agent (e.g., antibody or soluble receptor) that specifically binds to a first target may or may not specifically bind to a second target. As such, “specific binding” does not necessarily require (although it can include) exclusive binding, i.e. binding to a single target. Thus, an agent (e.g., antibody or soluble receptor) may, in certain embodiments, specifically bind to more than one target (e.g., multiple different human Wnt proteins or multiple different frizzled proteins, such as FZD1, FZD2, FZD5, FZD7, and/or FZD8). In certain embodiments, the multiple targets of an antibody may be bound by the same antigen-binding site on the antibody. For example, an antibody may, in certain instances, comprise two identical antigen-binding sites, each of which specifically binds two or more human frizzled receptors (e.g., human FZD1, FZD2, FZD5, FZD7, and/or FZD8). In certain alternative embodiments, an antibody may be bispecific and comprise at least two antigen-binding sites with differing specificities. By way of non-limiting example, a bispecific antibody may comprise one antigen-binding site that recognizes an epitope on one frizzled receptor, such as human FZD5, and further comprises a second, different antigen-binding site that recognizes a different epitope on a second frizzled receptor, such as human FZD8. Generally, but not necessarily, reference to binding means specific binding. 
     The terms “cancer” and “cancerous” refer to or describe the physiological condition in mammals in which a population of cells are characterized by unregulated cell growth. The term cancer is understood to encompass Wnt-dependent cancers. Examples of cancer include, but are not limited to, carcinoma, lymphoma, blastoma, sarcoma, and leukemia. 
     “Tumor” and “neoplasm” refer to any mass of tissue that result from excessive cell growth or proliferation, either benign (noncancerous) or malignant (cancerous) including pre-cancerous lesions. 
     The terms “cancer stem cell,” “tumor stem cell,” or “solid tumor stem cell” are used interchangeably herein and refer to a population of cells from a solid tumor that: (1) have extensive proliferative capacity; (2) are capable of asymmetric cell division to generate one or more kinds of differentiated progeny with reduced proliferative or developmental potential; and (3) are capable of symmetric cell divisions for self-renewal or self-maintenance. These properties of “cancer stem cells,” “tumor stem cells,” or “solid tumor stem cells” confer on those cancer stem cells the ability to form palpable tumors upon serial transplantation into an immunocompromised mouse compared to the majority of tumor cells that fail to form tumors. Cancer stem cells undergo self-renewal versus differentiation in a chaotic manner to form tumors with abnormal cell types that can change over time as mutations occur. 
     The terms “cancer cell,” “tumor cell,” and grammatical equivalents refer to the total population of cells derived from a tumor or a pre-cancerous lesion, including both non-tumorigenic cells, which comprise the bulk of the tumor cell population, and tumorigenic stem cells (cancer stem cells). As used herein, the term “tumor cell” will be modified by the term “non-tumorigenic” when referring solely to those tumor cells lacking the capacity to renew and differentiate to distinguish those tumor cells from cancer stem cells. 
     The term “tumorigenic” refers to the functional features of a solid tumor stem cell including the properties of self-renewal (giving rise to additional tumorigenic cancer stem cells) and proliferation to generate all other tumor cells (giving rise to differentiated and thus non-tumorigenic tumor cells) that allow solid tumor stem cells to form a tumor. These properties of self-renewal and proliferation to generate all other tumor cells confer on cancer stem cells the ability to form palpable tumors upon serial transplantation into an immunocompromised mouse compared to non-tumorigenic tumor cells, which are unable to form tumors upon serial transplantation. It has been observed that non-tumorigenic tumor cells may form a tumor upon primary transplantation into an immunocompromised mouse after obtaining the tumor cells from a solid tumor, but those non-tumorigenic tumor cells do not give rise to a tumor upon serial transplantation. 
     The term “subject” refers to any animal (e.g., a mammal), including, but not limited to humans, non-human primates, rodents, and the like, which is to be the recipient of a particular treatment. Typically, the terms “subject” and “patient” are used interchangeably herein in reference to a human subject. 
     The term “therapeutically effective amount” refers to an amount of an agent (e.g., antibody, soluble receptor, polypeptide, polynucleotide, small organic molecule, or other drug) effective to “treat” a disease or disorder in a subject or mammal. In the case of cancer, the therapeutically effective amount of the agent can reduce the number of cancer cells; reduce the tumor size; inhibit or stop cancer cell infiltration into peripheral organs including, for example, the spread of cancer into soft tissue and bone; inhibit and stop tumor metastasis; inhibit and stop tumor growth; relieve to some extent one or more of the symptoms associated with the cancer; reduce morbidity and mortality; improve quality of life; decrease tumorigenicity, tumorigenic frequency, or tumorigenic capacity of a tumor; reduce the number or frequency of cancer stem cells in a tumor; differentiate tumorigenic cells to a non-tumorigenic state; or a combination of such effects. To the extent the agent prevents growth and/or kills existing cancer cells, it can be referred to as cytostatic and/or cytotoxic. 
     As used herein the term “inhibit tumor growth” refers to any mechanism by which tumor cell growth can be inhibited. In certain embodiments, tumor cell growth is inhibited by slowing proliferation of tumor cells. In certain embodiments, tumor cell growth is inhibited by halting proliferation of tumor cells. In certain embodiments, tumor cell growth is inhibited by killing tumor cells. In certain embodiments, tumor cell growth is inhibited by inducing apoptosis of tumor cells. In certain embodiments, tumor cell growth is inhibited by inducing differentiation of tumor cells. In certain embodiments, tumor cell growth is inhibited by depriving tumor cells of nutrients. In certain embodiments, tumor cell growth is inhibited by preventing migration of tumor cells. In certain embodiments, tumor cell growth is inhibited by preventing invasion of tumor cells. 
     Terms such as “treating” or “treatment” or “to treat” or “alleviating” or “to alleviate” refer to both 1) therapeutic measures that cure, slow down, lessen symptoms of, and/or halt progression of a diagnosed pathologic condition or disorder and 2) prophylactic or preventative measures that prevent and/or slow the development of a targeted pathologic condition or disorder. Thus, those in need of treatment include those already with the disorder; those prone to have the disorder; and those in whom the disorder is to be prevented. In certain embodiments, a subject is successfully “treated” for cancer according to the methods of the present invention if the patient shows one or more of the following: a reduction in the number of or complete absence of cancer cells; a reduction in the tumor size; inhibition of or an absence of cancer cell infiltration into peripheral organs including, for example, the spread of cancer into soft tissue and bone; inhibition of or an absence of tumor metastasis; inhibition or an absence of tumor growth; relief of one or more symptoms associated with the specific cancer; reduced morbidity and mortality; improvement in quality of life; reduction in tumorigenicity, tumorigenic frequency, or tumorigenic capacity, of a tumor; reduction in the number or frequency of cancer stem cells in a tumor; differentiation of tumorigenic cells to a non-tumorigenic state; or some combination of effects. 
     A “variable region” of an antibody refers to the variable region of the antibody light chain or the variable region of the antibody heavy chain, either alone or in combination. The variable regions of the heavy and light chain each consist of four framework regions (FR) connected by three complementarity determining regions (CDRs) also known as hypervariable regions. The CDRs in each chain are held together in close proximity by the FRs and, with the CDRs from the other chain, contribute to the formation of the antigen-binding site of antibodies. There are at least two techniques for determining CDRs: (1) an approach based on cross-species sequence variability (i.e., Kabat et al. Sequences of Proteins of Immunological Interest, (5th ed., 1991, National Institutes of Health, Bethesda Md.)); and (2) an approach based on crystallographic studies of antigen-antibody complexes (Al-lazikani et al (1997)  J. Molec. Biol.  273:927-948)). In addition, combinations of these two approaches are sometimes used in the art to determine CDRs. 
     The terms “polypeptide,” “peptide,” and “protein” are used interchangeably herein to refer to polymers of amino acids of any length. The polymer may be linear or branched, it may comprise modified amino acids, and it may be interrupted by non-amino acids. The terms also encompass an amino acid polymer that has been modified naturally or by intervention; for example, disulfide bond formation, glycosylation, lipidation, acetylation, phosphorylation, or any other manipulation or modification, such as conjugation with a labeling component. Also included within the definition are, for example, polypeptides containing one or more analogs of an amino acid (including, for example, unnatural amino acids, etc.), as well as other modifications known in the art. It is understood that, because the polypeptides of this invention are based upon antibodies, in certain embodiments, the polypeptides can occur as single chains or associated chains. 
     As used in the present disclosure and claims, the singular forms “a,” “an,” and “the” include plural forms unless the context clearly dictates otherwise. 
     It is understood that wherever embodiments are described herein with the language “comprising,” otherwise analogous embodiments described in terms of “consisting of” and/or “consisting essentially of” are also provided. 
     The term “and/or” as used in a phrase such as “A and/or B” herein is intended to include both “A and B,” “A or B,” “A,” and “B.” Likewise, the term “and/or” as used in a phrase such as “A, B, and/or C” is intended to encompass each of the following embodiments: A, B, and C; A, B, or C; A or C; A or B; B or C; A and C; A and B; B and C; A (alone); B (alone); and C (alone). 
     2. Methods of Treatment 
     The present invention provides methods of treating neuroendocrine tumors. Neuroendocrine tumors (NETs) are tumors that arise from cells of the endocrine (hormonal) and nervous systems. Neuroendocrine tumors (NETs) include a group of tumors with a range of morphologic, functional, and behavioral characteristics. These tumors are generally slow growing and behave in an indolent fashion. However, they have the potential to spread, primarily to the liver, and when they do, they can be life threatening and difficult to treat with current modalities. 
     Neuroendocrine tumors are classified by the site of their origin. In certain embodiments, the NET is selected from the group consisting of pancreatic neuroendocrine tumors (pNETs) and carcinoid tumors of the lung, stomach, duodenum, jejunum, ileum, colon and rectum. In further embodiments, the NET is selected from the group consisting neuroendocrine tumors of the ovary, thymus, thyroid medulla, adrenal glands (e.g., pheocromocytoma) and paraganglia (paraganglioma). In certain embodiments, the NET treated by the methods described herein is small cell lung cancer (SCLC). In certain alternative embodiments, the NET is not small cell lung cancer. In certain embodiments, NETs are pancreatic neuroendocrine tumors (PETs) or carcinoid tumors. In certain embodiments, the NET is not small cell lung cancer, a pancreatic cancer, or a thyroid cancer. 
     Neuroendocrine tumors are also classified by grade and differentiation. See, e.g., Phan et al.,  Pancreas,  39(6):784-798 (2012). In certain embodiments, the neuroendocrine tumor is a well differentiated, low grade tumor. In certain embodiments, the neuroendocrine tumor is a moderately differentiated, intermediate grade tumor. In certain embodiments, the neuroendocrine tumor is a poorly differentiated, high grade tumor. In one embodiment, low grade tumors are characterized by &lt;2 mitoses per 10 HPF (high power fields) and no necrosis. In one embodiment, intermediate grade tumors are characterized by 2-10 mitoses per 10 HPF (high power fields) or foci of necrosis. In one embodiment, high grade tumors are characterized by &gt;10 mitoses per 10 HPF (high power fields). 
     Neuroendocrine tumors are also classified as functional and non-functional NETs. NETs are considered functional when a specific clinical syndrome is induced due to excessive production of hormones by the tumor cells. Examples of functional NETs include, but are not limited to, carcinoid tumors, which can result in carcinoid syndrome, and functional pNETs, for example, insulinomas, gastrinomas, vasoactive intestinal peptide (VIP)omas, glucagonomas, and somatostatinomas. Non-functional NETs are not associated with a clinical syndrome due to excessive production of hormones by the tumor cells, but can still produce symptoms related to the presence of the tumor or its metastasis (e.g., abdominal pain or bloating). In certain embodiments, the neuroendocrine tumor is a functional NET. In certain embodiments, the neuroendocrine tumor is a non-functional NET. In certain embodiments, the neuroendocrine tumor is selected from the group consisting of functional carcinoid tumor, insulinoma, gastrinoma, vasoactive intestinal peptide (VIP)oma, glucagonoma, serotoninoma, histaminoma, ACTHoma, pheocromocytoma, and somatostatinoma. In certain embodiments, the neuroendocrine tumor is not SCLC. 
     In certain embodiments, the neuroendocrine tumor is a primary tumor. In certain embodiments, the neuroendocrine tumor is metastatic tumor. In certain embodiments, the neuroendocrine tumor has not spread outside of the wall of the primary organ. In certain embodiments, the neuroendocrine tumor has spread through the wall of the primary organ and to nearby tissues, such as fat, muscle, or lymph nodes. In certain embodiments, the neuroendocrine tumor has spread to tissues or organs away from the primary organ, for example, to the liver, bones, or lungs. 
     In certain embodiments, the neuroendocrine cancer or tumor is refractory to treatment. As a non-limiting example, the cancer or tumor may be chemorefractory (i.e., resistant to one or more forms of chemotherapy). In certain embodiments, the cancer or tumor is resistant to treatment with a somatostatin analog. In certain embodiments, the cancer or tumor is resistant to treatment with a kinase inhibitor. 
     In certain embodiments, the neuroendocrine cancer or tumor has metastasized to the liver. By way of non-limiting example, the neuroendocrine cancer or tumor is a carcinoid or pancreatic neuroendocrine tumor that has metastasized to the liver. 
     In one aspect, the present invention provides the use of a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) in the treatment of neuroendocrine tumor. In certain embodiments, the Wnt antagonist is useful for inhibiting Wnt signaling (e.g., canonical Wnt signaling) in a neuroendocrine tumor cell, inhibiting neuroendocrine tumor growth, inducing neuroendocrine tumor differentiation, reducing neuroendocrine tumor volume, and/or reducing the tumorigenicity of a neuroendocrine tumor. The methods of use can be in vitro, ex vivo, or in vivo methods. In certain embodiments, the Wnt antagonist is the antibody OMP-18R5. In certain embodiments, the Wnt antagonist is the soluble receptor OMP-54F28. 
     The present invention provides for methods of treating neuroendocrine tumor comprising administering a therapeutically effective amount of a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) to a subject (e.g., a subject in need of treatment). In certain embodiments, the neuroendocrine tumor is a pancreatic neuroendocrine tumor. In certain embodiments, the neuroendocrine tumor is a carcinoid. In certain embodiments, the neuroendocrine tumor is neuroendocrine tumor of the lung. By way of non-limiting example, the neuroendocrine tumor in the lung may be SCLC. In certain embodiments, the neuroendocrine tumor is not SCLC. In certain embodiments, the subject is a human. In certain embodiments, the Wnt antagonist is OMP-18R5. In certain embodiments, the Wnt antagonist is OMP-54F28. 
     The present invention further provides methods for inhibiting neuroendocrine tumor growth using the Wnt antagonists (e.g., anti-FZD antibodies and soluble FZD receptors) described herein. In certain embodiments, the method of inhibiting the neuroendocrine tumor growth comprises contacting the tumor cell with a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) in vitro. For example, an immortalized neuroendocrine tumor cell line is cultured in medium to which is added the Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) to inhibit tumor growth. In some embodiments, neuroendocrine tumor cells are isolated from a patient sample such as, for example, a tissue biopsy, pleural effusion, or blood sample and cultured in medium to which is added a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) to inhibit tumor growth. In certain embodiments, the Wnt antagonist is OMP-18R5. In certain embodiments, the Wnt antagonist is OMP-54F28. 
     In some embodiments, the method of inhibiting neuroendocrine tumor growth comprises contacting the neuroendocrine tumor or tumor cells with the Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) in vivo. In certain embodiments, contacting a neuroendocrine tumor or tumor cell with a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) is undertaken in an animal model. For example, a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) may be administered to neuroendocrine tumor xenografts that have been grown in immunocompromised mice (e.g. NOD/SCID mice) to inhibit neuroendocrine tumor growth. In some embodiments, neuroendocrine tumor cancer stem cells are isolated from a patient sample such as, for example, a tissue biopsy, pleural effusion, or blood sample and injected into immunocompromised mice that are then administered a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) to inhibit neuroendocrine tumor cell growth. In some embodiments, the Wnt antagonist (e.g., anti-FZD antibody or soluble FZD receptor) is administered at the same time or shortly after introduction of tumorigenic cells into the animal to prevent neuroendocrine tumor growth. In some embodiments, the Wnt antagonist (e.g., anti-FZD antibody or soluble FZD receptor) is administered as a therapeutic after the tumorigenic cells have grown to a specified size. In certain embodiments, the Wnt antagonist is OMP-18R5. In certain embodiments, the Wnt antagonist is OMP-54F28. 
     In certain embodiments, the method of inhibiting neuroendocrine tumor growth comprises administering to a subject a therapeutically effective amount of a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor). In certain embodiments, the subject is a human. In certain embodiments, the subject has a neuroendocrine tumor or has had a tumor removed. 
     In certain embodiments, the neuroendocrine tumor is a tumor in which Wnt signaling is active. In certain embodiment, the Wnt signaling that is active is canonical Wnt signaling. In certain embodiments, the neuroendocrine tumor is a Wnt-dependent tumor. For example, in some embodiments, the tumor is sensitive to axin over-expression. In certain embodiments, the tumor does not comprise an inactivating mutation (e.g., a truncating mutation) in the adenomatous polyposis coli (APC) tumor suppressor gene or an activating mutation in the beta-catenin gene. In certain embodiments, the tumor expresses one or more genes in a Wnt gene signature, i.e., one or more genes up-regulated or down-regulated by the Wnt signaling pathway. In certain embodiments, the neuroendocrine tumor for which a subject is being treated involves such a tumor. 
     In certain embodiments, the neuroendocrine tumor expresses one or more human frizzled receptors to which the Wnt antagonist FZD-binding antibody described herein binds. In certain embodiments, the neuroendocrine tumor overexpresses the human frizzled receptor(s). In certain embodiments, the Wnt antagonist is OMP-18R5. 
     In certain embodiments, the neuroendocrine tumor expresses one or more human Wnt polypeptides to which the Wnt antagonist soluble FZD receptor described herein binds. In certain embodiments, the neuroendocrine tumor overexpresses the human Wnt polypeptide(s). In certain embodiments, the Wnt antagonist is OMP-54F28. 
     In certain embodiments, the neuroendocrine tumor expresses one or more human Wnt polypeptides to which the Wnt antagonist anti-Wnt antibody described herein binds. In certain embodiments, the neuroendocrine tumor overexpresses the human Wnt polypeptide(s). 
     In certain embodiments, the neuroendocrine tumor is a pancreatic neuroendocrine tumor. In certain embodiments, the neuroendocrine tumor is a carcinoid. In certain embodiments, the neuroendocrine tumor is neuroendocrine tumor of the lung. In certain embodiments, the neuroendocrine tumor is not SCLC. 
     The invention also provides a method of inhibiting Wnt signaling in a neuroendocrine tumor cell comprising contacting the cell with an effective amount of a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor). In certain embodiments, the method is an in vivo method wherein the step of contacting the cell with the Wnt antagonist (e.g., anti-FZD antibody or soluble FZD receptor) comprises administering a therapeutically effective amount of the Wnt antagonist to the subject. In some alternative embodiments, the method is an in vitro or ex vivo method. In certain embodiments, the Wnt signaling that is inhibited is canonical Wnt signaling. In certain embodiments, the Wnt signaling is signaling by Wnt1, Wnt2, Wnt3, Wnt3A, Wnt7a, Wnt7b, and/or Wnt10B. In certain embodiments, the Wnt signaling is signaling by Wnt1, Wnt3A, Wnt7b, and/or Wnt10B. 
     In addition, the invention provides a method of reducing the tumorigenicity of a neuroendocrine tumor in a subject, comprising administering a therapeutically effective amount of a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) to the subject. In certain embodiments, the neuroendocrine tumor comprises cancer stem cells. In certain embodiments, the frequency of cancer stem cells in the neuroendocrine tumor is reduced by administration of the agent. In certain embodiments, the Wnt antagonist is OMP-18R5. In certain embodiments, the Wnt antagonist is OMP-54F28. 
     Thus, the invention also provides a method of reducing the frequency of cancer stem cells in a neuroendocrine tumor, comprising contacting the tumor with an effective amount of a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor). 
     The invention further provides methods of differentiating tumorigenic neuroendocrine tumor cells into non-tumorigenic cells comprising contacting the tumorigenic neuroendocrine tumor cells with a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) by administering the Wnt antagonist to a subject that has a neuroendocrine tumor comprising the tumorigenic cells or that has had such a neuroendocrine tumor removed. 
     The use of the Wnt antagonists (e.g., an anti-FZD antibodies and soluble FZD receptors) described herein to induce the differentiation of neuroendocrine tumor cells is also provided. For example, methods of inducing cells to differentiate comprising contacting the cells with an effective amount of a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) described herein are envisioned. Methods of inducing cells in a neuroendocrine tumor in a subject to differentiate comprising administering a therapeutically effective amount of a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) to the subject are also provided. In certain embodiments, the differentiation of neuroendocrine tumor cells is associated with changes in the radiographic image of the tumor lesion. In certain embodiments, the differentiation of neuroendocrine tumor cells is associated with calcification in the tumor lesion. In certain embodiments, the Wnt antagonist is OMP-18R5. In certain embodiments, the Wnt antagonist is OMP-54F28. 
     Methods of treating a neuroendocrine tumor in a subject, wherein the neuroendocrine tumor is associated with Wnt signaling activation and/or is characterized by an increased level of stem cells and/or progenitor cells are further provided. In some embodiments, the treatment methods comprise administering a therapeutically effective amount of a Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) to the subject. In certain embodiments, the Wnt signaling is canonical Wnt signaling 
     In certain embodiments, in addition to administering the Wnt antagonist (e.g., anti-FZD antibody or soluble FZD receptor) described herein, the method or treatment further comprises administering a second anti-cancer agent (prior to, concurrently with, and/or subsequently to administration of the Wnt antagonist). Pharmaceutical compositions comprising the Wnt antagonist and the second anti-cancer agent are also provided. In certain embodiments, the administration of the combination of the Wnt antagonist and a second anti-cancer agent has a synergistic effect, such as a synergistic effect on the frequency of cancer stem cells. 
     It will be appreciated that the combination of a Wnt antagonist (e.g., anti-FZD antibody or soluble FZD receptor) and a second anti-cancer agent may be administered in any order or concurrently. In selected embodiments, the Wnt antagonist will be administered to patients that have previously undergone treatment with the second anti-cancer agent. In certain other embodiments, the Wnt antagonist and the second anti-cancer agent will be administered substantially simultaneously or concurrently. For example, a subject may be given the Wnt antagonist while undergoing a course of treatment with the second anti-cancer agent (e.g., chemotherapy). In certain embodiments, the Wnt antagonist will be administered within 1 year of the treatment with the second anti-cancer agent. In certain alternative embodiments, the Wnt antagonist will be administered within 10, 8, 6, 4, or 2 months of any treatment with the second anti-cancer agent. In certain other embodiments, the Wnt antagonist will be administered within 4, 3, 2, or 1 week of any treatment with the second anti-cancer agent. In some embodiments, the Wnt antagonist will be administered within 5, 4, 3, 2, or 1 days of any treatment with the second anti-cancer agent. It will further be appreciated that the two agents or treatment may be administered to the subject within a matter of hours or minutes (i.e., substantially simultaneously). 
     Useful classes of anti-cancer agents include, for example, antitubulin agents, auristatins, DNA minor groove binders, DNA replication inhibitors, alkylating agents (e.g., platinum complexes such as cis-platin, mono(platinum), bis(platinum) and tri-nuclear platinum complexes and carboplatin), anthracyclines, antibiotics, antifolates, antimetabolites, chemotherapy sensitizers, duocarmycins, etoposides, fluorinated pyrimidines, ionophores, lexitropsins, nitrosoureas, platinols, performing compounds, purine antimetabolites, puromycins, radiation sensitizers, steroids, taxanes, topoisomerase inhibitors, vinca alkaloids, or the like. In certain embodiments, the second anti-cancer agent is an antimetabolite, an antimitotic, a topoisomerase inhibitor, or an angiogenesis inhibitor. 
     Anticancer agents that may be administered in combination with the Wnt antagonists (e.g., anti-FZD antibodies or soluble FZD receptors) include chemotherapeutic agents. Thus, in some embodiments, the method or treatment involves the combined administration of a Wnt antagonist and a chemotherapeutic agent or cocktail of multiple different chemotherapeutic agents. Treatment with a Wnt antagonist can occur prior to, concurrently with, or subsequent to administration of chemotherapies. Chemotherapies contemplated by the invention include chemical substances or drugs which are known in the art and are commercially available, such as gemcitabine, irinotecan, doxorubicin, 5-fluorouracil, cytosine arabinoside (“Ara-C”), cyclophosphamide, thiotepa, busulfan, cytoxin, TAXOL, methotrexate, cisplatin, melphalan, vinblastine and carboplatin. Combined administration can include co-administration, either in a single pharmaceutical formulation or using separate formulations, or consecutive administration in either order but generally within a time period such that all active agents can exert their biological activities simultaneously. Preparation and dosing schedules for such chemotherapeutic agents can be used according to manufacturers&#39; instructions or as determined empirically by the skilled practitioner. Preparation and dosing schedules for such chemotherapy are also described in Chemotherapy Service Ed., M. C. Perry, Williams &amp; Wilkins, Baltimore, Md. (1992). 
     Chemotherapeutic agents useful in the instant invention also include, but are not limited to, alkylating agents such as thiotepa and cyclosphosphamide (CYTOXAN); alkyl sulfonates such as busulfan, improsulfan, and piposulfan; aziridines such as benzodopa, carboquone, meturedopa, and uredopa; ethylenimines and me thylamelamines including altretamine, triethylenemelamine, trietylenephosphoramide, triethylenethiophosphaoramide and trimethylolomelamime nitrogen mustards such as chlorambucil, chlornaphazine, cholophosphamide, estramustine, ifosfamide, mechlorethamine, mechlorethamine oxide hydrochloride, melphalan, novembichin, phenesterine, prednimustine, trofosfamide, uracil mustard; nitrosureas such as carmustine, chlorozotocin, fotemustine, lomustine, nimustine, ranimustine; antibiotics such as aclacinomysins, actinomycin, authramycin, azaserine, bleomycins, cactinomycin, calicheamicin, carabicin, caminomycin, carzinophilin, chromomycins, dactinomycin, daunorubicin, detorubicin, 6-diazo-5-oxo-L-norleucine, doxorubicin, epirubicin, esorubicin, idarubicin, marcellomycin, mitomycins, mycophenolic acid, nogalamycin, olivomycins, peplomycin, potfiromycin, puromycin, quelamycin, rodorubicin, streptonigrin, streptozocin, tubercidin, ubenimex, zinostatin, zorubicin; anti-metabolites such as methotrexate and 5-fluorouracil (5-FU); folic acid analogues such as denopterin, methotrexate, pteropterin, trimetrexate; purine analogs such as fludarabine, 6-mercaptopurine, thiamiprine, thioguanine; pyrimidine analogs such as ancitabine, azacitidine, 6-azauridine, carmofur, cytarabine, dideoxyuridine, doxifluridine, enocitabine, floxuridine, 5-FU; androgens such as calusterone, dromostanolone propionate, epitiostanol, mepitiostane, testolactone; anti-adrenals such as aminoglutethimide, mitotane, trilostane; folic acid replenisher such as frolinic acid; aceglatone; aldophosphamide glycoside; aminolevulinic acid; amsacrine; bestrabucil; bisantrene; edatraxate; defofamine; demecolcine; diaziquone; elformithine; elliptinium acetate; etoglucid; gallium nitrate; hydroxyurea; lentinan; lonidamine; mitoguazone; mitoxantrone; mopidamol; nitracrine; pentostatin; phenamet; pirarubicin; podophyllinic acid; 2-ethylhydrazide; procarbazine; PSK.; razoxane; sizofuran; spirogermanium; tenuazonic acid; triaziquone; 2,2′,2″-trichlorotriethylamine; urethan; vindesine; dacarbazine; mannomustine; mitobronitol; mitolactol; pipobroman; gacytosine; arabinoside (“Ara-C”); cyclophosphamide; thiotepa; taxoids, e.g. paclitaxel (TAXOL, Bristol-Myers Squibb Oncology, Princeton, N.J.) and doxetaxel (TAXOTERE, Rhone-Poulenc Rorer, Antony, France); chlorambucil; gemcitabine; 6-thioguanine; mercaptopurine; methotrexate; platinum analogs such as cisplatin and carboplatin; vinblastine; platinum; etoposide (VP-16); ifosfamide; mitomycin C; mitoxantrone; vincristine; vinorelbine; navelbine; novantrone; teniposide; daunomycin; aminopterin; xeloda; ibandronate; CPT11; topoisomerase inhibitor RFS 2000; difluoromethylornithine (DMFO); retinoic acid; esperamicins; capecitabine; and pharmaceutically acceptable salts, acids or derivatives of any of the above. Chemotherapeutic agents also include anti-hormonal agents that act to regulate or inhibit hormone action on tumors such as anti-estrogens including for example tamoxifen, raloxifene, aromatase inhibiting 4(5)-imidazoles, 4-hydroxytamoxifen, trioxifene, keoxifene, LY117018, onapristone, and toremifene (Fareston); and antiandrogens such as flutamide, nilutamide, bicalutamide, leuprolide, and goserelin; and pharmaceutically acceptable salts, acids or derivatives of any of the above. 
     In certain embodiments, the chemotherapeutic agent is a kinase inhibitor. In certain embodiments, the kinase inhibitor is a multi-targeted receptor tyrosine kinase inhibitor. Kinase inhibitors include, but are not limited to, sunitinib (marketed as Sutent by Pfizer), pazopanib, crizotinib, dasatinib. In certain embodiments, the second anticancer agent is sunitinib. 
     In certain embodiments, the chemotherapeutic agent is an inhibitor of mammalian target of rapamycin (mTOR). mTOR inhibitors include, but are not limited to, temsirolimus, sirolimus, deforolimus and everolimus. In certain embodiments, the second anticancer agent is everolimus. 
     In certain embodiments, the chemotherapeutic agent is a somatostatin analog. Somatostatin analogs act through interaction with specific, high affinity membrane receptors for somatostatin. Somatostatin analogs include, but are not limited to, octreotide, somatulin, and RC 160 (octastatin). In certain embodiments, the second anticancer agent is octreotide. 
     In certain embodiments, the chemotherapeutic agent is a topoisomerase inhibitor. Topoisomerase inhibitors are chemotherapy agents that interfere with the action of a topoisomerase enzyme (e.g., topoisomerase I or II). Topoisomerase inhibitors include, but are not limited to, doxorubicin HCL, daunorubicin citrate, mitoxantrone HCL, actinomycin D, etoposide, Topotecan HCL, teniposide (VM-26), and irinotecan. In certain embodiments, the second anticancer agent is irinotecan. 
     In certain embodiments, the chemotherapeutic agent is an alkylating agent. In certain embodiments, the chemotherapeutic agent is temozolomide. 
     In certain embodiments, the chemotherapeutic agent is an anti-metabolite. An anti-metabolite is a chemical with a structure that is similar to a metabolite required for normal biochemical reactions, yet different enough to interfere with one or more normal functions of cells, such as cell division. Anti-metabolites include, but are not limited to, gemcitabine, fluorouracil, capecitabine, methotrexate sodium, ralitrexed, pemetrexed, tegafur, cytosine arabinoside, THIOGUANINE (GlaxoSmithKline), 5-azacytidine, 6-mercaptopurine, azathioprine, 6-thioguanine, pentostatin, fludarabine phosphate, and cladribine, as well as pharmaceutically acceptable salts, acids, or derivatives of any of these. In certain embodiments, the second anticancer agent is gemcitabine. In certain embodiments, the tumor to be treated is a pancreatic neuroendocrine tumor and the second anticancer agent is an anti-metabolite (e.g., gemcitabine). 
     In certain embodiments, the chemotherapeutic agent is an antimitotic agent, including, but not limited to, agents that bind tubulin By way of non-limiting example, the agent comprises a taxane. In certain embodiments, the agent comprises paclitaxel or docetaxel, or a pharmaceutically acceptable salt, acid, or derivative of paclitaxel or docetaxel. In certain embodiments, the agent is paclitaxel (TAXOL), docetaxel (TAXOTERE), albumin-bound paclitaxel (e.g., ABRAXANE), DHA-paclitaxel, or PG-paclitaxel. In certain alternative embodiments, the antimitotic agent comprises a vinca alkaloid, such as vincristine, binblastine, vinorelbine, or vindesine, or pharmaceutically acceptable salts, acids, or derivatives thereof. In some embodiments, the antimitotic agent is an inhibitor of Eg5 kinesin or an inhibitor of a mitotic kinase such as Aurora A or Plkl. 
     In certain embodiments, the treatment involves the combined administration of a Wnt antagonist (e.g., anti-FZD antibody or soluble FZD receptor) described herein and radiation therapy. Treatment with the Wnt antagonist can occur prior to, concurrently with, or subsequent to administration of radiation therapy. Any dosing schedule for such radiation therapy can be used as determined by the skilled practitioner. 
     In some embodiments, the second anti-cancer agent comprises an antibody. Thus, treatment can involve the combined administration of a Wnt antagonist (e.g., anti-FZD antibody or soluble FZD receptor) with antibodies against tumor-associated antigens including, but not limited to, antibodies that bind to EGFR, ErbB2, HER2, DLL4, Notch and/or VEGF. Exemplary, anti-DLL4 antibodies, are described, for example, in U.S. Patent Application Publication No. US 2008/0187532, incorporated by reference herein in its entirety. In certain embodiments, the second anti-cancer agent is an antibody that is an angiogenesis inhibitor (e.g., an anti-VEGF antibody). Additional anti-DLL4 antibodies are described in, e.g., International Patent Publication Nos. WO 2008/091222 and WO 2008/0793326, and U.S. Patent Application Publication Nos. US 2008/0014196, US 2008/0175847, US 2008/0181899, and US 2008/0107648, each of which is incorporated by reference herein in its entirety. Exemplary anti-Notch antibodies are described, for example, in U.S. Patent Application Publication No. US 2008/0131434, incorporated by reference herein in its entirety. In certain embodiments, the second anti-cancer agent is an antibody that is an angiogenesis inhibitor (e.g., an anti-VEGF antibody). In certain embodiments, the second anti-cancer agent is an inhibitor of Notch signaling. In certain embodiments, the second anti-cancer agent is AVASTIN (Bevacizumab), Herceptin (Trastuzumab), VECTIBIX (Panitumumab), or Erbitux (Cetuximab). Combined administration can include co-administration, either in a single pharmaceutical formulation or using separate formulations, or consecutive administration in either order but generally within a time period such that all active agents can exert their biological activities simultaneously. 
     Furthermore, treatment can include administration of one or more cytokines (e.g., lymphokines, interleukins, tumor necrosis factors, and/or growth factors) or can be accompanied by surgical removal of cancer cells or any other therapy deemed necessary by a treating physician. 
     For the treatment of the disease, the appropriate dosage of a Wnt antagonist (e.g., anti-FZD antibody or soluble FZD receptor) described herein depends on the type of neuroendocrine tumor to be treated, the severity and course of the neuroendocrine tumor, the responsiveness of the neuroendocrine tumor, whether the Wnt antagonist (e.g., anti-FZD antibody or soluble FZD receptor) is administered for therapeutic or preventative purposes, previous therapy, patient&#39;s clinical history, and so on all at the discretion of the treating physician. The Wnt antagonist (e.g., anti-FZD antibody or soluble FZD receptor) can be administered one time or over a series of treatments lasting from several days to several months, or until a cure is effected or a diminution of the neuroendocrine tumor is achieved (e.g. reduction in tumor size). Optimal dosing schedules can be calculated from measurements of drug accumulation in the body of the patient and will vary depending on the relative potency of an individual Wnt antagonist (e.g., anti-FZD antibody or soluble FZD receptor). The administering physician can easily determine optimum dosages, dosing methodologies and repetition rates. In certain embodiments, dosage is from 0.01 μg to 100 mg per kg of body weight, and can be given once or more daily, weekly, monthly or yearly. In certain embodiments, the Wnt antagonist (e.g., anti-FZD antibody or soluble FZD receptor) is given once every two weeks or once every three weeks. In certain embodiments, the dosage of the Wnt antagonist (e.g., anti-FZD antibody or soluble FZD receptor) is from about 0.1 mg to about 20 mg per kg of body weight. The treating physician can estimate repetition rates for dosing based on measured residence times and concentrations of the drug in bodily fluids or tissues. In certain embodiments, the Wnt antagonist is OMP-18R5. In certain embodiments, the Wnt antagonist is OMP-54F28. 
     In certain embodiments, OMP-18R5 is administered intravenously at a dose of about 0.1 mg/kg to about 20 mg/kg or a dose of about 0.5 mg/kg to about 10 mg/kg. Such doses may, in some embodiments, be given about every week, every two weeks, every three weeks or every four weeks. In certain embodiments, OMP-18R5 is administered intravenously at a dosage of about 0.5 mg/kg to about 10 mg/kg about every two to four weeks. In certain embodiments, OMP-18R5 is administered intravenously at a dosage of about 1.0 mg/kg to about 10 mg/kg approximately about every three weeks. In certain embodiments, OMP-18R5 is administered intravenously at a dosage of (a) at least about 0.5 mg/kg about every one to two weeks or (b) at least about 1.0 mg/kg about every three weeks. In certain embodiments, the antibody is administered at a dosage of about 0.5 mg/kg to about 1.0 mg/kg about every one to two weeks. In some alternative embodiments, the antibody is administered at a dosage of about 1.0 mg/kg to about 5.0 mg/kg about every three weeks. 
     By way of non-limiting example, OMP-54F28 may be administered intravenously at a dose of about 0.1 mg/kg to about 20 mg/kg. This dose may, in some embodiments, be given every week, every two weeks, every three weeks or every four weeks. In certain embodiments, OMP-54F28 is administered intravenously at a dosage of about 0.5 mg/kg to about 10 mg/kg every two to four weeks. In certain embodiments, OMP-54F28 is administered intravenously at a dosage of about 0.5 mg/kg to about 10 mg/kg about every three weeks. 
     3. FZD-Binding Agents 
     Another aspect of the methods of the invention is the use of a FZD-binding agent (e.g., anti-FZD antibody) in the treatment of neuroendocrine tumors. In certain embodiments, the FZD-binding agents (e.g., anti-FZD antibodies) that are useful in the methods of the invention specifically bind one or more human frizzled receptors (FZDs). In certain embodiments, the agents specifically bind two, three, four, five, six, seven, eight, nine, or ten frizzled receptors. The human frizzled receptor or receptors bound by the agent can be selected from the group consisting of FZD1, FZD2, FZD3, FZD4, FZD5, FZD6, FZD7, FZD8, FZD9, and FZD10. In certain embodiments, the one or more human frizzled receptors comprise FZD1, FZD2, FZD5, FZD7, and/or FZD8. In certain embodiments, the one or more human frizzled receptors comprise FZD7. In certain embodiments, the one or more human frizzled receptors comprise FZD5 and/or FZD8. In certain embodiments, the agent specifically binds FZD1, FZD2, FZD5, FZD7, and FZD8. In certain embodiments, the FZD-binding agent specifically binds FZD7. In certain embodiments, the FZD-binding agent specifically binds FZD5. The full-length amino acid (aa) and nucleotide (nt) sequences for FZD1-10 are known in the art and also provided herein as SEQ ID NO:1 (FZD1 aa), SEQ ID NO:2 (FZD2 aa), SEQ ID NO:3 (FZD3 aa), SEQ ID NO:4 (FZD4 aa), SEQ ID NO:5 (FZD5 aa), SEQ ID NO:6 (FZD6 aa), SEQ ID NO:7 (FZD7 aa), SEQ ID NO:8 (FZD8 aa), SEQ ID NO:9 (FZD9 aa), SEQ ID NO:10 (FZD10 aa). 
     In certain embodiments, a FZD-binding agent (e.g., anti-FZD antibody) that is useful in the methods of the invention specifically binds to two or more human frizzled receptors. In certain embodiments, the two or more human frizzled receptors are selected from the group consisting of FZD2, FZD5, FZD7, and FZD8. In certain embodiments, the two or more frizzled receptors comprise FZD 1 and a second frizzled receptor selected from the group consisting of FZD2, FZD5, FZD7, and FZD8. In certain embodiments, the two or more frizzled receptors comprise FZD2 and a second frizzled receptor selected from the group consisting of FZD1, FZD5, FZD7, and FZD8. In certain embodiments, the two or more frizzled receptors comprise FZD5 and a second frizzled receptor selected from the group consisting of FZD1, FZD2, FZD7, and FZD8. In certain embodiments, the two or more frizzled receptors comprise both FZD5 and FZD8. In certain embodiments, the two or more frizzled receptors comprise FZD7 and a second frizzled receptor selected from the group consisting of FZD1, FZD2, FZD5, and FZD8. In certain embodiments, the agent specifically binds to three or more human frizzled receptors. In certain embodiments, the three or more human frizzled receptors comprise three or more frizzled receptors selected from the group consisting of FZD1, FZD2, FZD5, FZD7, and FZD8. In certain embodiments, the agent further specifically binds to one or more additional human frizzled receptors. 
     In certain embodiments, a FZD-binding agent (e.g., anti-FZD antibody) that is useful in the methods of the invention specifically binds to the extracellular domain (ECD) within the one or more human frizzled receptors to which it binds. Sequences of the extracellular domain of each of the human frizzled receptors are known in the art and are also provided as SEQ ID NO:11 (FZD1 ECD), SEQ ID NO:12 (FZD2 ECD), SEQ ID NO:13 (FZD3 ECD), SEQ ID NO:14 (FZD4 ECD), SEQ ID NO:15 (FZD5 ECD), SEQ ID NO:16 (FZD6 ECD), SEQ ID NO:17 (FZD7 ECD), SEQ ID NO:18 (FZD8 ECD), SEQ ID NO:19 (FZD9 ECD), and SEQ ID NO:20 (FZD10 ECD). Particularly useful antibodies are described in U.S. Pat. No. 7,982,013 and U.S. Pat. Appl. Pub. No. 2012/0027778, which are herein incorporated by reference in their entirety. 
     In certain embodiments, a FZD-binding agent (e.g., anti-FZD antibody) that is useful in the methods of the invention specifically binds to the Fri domain (FRI) (also known as the cysteine-rich domain (CRD)) within the human frizzled receptor(s) to which it binds. Sequences of the Fri domain of each of the human frizzled receptors are known in the art and are also provided herein. The Fri domain of FZD1 includes approximately amino acids 87-237 of SEQ ID NO:11. The Fri domain of FZD2 includes approximately amino acids 24-159 of SEQ ID NO:12. The Fri domain of FZD3 includes approximately amino acids 23-143 of SEQ ID NO:13. The Fri domain of FZD4 includes approximately amino acids 40-170 of SEQ ID NO:14. The Fri domain of FZD5 includes approximately amino acids 27-157 of SEQ ID NO:15. The Fri domain of FZD6 includes approximately amino acids 19-146 of SEQ ID NO:16. The Fri domain of FZD7 includes approximately amino acids 33-170 of SEQ ID NO:17. The Fri domain of FZD8 includes approximately amino acids 28-158 of SEQ ID NO:18. The Fri domain of FZD9 includes approximately amino acids 23-159 of SEQ ID NO:19. The Fri domain of FZD10 includes approximately amino acids 21-154 of SEQ ID NO:20. The corresponding, predicted Fri domains for each of the human FZD receptors are provided as SEQ ID NOs:21-30. The minimal, core Fri domain sequences for each of the human FZD receptors (FZD1-10) are provided as SEQ ID NOs:73-82. Those of skill in the art may differ in their understanding of the exact amino acids corresponding to the various Fri domains. Thus in specific embodiments, the N-terminus or C-terminus of the domains outlined above and herein can extend or be shortened by 1, 2, 3, 4, 5, 6, 7, 8, 9, or even 10 amino acids. 
     In certain embodiments, an individual antigen-binding site of a FZD-binding antibody is capable of binding (or binds) the one, two, three, four, or five (or more) human frizzled receptors. In certain embodiments, an individual antigen-binding site of the FZD-binding antibody is capable of specifically binding one, two, three, four, or five human frizzled receptors selected from the group consisting of FZD1, FZD2, FZD5, FZD7, and FZD8. In certain embodiments, an individual binding site of the antibody specifically binds to at least FZD5 and FZD8. 
     In certain embodiments, a FZD-binding agent (e.g., anti-FZD antibody) that is useful in the methods of the invention binds to one or more (for example, two or more, three or more, or four or more) human frizzled receptors with a dissociation constant (K D ) of about 1 μM or less, about 100 nM or less, about 40 nM or less, about 20 nM or less, or about 10 nM or less. For example, in certain embodiments, a FZD-binding agent or antibody that binds to more than one FZD, binds to those FZDs with a K D  of about 100 nM or less, about 20 nM or less, or about 10 nM or less. In certain embodiments, the FZD-binding agent or antibody binds to each of one or more (e.g., 1, 2, 3, 4, or 5) of the following FZDs with a dissociation constant of about 40 nM or less: FZD1, FZD2, FZD5, FZD7, and FZD8. In certain embodiments, the FZD-binding agent or antibody binds to each of one or more of the following FZDs with a dissociation constant of about 10 nM or less: FZD1, FZD2, FZD5, FZD7, and FZD8. In certain embodiments, the FZD-binding agent or antibody binds to each of the following FZDs with a dissociation constant of about 1 nM or less: FZD1, FZD2, FZD5, FZD7, and FZD8. In certain embodiments, the dissociation constant of the agent or antibody to a particular FZD is the dissociation constant determined using an FZD-Fc fusion protein comprising the FZD extracellular domain or Fri domain immobilized on a Biacore chip. 
     In certain embodiments, a FZD-binding agent (e.g., anti-FZD antibody) that is useful in the methods of the invention is an antagonist of at least one human frizzled receptor (i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 FZDs) bound by the agent. In certain embodiments, the agent inhibits at least about 10%, at least about 20%, at least about 30%, at least about 50%, at least about 75%, at least about 90%, or about 100% of one or more activity of the bound human frizzled receptor. 
     In certain embodiments, the FZD-binding agent (e.g., anti-FZD antibody) inhibits binding of a ligand to the at least one human frizzled receptor. In certain embodiments, the ligand is a human Wnt protein. Nineteen human Wnt proteins have been identified: Wnt1, Wnt2, Wnt2B/13, Wnt3, Wnt3A, Wnt4, Wnt5A, Wnt5B, Wnt6, Wnt7A, Wnt7B, Wnt8A, Wnt8B, Wnt9A (previously Wnt14), Wnt9B (previously Wnt15), Wnt10A, Wnt10B, Wnt11, and Wnt16. In certain embodiments, the agent inhibits binding of Wnt3A to FZD8. In certain embodiments, the inhibition of binding of a particular ligand to a particular human frizzled protein provided by the FZD-binding agent is at least about 10%, at least about 25%, at least about 50%, at least about 75%, at least about 90%, or at least about 95%. In certain embodiments, an agent that inhibits binding of a ligand such as a Wnt to a FZD, further inhibits Wnt signaling (e.g., inhibits canonical Wnt signaling). 
     In certain embodiments, the FZD-binding agent (e.g., anti-FZD antibody) inhibits Wnt signaling It is understood that a FZD-binding agent that inhibits Wnt signaling may, in certain embodiments, inhibit signaling by one or more Wnts, but not necessarily by all Wnts. In certain alternative embodiments, signaling by all human Wnts may be inhibited. In certain embodiments, signaling by one or more Wnts selected from the group consisting of Wnt1, Wnt2, Wnt2B/13, Wnt3, Wnt3A, Wnt4, Wnt5A, Wnt5B, Wnt6, Wnt7A, Wnt7B, Wnt8A, Wnt8B, Wnt9A (previously Wnt14), Wnt9B (previously Wnt15), Wnt10A, Wnt10B, Wnt11, and Wnt16 is inhibited. In certain embodiments, the Wnt signaling that is inhibited is signaling by Wnt1, Wnt2, Wnt3, Wnt3A, Wnt7a, Wnt7b, and/or Wnt10B. In certain embodiments, the agent inhibits signaling by (at least) Wnt1, Wnt3A, Wnt7b, and Wnt10B. In particular embodiments, the agent inhibits signaling by (at least) Wnt3A. In certain embodiments, the inhibition of signaling by a Wnt provided by the FZD-binding agent is a reduction in the level of signaling by the Wnt of least about 10%, at least about 25%, at least about 50%, at least about 75%, at least about 90%, or at least about 95%. In certain embodiments, the Wnt signaling that is inhibited is canonical Wnt signaling. 
     In vivo and in vitro assays for determining whether a FZD-binding agent (or candidate FZD-binding agent) inhibits Wnt signaling are known in the art. See, e.g., U.S. Pat. Appl. Pub. No. 2012/0027778, which is incorporated by reference herein in its entirety. 
     In certain embodiments, the FZD-binding agents (e.g., anti-FZD antibodies) useful in the methods of the invention have one or more of the following effects: inhibit proliferation of neuroendocrine tumor cells, reduce the tumorigenicity of a neuroendocrine tumor by reducing the frequency of cancer stem cells in the neuroendocrine tumor, inhibit neuroendocrine tumor growth, increase survival, trigger cell death of neuroendocrine tumor cells, differentiate tumorigenic neuroendocrine tumor cells to a non-tumorigenic state, or prevent metastasis of tumor cells. 
     In certain embodiments, the FZD-binding agents useful in the methods of the invention are capable of inhibiting neuroendocrine tumor growth. In certain embodiments, the FZD-binding agents are capable of inhibiting neuroendocrine tumor growth in vivo (e.g., in a xenograft mouse model and/or in a human having cancer). 
     In certain embodiments, the FZD-binding agents useful in the methods of the invention are capable of reducing the tumorigenicity of a neuroendocrine tumor. In certain embodiments, the agent or antibody is capable of reducing the tumorigenicity of a neuroendocrine tumor comprising cancer stem cells in an animal model, such as a mouse xenograft model. In certain embodiments, the number or frequency of cancer stem cells in a tumor is reduced by at least about two-fold, about three-fold, about five-fold, about ten-fold, about 50-fold, about 100-fold, or about 1000-fold. In certain embodiments, the reduction in the number or frequency of cancer stem cells is determined by limiting dilution assay using an animal model. An example of a limiting dilution assay used to test the efficacy of an anti-FZD antibody is provided in Example 8 of US 2012/0027778, which is incorporated by reference herein in its entirety. Additional examples and guidance regarding the use of limiting dilution assays to determine a reduction in the number or frequency of cancer stem cells in a tumor can be found, e.g., in International Publication Number WO 2008/042236, U.S. Patent Application Publication No. 2008/0064049, and U.S. Patent Application Publication No. 2008/0178305, each of which is incorporated by reference herein in its entirety. 
     In certain embodiments, the FZD-binding agent (e.g., antibody) useful in the methods of the invention is a polypeptide. In certain embodiments, the agent or polypeptide is an antibody. In certain embodiments, the antibody is an IgG1 antibody or an IgG2 antibody. In certain embodiments, the antibody is a monoclonal antibody. In certain embodiments, the antibody is a human antibody or a humanized antibody. In certain embodiments, the antibody is an antibody fragment. 
     In certain embodiments, an anti-FZD antibody for the methods of the invention comprise one, two, three, four, five and/or six of the CDRs of the 18R5, 18R8 and/or 44R24 human antibodies (see Table 1 below) with up to four (i.e., 0, 1, 2, 3, or 4) conservative amino acid substitutions per CDR. In certain embodiments, the heavy chain CDR(s) are contained within a heavy chain variable region and/or the light chain CDR(s) are contained within a light chain variable region. 
     
       
         
           
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 CDRs of 18R8, 18R5, and 44R24 human antibodies 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                   
                 Heavy Chain 
               
            
           
           
               
               
               
               
            
               
                 Ab(s) 
                 CDR1 
                 CDR2 
                 CDR3 
               
               
                   
               
               
                 18R8 
                 GFTFS H YTLS 
                 VISGDGSYTYYADSVKG 
                 NFIKYVFAN 
               
               
                   
                 (SEQ ID NO: 31) 
                 (SEQ ID NO: 32) 
                 (SEQ ID NO: 33) 
               
               
                   
               
               
                 18R5 
                 GFTFS H YTLS 
                 VISGDGSYTYYADSVKG 
                 NFIKYVFAN 
               
               
                   
                 (SEQ ID NO: 31) 
                 (SEQ ID NO: 32) 
                 (SEQ ID NO: 33) 
               
               
                   
               
               
                 44R24 
                 GFTFSSYYIT 
                 TISYSSSNTYYADSVKG 
                 SIVFDY 
               
               
                   
                 (SEQ ID NO: 46) 
                 (SEQ ID NO: 47) 
                 (SEQ ID NO: 48) 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 Light Chain 
               
            
           
           
               
               
               
               
            
               
                 Ab(s) 
                 CDR1 
                 CDR2 
                 CDR3 
               
               
                   
               
               
                 18R8 
                 SGDKLGKKYAS 
                 EKDNRPSG 
                 SSFAGNSLE 
               
               
                   
                 (SEQ ID NO: 41) 
                 (SEQ ID NO: 42) 
                 (SEQ ID NO: 43) 
               
               
                   
               
               
                 18R5 
                 SGDNIGSFYVH 
                 DKSNRPSG 
                 QSYANTLSL 
               
               
                   
                 (SEQ ID NO: 34) 
                 (SEQ ID NO: 35) 
                 (SEQ ID NO: 36) 
               
               
                   
               
               
                 44R24 
                 SGDALGNRYVY 
                 SG 
                 GSWDTRPYPKY 
               
               
                   
                 (SEQ ID NO: 49) 
                 (SEQ ID NO: 50) 
                 (SEQ ID NO: 51) 
               
               
                   
               
               
                 *Site directed change introduced to CDR1 to remove N-linked glycosylation site is underlined. 
               
            
           
         
       
     
     In one embodiment, an anti-FZD antibody that is useful in the methods of the invention comprises a heavy chain variable region comprising: (a) a heavy chain CDR1 comprising GFTFSHYTLS (SEQ ID NO:31), or a variant thereof comprising 1, 2, 3, or 4 amino acid substitutions; (b) a heavy chain CDR2 comprising VISGDGSYTYYADSVKG (SEQ ID NO:32), or a variant thereof comprising 1, 2, 3, or 4 amino acid substitutions; and/or (c) a heavy chain CDR3 comprising NFIKYVFAN (SEQ ID NO:33), or a variant thereof comprising 1, 2, 3, or 4 amino acid substitutions. In certain embodiments, the anti-FZD antibody further comprises a light chain variable region comprising: (a) a light chain CDR1 comprising SGDKLGKKYAS (SEQ ID NO:41), or a variant of thereof comprising 1, 2, 3, or 4 amino acid substitutions; (b) a light chain CDR2 comprising EKDNRPSG (SEQ ID NO:42), or a variant of thereof comprising 1, 2, 3, or 4 amino acid substitutions; and/or (c) a light chain CDR3 comprising SSFAGNSLE (SEQ ID NO:43), or a variant of thereof comprising 1, 2, 3, or 4 amino acid substitutions. In certain embodiments, the amino acid substitutions are conservative substitutions. In a further embodiment, an anti-FZD antibody that is useful in the methods of the invention comprises (a) a heavy chain variable region comprising a heavy chain CDR1 comprising GFTFSHYTLS (SEQ ID NO:31), a heavy chain CDR2 comprising VISGDGSYTYYADSVKG (SEQ ID NO:32), and a heavy chain CDR3 comprising NFIKYVFAN (SEQ ID NO:33); and/or (b) a light chain variable region comprising a light chain CDR1 comprising SGDKLGKKYAS (SEQ ID NO:41), a light chain CDR2 comprising EKDNRPSG (SEQ ID NO:42), and/or a light chain CDR3 comprising SSFAGNSLE (SEQ ID NO:43). 
     In one embodiment, an anti-FZD antibody that is useful in the methods of the invention comprises a heavy chain variable region comprising: (a) a heavy chain CDR1 comprising GFTFSHYTLS (SEQ ID NO:31), or a variant thereof comprising 1, 2, 3, or 4 amino acid substitutions; (b) a heavy chain CDR2 comprising VISGDGSYTYYADSVKG (SEQ ID NO:32), or a variant thereof comprising 1, 2, 3, or 4 amino acid substitutions; and/or (c) a heavy chain CDR3 comprising NFIKYVFAN (SEQ ID NO:33), or a variant thereof comprising 1, 2, 3, or 4 amino acid substitutions. In certain embodiments, the anti-FZD antibody further comprises a light chain variable region comprising: (a) a light chain CDR1 comprising SGDNIGSFYVH (SEQ ID NO:34), or a variant of thereof comprising 1, 2, 3, or 4 amino acid substitutions; (b) a light chain CDR2 comprising DKSNRPSG (SEQ ID NO:35), or a variant of thereof comprising 1, 2, 3, or 4 amino acid substitutions; and/or (c) a light chain CDR3 comprising QSYANTLSL (SEQ ID NO:36), or a variant of thereof comprising 1, 2, 3, or 4 amino acid substitutions. In certain embodiments, the amino acid substitutions are conservative substitutions. In a further embodiment, an anti-FZD antibody that is useful in the methods of the invention comprises (a) a heavy chain variable region comprising a heavy chain CDR1 comprising GFTFSHYTLS (SEQ ID NO:31), a heavy chain CDR2 comprising VISGDGSYTYYADSVKG (SEQ ID NO:32), and a heavy chain CDR3 comprising NFIKYVFAN (SEQ ID NO:33); and/or (b) light chain variable region comprising a light chain CDR1 comprising SGDNIGSFYVH (SEQ ID NO:34), a light chain CDR2 comprising DKSNRPSG (SEQ ID NO:35), and a light chain CDR3 comprising QSYANTLSL (SEQ ID NO:36). 
     In one embodiment, an anti-FZD antibody that is useful in the methods of the invention comprises a heavy chain variable region comprising: (a) a heavy chain CDR1 comprising GFTFSSYYIT (SEQ ID NO:46), or a variant thereof comprising 1, 2, 3, or 4 conservative amino acid substitutions; (b) a heavy chain CDR2 comprising TISYSSSNTYYADSVKG (SEQ ID NO:47), or a variant thereof comprising 1, 2, 3, or 4 conservative amino acid substitutions; and/or (c) a heavy chain CDR3 comprising SIVFDY (SEQ ID NO:48), or a variant thereof comprising 1, 2, 3, or 4 conservative amino acid substitutions. In certain embodiments, the anti-FZD antibody further comprises a light chain variable region comprising: (a) a light chain CDR1 comprising SGDALGNRYVY (SEQ ID NO:49), or a variant thereof comprising 1, 2, 3, or 4 conservative amino acid substitutions; (b) a light chain CDR2 comprising SG (SEQ ID NO:50), or a variant thereof comprising 1, 2, 3, or 4 conservative amino acid substitutions; and (c) a light chain CDR3 comprising GSWDTRPYPKY (SEQ ID NO:51), or a variant thereof comprising 1, 2, 3, or 4 conservative amino acid substitutions. In certain embodiments, the antibody comprises: (a) a heavy chain CDR1 comprising GFTFSSYYIT (SEQ ID NO:46), a heavy chain CDR2 comprising TISYSSSNTYYADSVKG (SEQ ID NO:47), and a heavy chain CDR3 comprising SIVFDY (SEQ ID NO:48); and/or (b) a light chain CDR1 comprising SGDALGNRYVY (SEQ ID NO:49), a light chain CDR2 comprising SG (SEQ ID NO:50), and a light chain CDR3 comprising GSWDTRPYPKY (SEQ ID NO:51). 
     In certain embodiments, an anti-FZD antibody useful for the methods of the invention comprise: (a) a heavy chain variable region having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 97%, or at least about 99% sequence identity to SEQ ID NO:37 or SEQ ID NO:52; and/or (b) a light chain variable region having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 97%, or at least about 99% sequence identity to SEQ ID NO:44, SEQ ID NO:38 or SEQ ID NO:53. In certain embodiments, an anti-FZD antibody useful for the methods of the invention comprise: (a) a heavy chain variable region having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 97%, or at least about 99% sequence identity to SEQ ID NO:37; and (b) a light chain variable region having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 97%, or at least about 99% sequence identity to SEQ ID NO:38. In certain embodiments, the anti-FZD antibody useful for the methods of the invention comprises (a) a heavy chain variable region having the amino acid sequence of SEQ ID NO:37 or SEQ ID NO:52; and/or (b) a light chain variable region having the amino acid sequence of SEQ ID NO:44, SEQ ID NO:38 or SEQ ID NO:53. In certain embodiments, the anti-FZD antibody comprises (a) a heavy chain variable region having the amino acid sequence of SEQ ID NO:37; and/or (b) a light chain variable region having the amino acid sequence of SEQ ID NO:44. In certain embodiments, the anti-FZD antibody comprises (a) a heavy chain variable region having the amino acid sequence of SEQ ID NO:37; and/or (b) a light chain variable region having the amino acid sequence of SEQ ID NO:38. In certain embodiments, the anti-FZD antibody comprises (a) a heavy chain variable region having the amino acid sequence of SEQ ID NO:52; and/or (b) a light chain variable region having the amino acid sequence of SEQ ID NO:53. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 VH and VL of selected human anti-FZD antibodies 
               
            
           
           
               
               
               
            
               
                   
                 Heavy Chain Variable Region 
                 Light Chain Variable Region 
               
               
                 Ab(s) 
                 (VH) amino acid sequence 
                 (VL) amino acid sequence 
               
               
                   
               
               
                 18R8 
                 SEQ ID NO: 37 
                 SEQ ID NO: 44 
               
               
                 18R5 
                 SEQ ID NO: 37 
                 SEQ ID NO: 38 
               
               
                 44R24 
                 SEQ ID NO: 52 
                 SEQ ID NO: 53 
               
               
                   
               
            
           
         
       
     
     In certain embodiments, an anti-FZD antibody useful for the methods of the invention comprises (a) a heavy chain of SEQ ID NO:39 and light chain of SEQ ID NO:45; or (b) a heavy chain of SEQ ID NO:39 and light chain of SEQ ID NO:40. 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 The heavy chain and light chain of 
               
               
                 selected human anti-FZD antibodies 
               
            
           
           
               
               
               
            
               
                   
                 Heavy Chain Variable Region 
                 Light Chain Variable Region 
               
               
                 Ab(s) 
                 (VH) amino acid sequence 
                 (VL) amino acid sequence 
               
               
                   
               
               
                 18R8 
                 SEQ ID NO: 39 
                 SEQ ID NO: 45 
               
               
                 18R5 
                 SEQ ID NO: 39 
                 SEQ ID NO: 40 
               
               
                   
               
            
           
         
       
     
     In certain embodiments, the FZD-binding agent useful in the methods of the invention comprises, consists essentially of, or consists of an anti-FZD antibody selected from the group consisting of 18R8, 18R5, and 44R24 IgG antibodies. 
     In certain embodiments, the FZD-binding agent useful in the methods of the invention comprises the heavy chains and light chains of the 18R8 IgG2 antibody (with or without the leader sequence). In certain embodiments, the FZD-binding agent is the 18R8 IgG2 antibody. DNA encoding the heavy chains and light chains of the 18R8 IgG2 antibody was deposited with the American Type Culture Collection (ATCC), 10801 University Boulevard, Manassas, Va., USA, under the conditions of the Budapest Treaty on Sep. 29, 2008, and assigned ATCC deposit designation number PTA-9540. In certain embodiments, the FZD-binding agent useful in the methods of the invention comprises the heavy chains and light chains of the 18R5 IgG2 antibody (with or without the leader sequence). In certain embodiments, the FZD-binding agent is the 18R5 IgG2 antibody. The 18R5 IgG2 antibody is also referred to herein as OMP-18R5. DNA encoding the heavy chains and light chains of the 18R5 IgG2 antibody was deposited with the ATCC, under the conditions of the Budapest Treaty on Sep. 29, 2008, and assigned ATCC deposit designation number PTA-9541. Additional information regarding the OMP-18R5 antibody can be found, for example, in U.S. Pat. No. 7,982,013, which is incorporated by reference herein in its entirety. In U.S. Pat. No. 7,982,013, the OMP-18R5 antibody is generally referred to as “18R5” or the “18R5 IgG2 antibody.” 
     In certain embodiments, the FZD-binding agent useful in the methods of the invention is an IgG antibody encoded by the plasmid deposited with the ATCC on Aug. 26, 2009, and assigned deposit designation number PTA-10307, PTA-10309, or PTA-10311. 
     In certain embodiments, the FZD-binding agent useful in the methods of the invention is an agent that competes for specific binding to FZD1, FZD2, FZD5, FZD7, and/or FZD8 with an antibody encoded by the plasmid having ATCC deposit designation number PTA-9540, PTA-9541, PTA-10307, or PTA-10309 (e.g., in a competitive binding assay). In certain alternative embodiments, the FZD-binding agent is an agent that competes for specific binding to FZD5 and/or FZD8 with an antibody encoded by the plasmid having ATCC deposit designation number PTA-10311. 
     In certain embodiments, the FZD-binding agent (e.g., antibody) useful in the methods of the invention binds to the same epitope as or binds to an epitope that overlaps with the epitope of the 18R5, 18R8, or 44R24 antibody. 
     In certain embodiments, the FZD-binding agent FZD-binding agent (e.g., antibody) useful in the methods of the invention competes for specific binding to a human frizzled receptor with the 18R5, 18R8, or 44R24 antibody. 
     Further examples of FZD-binding agents useful in the methods of the invention are disclosed in U.S. Pat. Appl. Pub. No. 2012/0027778, which is incorporated by reference herein in its entirety. 
     In certain embodiments, the FZD-binding agent useful in the methods of the invention has a circulating half-life in mice, cynomolgous monkeys, or humans of at least about 10 hours, at least about 24 hours, at least about 3 days, at least about 1 week, or at least about 2 weeks. In certain embodiments, the FZD-binding agent is an IgG (e.g., IgG1 or IgG2) antibody that has a circulating half-life in mice, cynomolgous monkeys, or humans of at least about 10 hours, at least about 24 hours, at least about 3 days, at least about 1 week, or at least about 2 weeks. Methods of increasing the half-life of agents such as polypeptides and antibodies are known in the art. For example, known methods of increasing the circulating half-life of IgG antibodies include the introduction of mutations in the Fc region which increase the pH-dependent binding of the antibody to the neonatal Fc receptor (FcRn) at pH 6.0 (see, e.g., U.S. Pat. Pub. Nos. 2005/0276799, 2007/0148164, and 2007/0122403). Known methods of increasing the circulating half-life of antibody fragments lacking the Fc region include such techniques as PEGylation. 
     In certain embodiments, an anti-FZD antibody useful for the methods of the invention is a bispecific antibody that specifically recognizes a human frizzled receptor. Bispecific antibodies are antibodies that are capable of specifically recognizing and binding at least two different epitopes. In one embodiment, the bispecific anti-FZD antibody specifically recognizes different epitopes within the same human frizzled receptor. In another embodiment, the bispecific anti-FZD antibody specifically recognizes different epitopes within a human frizzled receptor or on different human frizzled receptors. 
     Alternatively, in certain alternative embodiments, an anti-FZD antibody useful for the methods of the invention is not a bispecific antibody. 
     In certain embodiments, an anti-FZD antibody useful for the methods of the invention is monospecific. For example, in certain embodiments, each of the one or more antigen-binding sites that an antibody contains is capable of binding (or binds) the same one or more human FZD receptors (e.g., FZD1, FZD2, FZD5, FZD7, or FZD8, or a homologous epitope on some combination of the FZDs). In certain embodiments, an antigen-binding site of the monospecific anti-FZD antibody is capable of binding (or binds) one, two, three, four, or five (or more) human frizzled receptors. 
     In certain embodiments, the FZD-binding agent useful for the methods of the invention is a polypeptide that is not an antibody. A variety of methods for identifying and producing non-antibody polypeptides that bind with high affinity to a protein target are known in the art. See, e.g., Skerra,  Curr. Opin. Biotechnol.,  18:295-304 (2007), Hosse et al.,  Protein Science,  15:14-27 (2006), Gill et al.,  Curr. Opin. Biotechnol.,  17:653-658 (2006), Nygren,  FEBS J.,  275:2668-76 (2008), and Skerra,  FEBS J.,  275:2677-83 (2008), each of which is incorporated by reference herein in its entirety. 
     In certain embodiments, the FZD-binding agent useful for the methods of the invention comprises a protein scaffold of a type selected from the group consisting of protein A, a lipocalin, a fribronectin domain, an ankyrin consensus repeat domain, and thioredoxin. 
     In certain embodiments, the FZD-binding agent useful for the methods of the invention has been naturally or unnaturally modified. By way of non-limiting example, the polypeptide may be labeled. In certain embodiments, the polypeptide is glycosylated, pegylated, phosphorylated, or acetylated, amidated. In certain embodiments, the modifications increase stability and/or the in vivo half-life of the polypeptide. In certain embodiments, the polypeptides are cyclic. In certain further embodiments, the polypeptides comprise one or more N-methyl amino acids. 
     In certain embodiments, the FZD-binding agent useful for the methods of the invention is (or comprises) a polypeptide comprising an amino acid sequence selected from the group consisting of SEQ ID NOs:54-72, or (b) an amino acid sequence having at least about 80%, at least about 85%, at least about 88%, or at least about 90% amino acid sequence identity to a sequence selected from the group consisting of SEQ ID NOs:54-67 or 69-72. In certain embodiments, the polypeptides comprise, consist essentially of, or consist of a cyclic peptide selected from the group consisting of SEQ ID NOs:54-72. In certain embodiments, the amino acid sequence is SEQ ID NO:64. In certain alternative embodiments, the amino acid sequence is SEQ ID NO:68. 
     In certain embodiments, the FZD-binding polypeptide useful for the methods of the invention is less than about 500 amino acids in length, less than about 200 amino acids in length, less than about 100 amino acids in length, less than about 50 amino acids in length, less than about 20 amino acids amino acids in length, or less than about 15 amino acids in length. In certain embodiments, the FZD-binding polypeptide is at least about 3, at least about 5, or at least about 7 amino acids in length. Accordingly, in certain embodiments the polypeptide is between about 5 and about 20 amino acids in length. In some embodiments, the polypeptide is between about 7 and about 15 amino acids in length. 
     4. Soluble Receptors 
     An additional aspect of the methods of the invention is the use of Wnt antagonist soluble receptors in the treatment of neuroendocrine tumors. In certain embodiments, the soluble receptor useful in the methods of the invention comprises the extracellular domain of a FZD receptor. In some embodiments, the soluble receptor useful in the methods of the invention comprises a Fri domain of a FZD receptor. In certain embodiments, the FZD receptor is a human FZD receptor. In certain embodiments, the human FZD receptor is FZD1, FZD2, FZD3, FZD4, FZD5, FZD6, FZD7, FZD8, FZD9, or FZD10. In certain embodiments, the FZD receptor is FZD8. In certain embodiments, the Wnt antagonist used in the methods described herein comprises a human FZD8 Fri domain and a human Fc region. 
     In some alternative embodiments, the soluble receptor useful in the methods of the invention comprises a portion of a SFRP. In some embodiments, the soluble receptor useful in the methods of the invention comprises a Fri domain of a SFRP. In certain embodiments, the SFRP is a human SFRP. In some embodiments, the human SFRP is SFRP1, SFRP2, SFRP3, SFRP4, or SFRP5. The minimal, core Fri domain sequences for each of the human SFRPs (SFRP1-5) are provided as SEQ ID NOs:83-87. 
     In other alternative embodiments, the soluble receptor useful in the methods of the invention comprises the extracellular domain of a Ror protein. In some embodiments, the soluble receptor useful in the methods of the invention comprises a Fri domain of a Ror protein. In certain embodiments, the Ror is a human Ror. In some embodiments, the human Ror is Ror1 or Ror2. The minimal, core Fri domain sequences of human Ror1 and Ror2 are provided as SEQ ID NO:88 and SEQ ID NO:89. 
     In certain embodiments, the soluble receptors (e.g., FZD8 Fri.Fc) that are useful in the methods of the invention specifically bind one, two, three, four, five, six, seven, eight, nine, ten, or more Wnt proteins. By way of non-limiting example, the Wnt-binding agent may bind Wnt1, Wnt2, Wnt2b, Wnt3, Wnt3a, Wnt7a, Wnt7b, Wnt8a, Wnt8b, Wnt10a, and/or Wnt10b. In certain embodiments, the Wnt-binding agent binds Wnt1, Wnt2, Wnt3, Wnt3a, and Wnt7b. In certain embodiments, the soluble receptor is a Wnt antagonist. In certain embodiments, the soluble receptor inhibits Wnt-signaling. In some embodiments, the soluble receptor inhibits canonical Wnt signaling. 
     Nonlimiting examples of soluble FZD receptors useful in the methods of the invention can be found in U.S. Pat. No. 7,723,477, which is incorporated by reference herein in its entirety. Additional soluble receptors (e.g., soluble FZD receptors) are disclosed in US 2011/0305695, which is incorporated by reference herein in its entirety. 
     In certain embodiments, a soluble receptor useful in the methods of the invention comprises a Fri domain of a human FZD receptor, or a fragment or variant of the Fri domain that binds one or more human Wnt proteins. In certain embodiments, the human FZD receptor is FZD4. In certain alternative embodiments, the human FZD receptor is FZD5. In certain additional alternative embodiments, the human FZD receptor is FZD8. In certain embodiments, the FZD is FZD4 and the soluble receptor comprises SEQ ID NO:76 or comprises approximately amino acids 40 to 170 of SEQ ID NO:90. In certain embodiments, the FZD is FZD5 and the soluble receptor comprises SEQ ID NO:77 or comprises approximately amino acids 27-157 of SEQ ID NO:91. In certain embodiments, the FZD is FZD8 and the soluble receptor comprises SEQ ID NO:80 or comprises approximately amino acids 28-158 of SEQ ID NO:92. 
     In certain embodiments, the soluble receptor useful in the methods of the invention comprises a minimal Fri domain sequence selected from the group consisting of SEQ ID NOs:73-89. In certain embodiments, the soluble receptor useful in the methods of the invention comprises a variant of any one of the aforementioned Fri domain sequences that comprises one or more (e.g., one, two, three, four, five, six, seven, eight, nine, ten, etc.) conservative substitutions and is capable of binding Wnt(s). 
     In certain embodiments, the soluble receptor useful in the methods of the invention, such as a soluble receptor comprising a minimum Fri domain of a human FZD receptor, further comprises a human Fc region (e.g., a human IgG1 Fc region). Soluble receptors comprising the Fri domain of a FZD receptor and human IgG1 Fc are referred to herein as “FZD Fri.Fc” (e.g. FZD8 Fri.Fc). The Fc region can be obtained from any of the classes of immunoglobulin, IgG, IgA, IgM, IgD and IgE. In some embodiments, the Fc region is a wild-type Fc region. In some embodiments, the Fc region is a mutated Fc region. In some embodiments, the Fc region is truncated at the N-terminal end by 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 amino acids, (e.g., in the hinge domain). In some embodiments, an amino acid in the hinge domain is changed to hinder undesirable disulfide bond formation. In some embodiments, a cysteine is replaced with a serine to hinder undesirable disulfide bond formation. In certain embodiments, the Fc region comprises or consists of SEQ ID NO:93, SEQ ID NO:94, or SEQ ID NO:95. 
     In certain embodiments, a soluble receptor useful in the methods of the invention is a fusion protein comprising at least a minimum Fri domain (e.g., a minimum Fri domain of a FZD receptor) and an Fc region. As used herein, a “fusion protein” is a hybrid protein expressed by a nucleic acid molecule comprising nucleotide sequences of at least two genes. In some embodiments, the C-terminus of the first polypeptide is linked to the N-terminus of the immunoglobulin Fc region. In some embodiments, the first polypeptide (e.g., a FZD Fri domain) is directly linked to the Fc region (i.e. without an intervening peptide linker). In some embodiments, the first polypeptide is linked to the Fc region via a peptide linker. 
     As used herein, the term “linker” refers to a linker inserted between a first polypeptide (e.g., a FZD component) and a second polypeptide (e.g., an Fc region). In some embodiments, the linker is a peptide linker. Linkers should not adversely affect the expression, secretion, or bioactivity of the polypeptide. Linkers should not be antigenic and should not elicit an immune response. Suitable linkers are known to those of skill in the art and often include mixtures of glycine and serine residues and often include amino acids that are sterically unhindered. Other amino acids that can be incorporated into useful linkers include threonine and alanine residues. Linkers can range in length, for example from 1-50 amino acids in length, 1-22 amino acids in length, 1-10 amino acids in length, 1-5 amino acids in length, or 1-3 amino acids in length. Linkers may include, but are not limited to, SerGly, GGSG, GSGS, GGGS, S(GGS). where n is 1-7, GRA, poly(Gly), poly(Ala), ESGGGGVT (SEQ ID NO:96), LESGGGGVT (SEQ ID NO:97), GRAQVT (SEQ ID NO:98), WRAQVT (SEQ ID NO:99), and ARGRAQVT (SEQ ID NO:100). As used herein, a linker is an intervening peptide sequence that does not include amino acid residues from either the C-terminus of the first polypeptide (e.g., a FZD Fri domain) or the N-terminus of the second polypeptide (e.g., the Fc region). 
     In certain embodiments, soluble receptors useful for the methods of the invention contain a signal sequence that directs the transport of the proteins. Signal sequences (also referred to as signal peptides or leader sequences) are located at the N-terminus of nascent polypeptides. They target the polypeptide to the endoplasmic reticulum and the proteins are sorted to their destinations, for example, to the inner space of an organelle, to an interior membrane, to the cell&#39;s outer membrane, or to the cell exterior via secretion. Most signal sequences are cleaved from the protein by a signal peptidase after the proteins are transported to the endoplasmic reticulum. The cleavage of the signal sequence from the polypeptide usually occurs at a specific site in the amino acid sequence and is dependent upon amino acid residues within the signal sequence. Although there is usually one specific cleavage site, more than one cleavage site may be recognized and/or used by a signal peptidase resulting in a non-homogenous N-terminus of the polypeptide. For example, the use of different cleavage sites within a signal sequence can result in a polypeptide expressed with different N-terminal amino acids. Accordingly, in some embodiments, the soluble receptors useful for the methods of the invention may comprise a mixture of polypeptides with different N-termini. In some embodiments, the N-termini differ in length by 1, 2, 3, 4, or 5 amino acids. In some embodiments, the soluble receptor polypeptide is substantially homogeneous, i.e., the polypeptides have the same N-terminus. In some embodiments, the signal sequence of the polypeptide comprises amino acid substitutions and/or deletions that allow one cleavage site to be dominant, thereby resulting in a substantially homogeneous polypeptide with one N-terminus. In some embodiments, the signal sequence of the polypeptide comprises or consists of a sequence selected from the group listed in Table 3. In some embodiments, the signal sequence is SEQ ID NO:101. In some embodiments, the signal sequence is SEQ ID NO:104. In some embodiments, the signal sequence is SEQ ID NO:106. 
     
       
         
           
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 Signal sequences. 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 MEWGYLLEVTSLLAALALLQRSSGAAA 
                 SEQ ID NO: 101 
               
               
                   
               
               
                 MEWGYLLEVTSLLAALALLQRSSGALA 
                 SEQ ID NO: 102 
               
               
                   
               
               
                 MEWGYLLEVTSLLAALALLQRSSGVLA 
                 SEQ ID NO: 103 
               
               
                   
               
               
                 MEWGYLLEVTSLLAALLLLQRSPIVHA 
                 SEQ ID NO: 104 
               
               
                   
               
               
                 MEWGYLLEVTSLLAALFLLQRSPIVHA 
                 SEQ ID NO: 105 
               
               
                   
               
               
                 MEWGYLLEVTSLLAALLLLQRSPFVHA 
                 SEQ ID NO: 106 
               
               
                   
               
               
                 MEWGYLLEVTSLLAALLLLQRSPIIYA 
                 SEQ ID NO: 107 
               
               
                   
               
               
                 MEWGYLLEVTSLLAALLLLQRSPIAHA 
                 SEQ ID NO: 108 
               
               
                   
               
            
           
         
       
     
     In certain embodiments, a soluble receptor useful in the methods of the invention comprises a first polypeptide comprising a FZD domain component and an Fc region. In some embodiments, the FZD domain component is from FZD1, FZD2, FZD3, FZD4, FZD5, FZD6, FZD7, FZD8, FZD9, or FZD10. In some embodiments, the Fc region is from an IgG1 immunoglobulin. In some embodiments, the soluble receptor comprises: (a) a first polypeptide consisting essentially of amino acids selected from the group consisting of: X1 to Y1 of SEQ ID NO:11, X2 to Y2 of SEQ ID NO:12, X3 to Y3 of SEQ ID NO:13, X4 to Y4 of SEQ ID NO:14, X5 to Y5 of SEQ ID NO:15, X6 to Y6 of SEQ ID NO:16, X7 to Y7 of SEQ ID NO:17, X8 to Y8 of SEQ ID NO:18, X9 to Y9 of SEQ ID NO:19, and X10 to Y10 of SEQ ID NO:20; and 
     (b) a second polypeptide consisting essentially of amino acids A to B of SEQ ID NO:95; wherein X1=amino acid 69, 70, 71,72, 73, 74, 75, or 76
         Y1=amino acid 236, 237, 238, 239, 240, 241, 242, or 243   X2=amino acid 22, 23, 24, 25, 26, 27 or 28   Y2=amino acid 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171 or 172   X3=amino acid 18, 19, 20, 21, 22, 23, 24, or 25   Y3=amino acid 141, 142, 143, 144, 145, 146, 147, 148, or 149   X4=amino acid 38, 39, 40, 41, or 42   Y4=amino acid 168, 169, 170, 171, 172, 173, 174, 175 or 176   X5=amino acid 25, 26, 27, 28 or 29   Y5=amino acid 155, 156, 157, 158, 159, 160, 161, 162, 163, or 164   X6=amino acid 19, 20, 21, 22, 23, or 24   Y6=amino acid 144, 145, 146, 147, 148, 149, 150, 151 or 152   X7=amino acid 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, or 34   Y7=amino acid 178, 179, 180, 181, 182, 183, 184, 185, or 186   X8=amino acid 25, 26, 27, 28, 29, 30, or 31   Y8=amino acid 156, 157, 158, 159, 160, 161, 162, 163, or 164   X9=amino acid 21, 22, 23, or 24   Y9=amino acid 137, 138, 139, 140, 141, 142, 143, 144, 145, or 146   X10=amino acid 20, 21, 22, 23, 24, or 25   Y10=amino acid 152, 153, 154, 155, 156, 157, 158, 159, or 160   A=amino acid 1, 2, 3, 4, 5, or 6   B=amino acid 231 or 232.       

     In some embodiments, the first polypeptide is directly linked to the second polypeptide. In some embodiments, the first polypeptide is linked to the second polypeptide via a peptide linker. In some embodiments, the first polypeptide is linked to the second polypeptide via the peptide linker GRA. A polypeptide (e.g., a first or second polypeptide) that “consists essentially of” 60  certain amino acids or is “consisting essentially of” certain amino acids may, in some embodiments, include one or more (e.g., one, two, three, four or more) additional amino acids at one or both ends, so long as the additional amino acids do not materially affect the function of the Wnt-binding agent. 
     In certain embodiments, a soluble receptor useful in the methods of the invention comprises: 
     (a) a first polypeptide consisting essentially of amino acids X to Y of SEQ ID NO:18; and (b) a second polypeptide consisting essentially of amino acids A to B of SEQ ID NO:95; wherein the first polypeptide is directly linked to the second polypeptide; and wherein 
     X=amino acid 25, 26, 27, 28, 29, 30, or 31 
     Y=amino acid 156, 157, 158, 159, 160, 161, 162, 163, or 164 
     A=amino acid 1, 2, 3, 4, 5, or 6 
     B=amino acid 231 or 232. 
     In some embodiments, the first polypeptide consists essentially of amino acids 25-158 of SEQ ID NO:18. In other embodiments, the first polypeptide consists of amino acids 25-158 of SEQ ID NO:18. In some embodiments, the first polypeptide consists essentially of amino acids 28-158 of SEQ ID NO:18. In other embodiments, the first polypeptide consists of amino acids 28-158 of SEQ ID NO:18. In some embodiments, the first polypeptide consists of amino acids 31-158 of SEQ ID NO:18. In some embodiments, the second polypeptide consists of amino acids 1-232 of SEQ ID NO:95. In some embodiments, the second polypeptide consists of amino acids 3-232 of SEQ ID NO:95. In some embodiments, the second polypeptide consists of amino acids 6-232 of SEQ ID NO:95. In some embodiments, the first polypeptide is SEQ ID NO:28 and the second polypeptide is SEQ ID NO:95. In some embodiments, the first polypeptide is SEQ ID NO:28 and the second polypeptide is SEQ ID NO:94. In some embodiments, the first polypeptide is SEQ ID NO:28 and the second polypeptide is SEQ ID NO:93. 
     In some embodiments, the soluble receptor useful in the methods of the invention comprises an amino acid sequence selected from the group consisting of SEQ ID NO:109-121. In certain alternative embodiments, the soluble receptor comprises an amino acid sequence selected from the group consisting of SEQ ID NO:109-121, comprising one or more (e.g., one, two, three, four, five, six, seven, eight, nine, ten, etc.) conservative substitutions. In certain embodiments, soluble receptor comprises a sequence having at least about 90%, about 95%, or about 98% sequence identity with an amino acid sequence selected from the group consisting of SEQ ID NO:109-121. In certain embodiments, the variant soluble receptor maintains its ability to bind one or more human Wnts. 
     In certain embodiments, the soluble receptor useful in the methods of the invention comprises the sequence of SEQ ID NO:109. In certain embodiments, the soluble receptor comprises the sequence of SEQ ID NO:115. In some embodiments, the soluble receptor consists of a homodimer formed by polypeptides consisting of SEQ ID NO:115. In certain embodiments, the soluble receptor comprises the sequence of SEQ ID NO:117. In some embodiments, the soluble receptor consists of a homodimer formed by polypeptides consisting of SEQ ID NO:117. 
     In some embodiments, the soluble receptors (e.g., FZD8 Fri.Fc) useful in the methods of the invention inhibit the growth of a neuroendocrine tumor or tumor cells. In some embodiments, the soluble receptors induce neuroendocrine tumor cells to differentiate. In some embodiments, the soluble receptors induce the expression of differentiation markers on a neuroendocrine tumor or tumor cell. In certain embodiments, the soluble receptors reduce the frequency of cancer stem cells in a neuroendocrine tumor. In certain embodiments, the soluble receptors inhibit the growth of a Wnt-dependent neuroendocrine tumor. In some embodiments, a soluble receptor comprising SEQ ID NO:115 inhibits neuroendocrine tumor growth to a greater extent than a soluble receptor comprising SEQ ID NO:109. In some embodiments, a soluble receptor comprising SEQ ID NO:117 inhibits neuroendocrine tumor growth to a greater extent than a soluble receptor comprising SEQ ID NO:109. In some embodiments, a soluble receptor inhibits tumor growth to a greater extent than a soluble receptor comprising a FZD domain component, an Fc domain and a linker component connecting the FZD domain component and the Fc domain. In some embodiments, the linker component is an intervening peptide linker. 
     In certain embodiments, the soluble receptor useful in the methods of the invention (before signal sequence cleavage) comprises SEQ ID NO:115 and a signal sequence selected from the group consisting of SEQ ID NO: 104-108. In some embodiments, the soluble receptor (before signal sequence cleavage) comprises SEQ ID NO:117 and a signal sequence selected from the group consisting of SEQ ID NO: 104-108. In some embodiments, the soluble receptor comprises SEQ ID NO:105 and SEQ ID NO:115. In some embodiments, the soluble receptor comprises SEQ ID NO:105 and SEQ ID NO:117. In some embodiments, the soluble receptor comprises SEQ ID NO:106 and SEQ ID NO:115. In some embodiments, the soluble receptor comprises SEQ ID NO:106 and SEQ ID NO:117. In some embodiments, the soluble receptor comprises SEQ ID NO:133. 
     In some embodiments, the soluble receptor (e.g., FZD8 Fri.Fc) is a substantially purified polypeptide comprising an amino acid sequence selected from the group consisting of SEQ ID NO:109, SEQ ID NO:111, SEQ ID NO:113, SEQ ID NO:115, and SEQ ID NO:117. In certain embodiments, the substantially purified soluble receptor polypeptide comprises at least 80%, at least 90%, at least 95%, at least 97%, at least 98%, or at least 99% polypeptide that has an N-terminal sequence of ASA. In certain embodiments, the substantially purified soluble receptor polypeptide consists of a polypeptide that has an N-terminal sequence of ASA. In some embodiments, the nascent soluble receptor polypeptide comprises a signal sequence selected from the group consisting of SEQ ID NOs: 101-108. In some embodiments, the nascent soluble receptor polypeptide comprises a signal sequence of SEQ ID NO:106. In some embodiments, the nascent soluble receptor polypeptide comprises a signal sequence that results in a substantially homogeneous polypeptide product with one N-terminal sequence. 
     In certain embodiments, the soluble FZD receptor polypeptide is OMP-54F28. OMP-54F28 is a homodimer formed by two polypeptide chains that each consists of SEQ ID NO:117. Additional information regarding OMP-54F28 can be found in U.S. Pat. Appl. Pub. No. 2011/0305695, which is incorporated by reference herein in its entirety. OMP-54F28 is generally referred to as “54F28” in U.S. Pat. Appl. Pub. No. 2011/0305695. 
     In certain embodiments, a soluble receptor (e.g., FZD8 Fri.Fc) useful in the methods of the invention comprises an Fc region of an immunoglobulin. In certain embodiments, at least a portion of the Fc region has been deleted or otherwise altered so as to provide desired biochemical or biological characteristics, such as increased cancer cell localization, increased tumor penetration, reduced serum half-life, or increased serum half-life, reduced or no ADCC activity, reduced or no complement-dependent cytotoxicity (CDC) when compared with a soluble receptor of approximately the same immunogenicity comprising a native or unaltered Fc constant region. Modifications to the Fc region may include additions, deletions, or substitutions of one or more amino acids in one or more domains. Additional soluble receptors (e.g., soluble FZD receptors) comprising a modified Fc region are disclosed in US 2011/0305695, which is incorporated by reference herein in its entirety. 
     In certain embodiments, the soluble receptors (e.g., FZD8 Fri.Fc) useful in the methods of the invention bind to at least one Wnt with a dissociation constant (K D ) of about 1 μM or less, about 100 nM or less, about 40 nM or less, about 20 nM or less, or about 10 nM or less. The soluble receptors can be assayed for specific binding by any method known in the art. Such assays are routine and well known in the art (see, e.g., Ausubel et al, eds, 1994, Current Protocols in Molecular Biology, Vol. 1, John Wiley &amp; Sons, Inc., New York, which is incorporated by reference herein in its entirety). 
     In certain embodiments, the soluble receptor (e.g., FZD8 Fri.Fc) useful in the methods of the invention (e.g., a FZD8 Fri.Fc) is an antagonist of at least one Wnt (i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 Wnts) bound by the soluble receptor. In certain embodiments, the soluble receptor inhibits at least about 10%, at least about 20%, at least about 30%, at least about 50%, at least about 75%, at least about 90%, or about 100% of one or more activity of the bound human Wnt(s). In vivo and in vitro assays for determining whether a soluble receptor inhibits Wnt signaling are known in the art. Suitable methods are disclosed in US 2011/0305695, which is incorporated by reference herein in its entirety. 
     In certain embodiments, a soluble receptor (e.g., FZD8 Fri.Fc) useful in the methods of the invention is derivatized with a water soluble polymer. Suitable water soluble polymers include, but are not limited to, polyethylene glycol (PEG), copolymers of ethylene glycol/propylene glycol, carboxymethylcellulose, dextran, polyvinyl alcohol, polyvinyl pyrrolidone, poly-1,3-dioxolane, poly-1,3,6-trioxane, ethylene/maleic anhydride copolymer, polyaminoacids (either homopolymers or random copolymers), dextran, poly(n-vinyl pyrrolidone)-polyethylene glycol, propropylene glycol homopolymers, prolypropylene oxide/ethylene oxide co-polymers, polyoxyethylated polyols (e.g., glycerol), polyvinyl alcohol, and mixtures thereof. In certain embodiments, the water soluble polymer is polyethylene glycol (PEG). 
     In certain embodiments, the soluble receptor (e.g., FZD8 Fri.Fc) useful in the methods of the invention has a circulating half-life in mice, cynomolgous monkeys, or humans of at least about 5 hours, at least about 10 hours, at least about 24 hours, at least about 3 days, at least about 1 week, or at least about 2 weeks. In certain embodiments, the soluble receptors have a half-life of at least about 50 hours in a rat when administered via the tail vein at a dose ranging from about 2 mg/kg to about 10 mg/kg. In certain embodiments, the soluble receptor is a soluble FZD receptor that comprises a Fri domain of a human FZD receptor (or a fragment or variant of the Fri domain that binds one or more Wnts) and a human Fc region and has a half-life in vivo (e.g., in a mouse or rat) that is longer than a soluble FZD receptor comprising the extracellular domain of the FZD receptor and a human Fc region. 
     5. Anti-Wnt Antibodies 
     A further aspect of the methods of the invention is the use of anti-Wnt antibodies in the treatment of neuroendocrine tumors. In certain embodiments, the anti-Wnt antibodies that are useful in the methods of the invention specifically bind one or more Wnt polypeptides. In certain embodiments, the antibodies specifically bind two, three, four, five, six, seven, eight, nine, ten or more Wnts. The human Wnt(s) bound by the antibody may be selected from the group consisting of Wnt1, Wnt2, Wnt2b, Wnt3, Wnt3a, Wnt4, Wnt5a, Wnt5b, Wnt6, Wnt7a, Wnt7b, Wnt8a, Wnt8b, Wnt9a, Wnt9b, Wnt10a, Wnt10b, Wnt11, and Wnt16. In certain embodiments, the one or more (or two or more, three or more, four or more, five or more, etc.) Wnts bound by the antibody or other antibody comprise Wnt1, Wnt2, Wnt2b, Wnt3, Wnt3a, Wnt7a, Wnt7b, Wnt8a, Wnt8b, Wnt10a, and Wnt10b. In certain embodiments, the one or more (or two or more, three or more, four or more, five or more, etc.) Wnts comprise Wnt1, Wnt2, Wnt2b, Wnt3, Wnt3a, Wnt8a, Wnt8b, Wnt10a, and Wnt10b. 
     In certain embodiments, an individual antigen-binding site of a Wnt-binding antibody useful in the methods of the invention is capable of binding (or binds) the one, two, three, four, or five (or more) human Wnts. In certain embodiments, an individual antigen-binding site of the Wnt-binding antibody is capable of specifically binding one, two, three, four, or five human Wnts selected from the group consisting of Wnt1, Wnt2, Wnt2b, Wnt3, Wnt3a, Wnt7a, Wnt7b, Wnt8a, Wnt8b, Wnt10a, and Wnt10b. 
     In certain embodiments, the Wnt-binding antibody useful in the methods of the invention binds to the C-terminal cysteine rich domain of a human Wnt. In certain embodiments, the antibody binds to a domain (within the one or more Wnt proteins to which the antibody binds) that is selected from the group consisting of SEQ ID NOs:122-132. In some embodiments, the Wnt-binding antibody binds within SEQ ID NO:122. In some embodiments, the Wnt-binding antibody binds within amino acids 288-370 of Wnt1. 
     In certain embodiments, the Wnt-binding antibody useful in the methods of the invention binds to one or more (for example, two or more, three or more, or four or more) Wnts with a dissociation constant (K D ) of about 1 μM or less, about 100 nM or less, about 40 nM or less, about 20 nM or less, or about 10 nM or less. For example, in certain embodiments, a Wnt-binding antibody useful in the methods of the invention that binds to more than one Wnt, binds to those Wnts with a K D  of about 100 nM or less, about 20 nM or less, or about 10 nM or less. In certain embodiments, the Wnt-binding antibody binds to each of one or more (e.g., 1, 2, 3, 4, or 5) of the following Wnts with a dissociation constant of about 40 nM or less: Wnt1, Wnt2, Wnt2b, Wnt3, Wnt3a, Wnt7a, Wnt7b, Wnt8a, Wnt8b, Wnt10a, and Wnt10b. 
     In certain embodiments, the anti-Wnt antibody useful in the methods of the invention is an IgG1 antibody or an IgG2 antibody. In certain embodiments, the antibody is a monoclonal antibody. In certain embodiments, the antibody is a human antibody or a humanized antibody. In certain embodiments, the antibody is an antibody fragment. 
     The antibodies or other antibodies of the present invention can be assayed for specific binding by any method known in the art. Such assays are routine and well known in the art (see, e.g., Ausubel et al, eds, 1994, Current Protocols in Molecular Biology, Vol. 1, John Wiley &amp; Sons, Inc., New York, which is incorporated by reference herein in its entirety). 
     In certain embodiments, the Wnt-binding antibody useful in the methods of the invention is an antagonist of at least one Wnt (i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 Wnts) bound by the antibody. In certain embodiments, the antibody inhibits at least about 10%, at least about 20%, at least about 30%, at least about 50%, at least about 75%, at least about 90%, or about 100% of one or more activity of the bound human Wnt(s). 
     In certain embodiments, the Wnt-binding antibody useful in the methods of the invention inhibits binding of a ligand to the at least one human Wnt. In certain embodiments, the Wnt-binding antibody inhibits binding of a human Wnt protein to one or more of its ligands. Nineteen human Wnt proteins have been identified: Wnt1, Wnt2, Wnt2B/13, Wnt3, Wnt3a, Wnt4, Wnt5a, Wnt5b, Wnt6, Wnt7a, Wnt7b, Wnt8a, Wnt8b, Wnt9a (previously Wnt14), Wnt9b (previously Wnt15), Wnt10a, Wnt10b, Wnt11, and Wnt16. Ten human FZD receptors proteins have been identified (FZD1, FZD2, FZD3, FZD4, FZD5, FZD6, FZD7, FZD8, FZD9, and FZD10). In certain embodiments, the Wnt-binding antibody inhibits binding of FZD4, FZD5, and/or FZD8 to one or more Wnts (e.g., Wnt3a). In certain embodiments, the inhibition of binding of a particular ligand to a Wnt provided by the Wnt-binding antibody is at least about 10%, at least about 25%, at least about 50%, at least about 75%, at least about 90%, or at least about 95%. In certain embodiments, an antibody that inhibits binding of a Wnt to a ligand such as a FZD, further inhibits Wnt signaling (e g., inhibits canonical Wnt signaling) 
     In certain embodiments, the Wnt-binding antibody useful in the methods of the invention inhibits Wnt signaling. It is understood that a Wnt-binding antibody that inhibits Wnt signaling can, in certain embodiments, inhibit signaling by one or more Wnts, but not necessarily by all Wnts. In certain alternative embodiments, signaling by all human Wnts can be inhibited. In certain embodiments, signaling by one or more Wnts selected from the group consisting of Wnt1, Wnt2, Wnt2b/13, Wnt3, Wnt3a, Wnt4, Wnt5a, Wnt5b, Wnt6, Wnt7a, Wnt7b, Wnt8a, Wnt8b, Wnt9a (previously Wnt14), Wnt9b (previously Wnt15), Wnt10a, Wnt10b, Wnt11, and Wnt16 is inhibited. In certain embodiments, the Wnt signaling that is inhibited is signaling by Wnt1, Wnt2, Wnt3, Wnt3a, Wnt7a, Wnt7b, and/or Wnt10b. In certain embodiments, the antibody inhibits signaling by (at least) Wnt1, Wnt3a, Wnt7b, and Wnt10b. In particular embodiments, the antibody inhibits signaling by (at least) Wnt3a. In certain embodiments, the inhibition of signaling by a Wnt provided by the Wnt-binding antibody is a reduction in the level of signaling by the Wnt of least about 10%, at least about 25%, at least about 50%, at least about 75%, at least about 90%, or at least about 95%. In certain embodiments, the Wnt signaling that is inhibited is canonical Wnt signaling. 
     In vivo and in vitro assays for determining whether a Wnt-binding antibody inhibits Wnt signaling are known in the art. For example, cell-based, luciferase reporter assays utilizing a TCF/Luc reporter vector containing multiple copies of the TCF-binding domain upstream of a firefly luciferase reporter gene may be used to measure canonical Wnt signaling levels in vitro (Gazit et al., 1999,  Oncogene,  18; 5959-66). The level of Wnt signaling in the presence of one or more Wnts (e.g., Wnt(s) expressed by transfected cells or provided by Wnt-conditioned media) with the Wnt-binding antibody present is compared to the level of signaling without the Wnt-binding antibody present. In addition to the TCF/Luc reporter assay, the effect of a Wnt-binding antibody (or candidate antibody) on canonical Wnt signaling may be measured in vitro or in vivo by measuring the effect of the antibody on the level of expression of β-catenin regulated genes, such as c-myc (He et al., 1998,  Science,  281:1509-12), cyclin D1 (Tetsu et al., 1999,  Nature,  398:422-6) and/or fibronectin (Gradl et al. 1999,  Mol. Cell Biol.,  19:5576-87). In certain embodiments, the effect of an antibody on Wnt signaling may also be assessed by measuring the effect of the antibody on the phosphorylation state of Dishevelled-1, Dishevelled-2, Dishevelled-3, LRP5, LRP6, and/or β-catenin. 
     In certain embodiments, the Wnt-binding antibodies useful in the methods of the invention have one or more of the following effects. Inhibit proliferation of neuroendocrine tumor cells, reduce the tumorigenicity of a neuroendocrine tumor by reducing the frequency of cancer stem cells in the tumor, inhibit neuroendocrine tumor growth, trigger cell death of neuroendocrine tumor cells, differentiate neuroendocrine tumorigenic cells to a non-tumorigenic state, prevent metastasis of neuroendocrine tumor cells or decrease survival. 
     In certain embodiments, the Wnt-binding antibodies useful in the methods of the invention are capable of inhibiting neuroendocrine tumor growth. In certain embodiments, the Wnt-binding antibodies are capable of inhibiting neuroendocrine tumor growth in vivo (e.g., in a xenograft mouse model, and/or in a human having cancer). 
     In certain embodiments, the Wnt-binding antibodies useful in the methods of the invention are capable of reducing the tumorigenicity of a neuroendocrine tumor. In certain embodiments, the antibody is capable of reducing the tumorigenicity of a neuroendocrine tumor comprising cancer stem cells in an animal model, such as a mouse xenograft model. In certain embodiments, the number or frequency of cancer stem cells in a neuroendocrine tumor is reduced by at least about two-fold, about three-fold, about five-fold, about ten-fold, about 50-fold, about 100-fold, or about 1000-fold. In certain embodiments, the reduction in the number or frequency of cancer stem cells is determined by limiting dilution assay using an animal model. Additional examples and guidance regarding the use of limiting dilution assays to determine a reduction in the number or frequency of cancer stem cells in a tumor can be found, e.g., in International Publication Number WO 2008/042236, U.S. Patent Application Publication No. 2008/0064049, and U.S. Patent Application Publication No. 2008/0178305, each of which is incorporated by reference herein in its entirety. 
     In certain embodiments, the Wnt-binding antibody useful in the methods of the invention has a circulating half-life in mice, cynomolgous monkeys, or humans of at least about 5 hours, at least about 10 hours, at least about 24 hours, at least about 3 days, at least about 1 week, or at least about 2 weeks. In certain embodiments, the Wnt-binding antibody is an IgG (e.g., IgG1 or IgG2) antibody that has a circulating half-life in mice, cynomolgous monkeys, or humans of at least about 5 hours, at least about 10 hours, at least about 24 hours, at least about 3 days, at least about 1 week, or at least about 2 weeks. 
     In certain embodiments, an anti-Wnt antibody useful for the methods of the invention is a bispecific antibody that specifically recognizes a human Wnt. Bispecific antibodies are antibodies that are capable of specifically recognizing and binding at least two different epitopes. In one embodiment, the bispecific anti-Wnt antibody specifically recognizes different epitopes within the same human Wnt. In another embodiment, the bispecific anti-Wnt antibody specifically recognizes different epitopes within different human Wnts or on different Wnts. 
     Alternatively, in certain alternative embodiments, an anti-Wnt antibody useful for the methods of the invention is not a bispecific antibody. 
     In certain embodiments, an anti-Wnt antibody useful for the methods of the invention is monospecific. In certain embodiments, each of the one or more antigen-binding sites that an antibody contains is capable of binding (or binds) the same one or more human Wnts. In certain embodiments, an antigen-binding site of the monospecific antibody is capable of binding (or binds) one, two, three, four, or five (or more) human Wnts. 
     Anti-Wnt antibodies useful for the methods of the invention are disclosed in International Publication Number WO 2011/088127, which is incorporated by reference in its entirety. 
     6. Antibodies and Production Thereof 
     The antibodies (e.g., anti-FZD and anti-Wnt antibodies) useful in the methods of the invention can be produced by any suitable method known in the art. Polyclonal antibodies can be prepared by any known method. Polyclonal antibodies are raised by immunizing an animal (e.g. a rabbit, rat, mouse, donkey, etc.) by multiple subcutaneous or intraperitoneal injections of the relevant antigen (a purified peptide fragment, full-length recombinant protein, fusion protein, etc.) optionally conjugated to keyhole limpet hemocyanin (KLH), serum albumin, etc. diluted in sterile saline and combined with an adjuvant (e.g. Complete or Incomplete Freund&#39;s Adjuvant) to form a stable emulsion. The polyclonal antibody is then recovered from blood, ascites and the like, of an animal so immunized. Collected blood is clotted, and the serum decanted, clarified by centrifugation, and assayed for antibody titer. The polyclonal antibodies can be purified from serum or ascites according to standard methods in the art including affinity chromatography, ion-exchange chromatography, gel electrophoresis, dialysis, etc. 
     Monoclonal antibodies can be prepared using hybridoma methods, such as those described by Kohler and Milstein (1975)  Nature  256:495. Using the hybridoma method, a mouse, hamster, or other appropriate host animal, is immunized as described above to elicit the production by lymphocytes of antibodies that will specifically bind to an immunizing antigen. Lymphocytes can also be immunized in vitro. Following immunization, the lymphocytes are isolated and fused with a suitable myeloma cell line using, for example, polyethylene glycol, to form hybridoma cells that can then be selected away from unfused lymphocytes and myeloma cells. Hybridomas that produce monoclonal antibodies directed specifically against a chosen antigen as determined by immunoprecipitation, immunoblotting, or by an in vitro binding assay (e.g. radioimmunoassay (RIA); enzyme-linked immunosorbent assay (ELISA)) can then be propagated either in vitro culture using standard methods (Goding, Monoclonal Antibodies: Principles and Practice, Academic Press, 1986) or in vivo as ascites tumors in an animal. The monoclonal antibodies can then be purified from the culture medium or ascites fluid as described for polyclonal antibodies above. 
     Alternatively monoclonal antibodies can also be made using recombinant DNA methods as described in U.S. Pat. No. 4,816,567. The polynucleotides encoding a monoclonal antibody are isolated from mature B-cells or hybridoma cell, such as by RT-PCR using oligonucleotide primers that specifically amplify the genes encoding the heavy and light chains of the antibody, and their sequence is determined using conventional procedures. The isolated polynucleotides encoding the heavy and light chains are then cloned into suitable expression vectors, which when transfected into host cells such as  E. coli  cells, simian COS cells, Chinese hamster ovary (CHO) cells, or myeloma cells that do not otherwise produce immunoglobulin protein, monoclonal antibodies are generated by the host cells. Also, recombinant monoclonal antibodies or fragments thereof of the desired species can be isolated from phage display libraries expressing CDRs of the desired species as described (McCafferty et al., 1990,  Nature,  348:552-554; Clackson et al., 1991,  Nature,  352:624-628; and Marks et al., 1991,  J. Mol. Biol.,  222:581-597). 
     The polynucleotide(s) encoding a monoclonal antibody can further be modified in a number of different manners using recombinant DNA technology to generate alternative antibodies. In some embodiments, the constant domains of the light and heavy chains of, for example, a mouse monoclonal antibody can be substituted 1) for those regions of, for example, a human antibody to generate a chimeric antibody or 2) for a non-immunoglobulin polypeptide to generate a fusion antibody. In some embodiments, the constant regions are truncated or removed to generate the desired antibody fragment of a monoclonal antibody. Site-directed or high-density mutagenesis of the variable region can be used to optimize specificity, affinity, etc. of a monoclonal antibody. 
     In some embodiments, the monoclonal antibody useful in the methods of the invention is a humanized antibody. In certain embodiments, such antibodies are used therapeutically to reduce antigenicity and HAMA (human anti-mouse antibody) responses when administered to a human subject. Humanized antibodies can be produced using various techniques known in the art. In certain alternative embodiments, the antibody useful in the methods of the invention is a human antibody. 
     Human antibodies can be directly prepared using various techniques known in the art. 
     Immortalized human B lymphocytes immunized in vitro or isolated from an immunized individual that produce an antibody directed against a target antigen can be generated (See, e.g., Cole et al., Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, p. 77 (1985); Boemer et al., 1991,  J. Immunol.,  147 (1):86-95; and U.S. Pat. No. 5,750,373). Also, the human antibody can be selected from a phage library, where that phage library expresses human antibodies, as described, for example, in Vaughan et al., 1996,  Nat. Biotech.,  14:309-314, Sheets et al., 1998,  Proc. Nat&#39;l. Acad. Sci.,  95:6157-6162, Hoogenboom and Winter, 1991,  J. Mol. Biol.,  227:381, and Marks et al., 1991,  J. Mol. Biol.,  222:581). Techniques for the generation and use of antibody phage libraries are also described in U.S. Pat. Nos. 5,969,108, 6,172,197, 5,885,793, 6,521,404; 6,544,731; 6,555,313; 6,582,915; 6,593,081; 6,300,064; 6,653,068; 6,706,484; and 7,264,963; and Rothe et al., 2007, J. Mol. Bio., doi:10.1016/j.jmb.2007.12.018 (each of which is incorporated by reference in its entirety). Affinity maturation strategies and chain shuffling strategies (Marks et al., 1992,  Bio/Technology  10:779-783, incorporated by reference in its entirety) are known in the art and may be employed to generate high affinity human antibodies. 
     Humanized antibodies can also be made in transgenic mice containing human immunoglobulin loci that are capable upon immunization of producing the full repertoire of human antibodies in the absence of endogenous immunoglobulin production. This approach is described in U.S. Pat. Nos. 5,545,807; 5,545,806; 5,569,825; 5,625,126; 5,633,425; and 5,661,016. 
     In certain embodiments, the antibody useful in the methods of the invention is a bispecific antibody that specifically recognizes a human frizzled receptor or a human Wnt polypeptide. Bispecific antibodies are antibodies that are capable of specifically recognizing and binding at least two different epitopes. The different epitopes can either be within the same molecule (e.g. the same human frizzled receptor or same human Wnt polypeptide) or on different molecules. Bispecific antibodies can be intact antibodies or antibody fragments. 
     Alternatively, in certain alternative embodiments, antibodies useful for the invention are not bispecific antibodies. 
     In certain embodiments, the antibodies useful for the invention are monospecific. For example, in certain embodiments, each of the one or more antigen-binding sites that an antibody contains is capable of binding (or binds) the same human FZD receptor or the same human Wnt polypeptide. In certain embodiments, an antigen-binding site of a monospecific antibody is capable of binding (or binds) one, two, three, four, or five (or more) human frizzled receptors or human Wnt polypeptide. 
     In certain embodiments, an antibody useful for the methods of the invention is an antibody fragment. Antibody fragments can display increased tumor penetration relative to a full antibody. Various techniques are known for the production of antibody fragments. Traditionally, these fragments are derived via proteolytic digestion of intact antibodies (for example Morimoto et al., 1993,  Journal of Biochemical and Biophysical Methods  24:107-117; Brennan et al., 1985,  Science,  229:81). In certain embodiments, antibody fragments are produced recombinantly. Fab, Fv, and scFv antibody fragments can all be expressed in and secreted from  E. coli  or other host cells, thus allowing the production of large amounts of these fragments. Such antibody fragments can also be isolated from the antibody phage libraries discussed above. The antibody fragment can also be linear antibodies as described in U.S. Pat. No. 5,641,870, for example, and can be monospecific or bispecific. Single-chain antibodies useful in the methods of the invention can be prepared as described, for example, in U.S. Pat. No. 4,946,778. In addition, methods can be adapted for the construction of Fab expression libraries (Huse, et al.,  Science  246:1275-1281 (1989)) to allow rapid and effective identification of monoclonal Fab fragments with the desired specificity for a FZD receptor or a Wnt polypeptide. Antibody fragments may be produced by techniques in the art including, but not limited to: (a) a F(ab′)2 fragment produced by pepsin digestion of an antibody molecule; (b) a Fab fragment generated by reducing the disulfide bridges of an F(ab′)2 fragment, (c) a Fab fragment generated by the treatment of the antibody molecule with papain and a reducing agent, and (d) Fv fragments. Other techniques for the production of antibody fragments will be apparent to the skilled practitioner. 
     It can further be desirable, especially in the case of antibody fragments, to modify an antibody in order to increase its serum half-life. This can be achieved, for example, by incorporation of a salvage receptor binding epitope into the antibody fragment by mutation of the appropriate region in the antibody fragment or by incorporating the epitope into a peptide tag that is then fused to the antibody fragment at either end or in the middle (e.g., by DNA or peptide synthesis). 
     In certain embodiments, an antibody useful for the methods of the invention is a heteroconjugate antibody. Heteroconjugate antibodies are composed of two covalently joined antibodies. Such antibodies have, for example, been proposed to target immune cells to unwanted cells (U.S. Pat. No. 4,676,980). It is contemplated that the antibodies can be prepared in vitro using known methods in synthetic protein chemistry, including those involving crosslinking agents. For example, immunotoxins can be constructed using a disulfide exchange reaction or by forming a thioether bond. Examples of suitable reagents for this purpose include iminothiolate and methyl-4-mercaptobutyrimidate. 
     It is known in the art that the constant Fc region mediates several effector functions. For example, binding of the C1 component of complement to antibodies activates the complement system. Activation of complement is important in the opsonization and lysis of cell pathogens. The activation of complement also stimulates the inflammatory response and can also be involved in autoimmune hypersensitivity. Further, antibodies or soluble receptors can bind to cells via the Fc region, with a Fc receptor site on the antibody Fc region binding to a Fc receptor (FcR) on a cell. There are a number of Fc receptors which are specific for different classes of antibody, including IgG (gamma receptors), IgE (epsilon receptors), IgA (alpha receptors) and IgM (mu receptors). Binding of antibody to Fc receptors on cell surfaces triggers a number of important and diverse biological responses including engulfment and destruction of antibody-coated particles, clearance of immune complexes, lysis of antibody-coated target cells by killer cells (called antibody-dependent cell-mediated cytotoxicity, or ADCC), release of inflammatory mediators, placental transfer and control of immunoglobulin production. 
     In certain embodiments, the Wnt antagonist polypeptides (antibodies and Fc comprising soluble receptors) useful for the methods of the invention provide for altered effector functions that, in turn, affect the biological profile of the administered polypeptides. For example, the deletion or inactivation (through point mutations or other means) of a constant region domain may reduce Fc receptor binding of the circulating modified antibody thereby increasing tumor localization. In other cases it may be that constant region modifications moderate complement binding and thus reduce the serum half-life and nonspecific association of a conjugated cytotoxin. Yet other modifications of the constant region may be used to eliminate disulfide linkages or oligosaccharide moieties that allow for enhanced localization due to increased antigen specificity or antibody flexibility. Similarly, modifications to the constant region may easily be made using well known biochemical or molecular engineering techniques well within the purview of the skilled artisan. 
     In certain embodiments, a Wnt antagonist polypeptide comprising an Fc region (antibodies and Fc comprising soluble receptors) useful for the methods of the invention does not have one or more effector functions. For instance, in some embodiments, the polypeptide has no antibody-dependent cellular cytotoxicity (ADCC) activity and/or no complement-dependent cytotoxicity (CDC) activity. In certain embodiments, the polypeptide does not bind to an Fc receptor and/or complement factors. In certain embodiments, the antibody has no effector function. 
     The invention also pertains to the use of immunoconjugates comprising a Wnt antagonist polypeptide (e.g., anti-FZD and anti-Wnt antibody) conjugated to a cytotoxic agent. Cytotoxic agents include chemotherapeutic agents, growth inhibitory agents, toxins (e.g., an enzymatically active toxin of bacterial, fungal, plant, or animal origin, or fragments thereof), radioactive isotopes (i.e., a radioconjugate), etc. Chemotherapeutic agents useful in the generation of such immunoconjugates include, for example, methotrexate, adriamycin, doxorubicin, melphalan, mitomycin C, chlorambucil, daunorubicin or other intercalating agents. Enzymatically active toxins and fragments thereof that can be used include diphtheria A chain, nonbinding active fragments of diphtheria toxin, exotoxin A chain, ricin A chain, abrin A chain, modeccin A chain, alpha-sarcin, Aleurites fordii proteins, dianthin proteins, Phytolaca americana proteins (PAPI, PAPII, and PAP-S), momordica charantia inhibitor, curcin, crotin, sapaonaria officinalis inhibitor, gelonin, mitogellin, restrictocin, phenomycin, enomycin, and the tricothecenes. A variety of radionuclides are available for the production of radioconjugated antibodies including  212 Bi,  131 I,  131 In,  90 Y, and  186 Re. Conjugates of the antibody and cytotoxic agent are made using a variety of bifunctional protein-coupling agents such as N-succinimidyl-3-(2-pyridyidithiol)propionate (SPDP), iminothiolane (IT), bifunctional derivatives of imidoesters (such as dimethyl adipimidate HCL), active esters (such as disuccinimidyl suberate), aldehydes (such as glutareldehyde), bis-azido compounds (such as bis(p-azidobenzoyl)hexanediamine), bis-diazonium derivatives (such as bis-(p-diazoniumbenzoyl)-ethylenediamine), diisocyanates (such as tolyene 2,6-diisocyanate), and bis-active fluorine compounds (such as 1,5-difluoro-2,4-dinitrobenzene). Conjugates of an antibody and one or more small molecule toxins, such as a calicheamicin, maytansinoids, a trichothene, and CC 1065, and the derivatives of these toxins that have toxin activity, can also be used. 
     Conjugate antibodies are composed of two covalently joined antibodies. Such antibodies have, for example, been proposed to target immune cells to unwanted cells (U.S. Pat. No. 4,676,980). It is contemplated that the antibodies can be prepared in vitro using known methods in synthetic protein chemistry, including those involving crosslinking agents. For example, immunotoxins can be constructed using a disulfide exchange reaction or by forming a thioether bond. Examples of suitable reagents for this purpose include iminothiolate and methyl-4-mercaptobutyrimidate. 
     Regardless of how useful quantities are obtained, the Wnt antagonists polypeptides (e.g., antibodies and soluble receptors) useful in the methods of the invention can be used in any one of a number of conjugated (i.e. an immunoconjugate) or unconjugated forms. Alternatively, the polypeptides can be used in a nonconjugated or “naked” form. In certain embodiments, the polypeptides are used in nonconjugated form to harness the subject&#39;s natural defense mechanisms including complement-dependent cytotoxicity (CDC) and antibody dependent cellular toxicity (ADCC) to eliminate the malignant cells. In some embodiments, the polypeptides can be conjugated to radioisotopes, such as  90 Y,  125 I,  131 I,  123 I, 111In,  105 Rh,  153 Sm,  67 Cu,  67 Ga,  166 Ho,  177 Lu,  186 Re and  188 Re using anyone of a number of well-known chelators or direct labeling. In other embodiments, the compositions can comprise Wnt antagonist polypeptides coupled to drugs, prodrugs or biological response modifiers such as methotrexate, adriamycin, and lymphokines such as interferon. Still other embodiments comprise the use of Wnt antagonist polypeptides conjugated to specific biotoxins such as ricin or diptheria toxin. In yet other embodiments, the Wnt antagonist polypeptides can be complexed with other immunologically active ligands (e.g. antibodies or fragments thereof) wherein the resulting molecule binds to both the neoplastic cell and an effector cell such as a T cell. The selection of which conjugated or unconjugated Wnt antagonist polypeptides to use will depend of the type and stage of neuroendocrine tumor, use of adjunct treatment (e.g., chemotherapy or external radiation) and patient condition. It will be appreciated that one skilled in the art could readily make such a selection in view of the teachings herein. 
     The polypeptides and analogs can be further modified to contain additional chemical moieties not normally part of the protein. Those derivatized moieties can improve the solubility, the biological half-life or absorption of the protein. The moieties can also reduce or eliminate any desirable side effects of the proteins and the like. An overview for those moieties can be found in REMINGTON&#39;S PHARMACEUTICAL SCIENCES, 20th ed., Mack Publishing Co., Easton, Pa. (2000). 
     The chemical moieties most suitable for derivatization include water soluble polymers. A water soluble polymer is desirable because the protein to which it is attached does not precipitate in an aqueous environment, such as a physiological environment. In some embodiments, the polymer will be pharmaceutically acceptable for the preparation of a therapeutic product or composition. One skilled in the art will be able to select the desired polymer based on such considerations as whether the polymer/protein conjugate will be used therapeutically, and if so, the desired dosage, circulation time, resistance to proteolysis, and other considerations. The effectiveness of the derivatization can be ascertained by administering the derivative, in the desired form (i.e., by osmotic pump, or by injection or infusion, or, further formulated for oral, pulmonary or other delivery routes), and determining its effectiveness. Suitable water soluble polymers include, but are not limited to, polyethylene glycol (PEG), copolymers of ethylene glycol/propylene glycol, carboxymethylcellulose, dextran, polyvinyl alcohol, polyvinyl pyrrolidone, poly-1,3-dioxolane, poly-1,3,6-trioxane, ethylene/maleic anhydride copolymer, polyaminoacids (either homopolymers or random copolymers), dextran, poly(n-vinyl pyrrolidone)-polyethylene glycol, propropylene glycol homopolymers, prolypropylene oxide/ethylene oxide co-polymers, polyoxyethylated polyols (e.g., glycerol), polyvinyl alcohol, and mixtures thereof. Polyethylene glycol propionaldehyde can have advantages in manufacturing due to its stability in water. 
     The isolated polypeptides (e.g., antibodies and soluble receptors) useful in the methods of the invention can be produced by any suitable method known in the art. Such methods range from direct protein synthetic methods to constructing a DNA sequence encoding isolated polypeptide sequences and expressing those sequences in a suitable transformed host. In some embodiments, a DNA sequence is constructed using recombinant technology by isolating or synthesizing a DNA sequence encoding a wild-type protein of interest. Optionally, the sequence can be mutagenized by site-specific mutagenesis to provide functional analogs thereof. See, e.g. Zoeller et al.,  Proc. Nat&#39;l. Acad. Sci. USA  81:5662-5066 (1984) and U.S. Pat. No. 4,588,585. 
     In some embodiments a DNA sequence encoding a polypeptide of interest would be constructed by chemical synthesis using an oligonucleotide synthesizer. Such oligonucleotides can be designed based on the amino acid sequence of the desired polypeptide and selecting those codons that are favored in the host cell in which the recombinant polypeptide of interest will be produced. Standard methods can be applied to synthesize an isolated polynucleotide sequence encoding an isolated polypeptide of interest. For example, a complete amino acid sequence can be used to construct a back-translated gene. Further, a DNA oligomer containing a nucleotide sequence coding for the particular isolated polypeptide can be synthesized. For example, several small oligonucleotides coding for portions of the desired polypeptide can be synthesized and then ligated. The individual oligonucleotides typically contain 5′ or 3′ overhangs for complementary assembly. 
     Once assembled (by synthesis, site-directed mutagenesis or another method), the polynucleotide sequences encoding a particular isolated polypeptide of interest will be inserted into an expression vector and operatively linked to an expression control sequence appropriate for expression of the protein in a desired host. Proper assembly can be confirmed by nucleotide sequencing, restriction mapping, and expression of a biologically active polypeptide in a suitable host. As is well known in the art, in order to obtain high expression levels of a transfected gene in a host, the gene must be operatively linked to transcriptional and translational expression control sequences that are functional in the chosen expression host. 
     In certain embodiments, recombinant expression vectors are used to amplify and express Wnt antagonist polypeptides (e.g., antibodies or soluble receptors). Recombinant expression vectors are replicable DNA constructs which have synthetic or cDNA-derived DNA fragments encoding a polypeptide of interest operatively linked to suitable transcriptional or translational regulatory elements derived from mammalian, microbial, viral or insect genes. A transcriptional unit generally comprises an assembly of (1) a genetic element or elements having a regulatory role in gene expression, for example, transcriptional promoters or enhancers, (2) a structural or coding sequence which is transcribed into mRNA and translated into protein, and (3) appropriate transcription and translation initiation and termination sequences, as described in detail below. Such regulatory elements can include an operator sequence to control transcription. The ability to replicate in a host, usually conferred by an origin of replication, and a selection gene to facilitate recognition of transformants can additionally be incorporated. DNA regions are operatively linked when they are functionally related to each other. For example, DNA for a signal peptide (secretory leader) is operatively linked to DNA for a polypeptide if it is expressed as a precursor which participates in the secretion of the polypeptide; a promoter is operatively linked to a coding sequence if it controls the transcription of the sequence; or a ribosome binding site is operatively linked to a coding sequence if it is positioned so as to permit translation. Structural elements intended for use in yeast expression systems include a leader sequence enabling extracellular secretion of translated protein by a host cell. Alternatively, where recombinant protein is expressed without a leader or transport sequence, it can include an N-terminal methionine residue. This residue can optionally be subsequently cleaved from the expressed recombinant protein to provide a final product. 
     The choice of expression control sequence and expression vector will depend upon the choice of host. A wide variety of expression host/vector combinations can be employed. Useful expression vectors for eukaryotic hosts include, for example, vectors comprising expression control sequences from SV40, bovine papilloma virus, adenovims and cytomegalovirus. Useful expression vectors for bacterial hosts include known bacterial plasmids, such as plasmids from Esherichia coli, including pCR 1, pBR322, pMB9 and their derivatives, wider host range plasmids, such as M13 and filamentous single-stranded DNA phages. 
     Suitable host cells for expression of a Wnt antagonist polypeptide (e.g., antibody or soluble receptor) include prokaryotes, yeast, insect or higher eukaryotic cells under the control of appropriate promoters. Prokaryotes include gram negative or gram positive organisms, for example  E. coli  or bacilli. Higher eukaryotic cells include established cell lines of mammalian origin as described below. Cell-free translation systems could also be employed. Appropriate cloning and expression vectors for use with bacterial, fungal, yeast, and mammalian cellular hosts are described by Pouwels et al. (Cloning Vectors: A Laboratory Manual, Elsevier, N.Y., 1985), the relevant disclosure of which is hereby incorporated by reference. Additional information regarding methods of protein production, including antibody production, can be found, e.g., in U.S. Patent Publication No. 2008/0187954, U.S. Pat. Nos. 6,413,746 and 6,660,501, and International Patent Publication No. WO 04009823, each of which is hereby incorporated by reference herein in its entirety. 
     Various mammalian or insect cell culture systems are also advantageously employed to express recombinant protein. Expression of recombinant proteins in mammalian cells can be performed because such proteins are generally correctly folded, appropriately modified and completely functional. Examples of suitable mammalian host cell lines include the COS-7 lines of monkey kidney cells, described by Gluzman ( Cell  23:175, 1981), and other cell lines capable of expressing an appropriate vector including, for example, L cells, C127, 3T3, Chinese hamster ovary (CHO), HeLa and BHK cell lines. Mammalian expression vectors can comprise nontranscribed elements such as an origin of replication, a suitable promoter and enhancer linked to the gene to be expressed, and other 5′ or 3′ flanking nontranscribed sequences, and 5′ or 3′ nontranslated sequences, such as necessary ribosome binding sites, a polyadenylation site, splice donor and acceptor sites, and transcriptional termination sequences. Baculovirus systems for production of heterologous proteins in insect cells are reviewed by Luckow and Summers, Bio/Technology 6:47 (1988). 
     The proteins produced by a transformed host can be purified according to any suitable method. Such standard methods include chromatography (e.g., ion exchange, affinity and sizing column chromatography), centrifugation, differential solubility, or by any other standard technique for protein purification. Affinity tags such as hexahistidine, maltose binding domain, influenza coat sequence and glutathione-S-transferase can be attached to the protein to allow easy purification by passage over an appropriate affinity column. Isolated proteins can also be physically characterized using such techniques as proteolysis, nuclear magnetic resonance and x-ray crystallography. 
     For example, supernatants from systems which secrete recombinant protein into culture media can be first concentrated using a commercially available protein concentration filter, for example, an Amicon or Millipore Pellicon ultrafiltration unit. Following the concentration step, the concentrate can be applied to a suitable purification matrix. Alternatively, an anion exchange resin can be employed, for example, a matrix or substrate having pendant diethylaminoethyl (DEAE) groups. The matrices can be acrylamide, agarose, dextran, cellulose or other types commonly employed in protein purification. Alternatively, a cation exchange step can be employed. Suitable cation exchangers include various insoluble matrices comprising sulfopropyl or carboxymethyl groups. Finally, one or more reversed-phase high performance liquid chromatography (RP-HPLC) steps employing hydrophobic RP-HPLC media, e.g., silica gel having pendant methyl or other aliphatic groups, can be employed to further purify a Wnt antagonist polypeptide (e.g., antibody or soluble receptor). Some or all of the foregoing purification steps, in various combinations, can also be employed to provide a homogeneous recombinant protein. 
     Recombinant protein produced in bacterial culture can be isolated, for example, by initial extraction from cell pellets, followed by one or more concentration, salting-out, aqueous ion exchange or size exclusion chromatography steps. High performance liquid chromatography (HPLC) can be employed for final purification steps. Microbial cells employed in expression of a recombinant protein can be disrupted by any convenient method, including freeze-thaw cycling, sonication, mechanical disruption, or use of cell lysing agents. 
     Methods known in the art for purifying a Wnt antagonist polypeptide (e.g., antibody or soluble receptor) also include, for example, those described in U.S. Patent Publication No. 2008/0312425, 2008/0177048, and 2009/0187005, each of which is hereby incorporated by reference herein in its entirety. 
     7. Pharmaceutical Compositions 
     The Wnt antagonist polypeptides (e.g., antibodies and soluble receptors) can be formulated into a pharmaceutical composition by any suitable method known in the art. In certain embodiments, the pharmaceutical compositions comprise a pharmaceutically acceptable vehicle. The pharmaceutical compositions find use in inhibiting neuroendocrine tumor growth and treating neuroendocrine tumor in human patients. 
     In certain embodiments, formulations are prepared for storage and use by combining a purified Wnt antagonist (e.g., an anti-FZD antibody or soluble FZD receptor) with a pharmaceutically acceptable vehicle (e.g. carrier, excipient) (Remington, The Science and Practice of Pharmacy 20th Edition Mack Publishing, 2000). Suitable pharmaceutically acceptable vehicles include, but are not limited to, nontoxic buffers such as phosphate, citrate, and other organic acids; salts such as sodium chloride; antioxidants including ascorbic acid and methionine; preservatives (e.g. octadecyldimethylbenzyl ammonium chloride; hexamethonium chloride; benzalkonium chloride; benzethonium chloride; phenol, butyl or benzyl alcohol; alkyl parabens, such as methyl or propyl paraben; catechol; resorcinol; cyclohexanol; 3-pentanol; and m-cresol); low molecular weight polypeptides (e.g. less than about 10 amino acid residues); proteins such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, histidine, arginine, or lysine; carbohydrates such as monosaccharides, disaccharides, glucose, mannose, or dextrins; chelating agents such as EDTA; sugars such as sucrose, mannitol, trehalose or sorbitol; salt-forming counter-ions such as sodium; metal complexes (e.g. Zn-protein complexes); and non-ionic surfactants such as TWEEN or polyethylene glycol (PEG). 
     In certain embodiments, the pharmaceutical composition is frozen. In certain alternative embodiments, the pharmaceutical composition is lyophilized. 
     The pharmaceutical compositions of the present invention can be administered in any number of ways for either local or systemic treatment. Administration can be topical (such as to mucous membranes including vaginal and rectal delivery) such as transdermal patches, ointments, lotions, creams, gels, drops, suppositories, sprays, liquids and powders; pulmonary (e.g., by inhalation or insufflation of powders or aerosols, including by nebulizer; intratracheal, intranasal, epidermal and transdermal); oral; or parenteral including intravenous, intraarterial, subcutaneous, intraperitoneal or intramuscular injection or infusion; or intracranial (e.g., intrathecal or intraventricular) administration. 
     The therapeutic formulation can be in unit dosage form. Such formulations include tablets, pills, capsules, powders, granules, solutions or suspensions in water or non-aqueous media, or suppositories for oral, parenteral, or rectal administration or for administration by inhalation. In solid compositions such as tablets the principal active ingredient is mixed with a pharmaceutical carrier. Conventional tableting ingredients include corn starch, lactose, sucrose, sorbitol, talc, stearic acid, magnesium stearate, dicalcium phosphate or gums, and other diluents (e.g. water) to form a solid preformulation composition containing a homogeneous mixture of a compound of the present invention, or a non-toxic pharmaceutically acceptable salt thereof. The solid preformulation composition is then subdivided into unit dosage forms of the type described above. The tablets, pills, etc. of the novel composition can be coated or otherwise compounded to provide a dosage form affording the advantage of prolonged action. For example, the tablet or pill can comprise an inner composition covered by an outer component. Furthermore, the two components can be separated by an enteric layer that serves to resist disintegration and permits the inner component to pass intact through the stomach or to be delayed in release. A variety of materials can be used for such enteric layers or coatings, such materials including a number of polymeric acids and mixtures of polymeric acids with such materials as shellac, cetyl alcohol and cellulose acetate. 
     The Wnt antagonists (e.g., anti-FZD antibodies or soluble FZD receptors) can also be entrapped in microcapsules. Such microcapsules are prepared, for example, by coacervation techniques or by interfacial polymerization, for example, hydroxymethylcellulose or gelatin-microcapsules and poly-(methylmethacylate) microcapsules, respectively, in colloidal drug delivery systems (for example, liposomes, albumin microspheres, microemulsions, nano-particles and nanocapsules) or in macroemulsions as described in Remington, The Science and Practice of Pharmacy 20th Ed. Mack Publishing (2000). 
     In certain embodiments, pharmaceutical formulations include the Wnt antagonists (e.g., anti-FZD antibodies or soluble FZD receptors) complexed with liposomes (Epstein, et al., 1985,  Proc. Natl. Acad. Sci. USA  82:3688; Hwang, et al., 1980,  Proc. Natl. Acad. Sci. USA  77:4030; and U.S. Pat. Nos. 4,485,045 and 4,544,545). Liposomes with enhanced circulation time are disclosed in U.S. Pat. No. 5,013,556. Some liposomes can be generated by the reverse phase evaporation with a lipid composition comprising phosphatidylcholine, cholesterol, and PEG-derivatized phosphatidylethanolamine (PEG-PE). Liposomes are extruded through filters of defined pore size to yield liposomes with the desired diameter. 
     In addition sustained-release preparations can be prepared. Suitable examples of sustained-release preparations include semipermeable matrices of solid hydrophobic polymers containing the antibody, which matrices are in the form of shaped articles (e.g. films, or microcapsules). Examples of sustained-release matrices include polyesters, hydrogels such as poly(2-hydroxyethyl-methacrylate) or poly(v nylalcohol), polylactides (U.S. Pat. No. 3,773,919), copolymers of L-glutamic acid and 7 ethyl-L-glutamate, non-degradable ethylene-vinyl acetate, degradable lactic acid-glycolic acid copolymers such as the LUPRON DEPOT™ (injectable microspheres composed of lactic acid-glycolic acid copolymer and leuprolide acetate), sucrose acetate isobutyrate, and poly-D-(−)-3-hydroxybutyric acid. 
     EXAMPLES 
     It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application. 
     Example 1 
     Neuroendocrine Tumor Response to OMP-18R5 in a Phase 1a Clinical Study 
     In the context of a Phase I clinical trial for the OMP-18R5 human anti-FZD antibody in patients with advanced solid tumors, three patients with late stage neuroendocrine tumors that had previously undergone multiple other therapies were treated with low, periodic doses of OMP-18R5 as a single agent. The prolonged stable disease of all three of these neuroendocrine patients suggests that even as a single agent at low dosages OMP-18R5 may have a surprising level of efficacy against neuroendocrine tumors, including both neuroendocrine tumors having carcinoid histology and pancreatic neuroendocrine tumors. 
     At the time of her enrollment in the OMP-18R5 trial, Patient 3 was a 59 years old female. She was diagnosed with neuroendocrine tumor (carcinoid) in 2004. She underwent a small bowel resection and was treated with radiofrequency ablation of liver lesions. Prior to enrollment in the OMP-18R5 trial, she received prior systemic treatment with a combination of trametinib (MEK1/2 MAP kinase inhibitor) and GSK2141795 Akt inhibitor but her disease progressed after 1 month of treatment. In the OMP-18R5 trial Patient 3 received a weekly dose of 0.5 mg/kg OMP-18R5 for 112 days. Her disease remained stable during OMP-18R5 treatment, but she was removed from the trial after suffering a bone fracture on day 112. Especially in light of her rapid disease progression while on a previous therapy, this patient&#39;s extended period of disease control while being treated with OMP-18R5 suggests that the antibody may have a surprising level of clinical efficacy even as a single agent at a low dose. 
     At the time of her enrollment in the OMP-18R5 trial, Patient 10 was a 69 year old female with pancreatic neuroendocrine tumor. She was diagnosed in 2001 and treated with surgery comprising 80% distal pancreatectomy, splenectomy, and wedge resection of posterior wall of stomach. Prior to enrollment in the OMP-18R5 trial, she received systemic treatments with (1) regorafenib (partial response: 3 years); (2) anti-LOXL2 antibody (stable disease: 5.5 months); and (3) anti-CSFR1 antibody (progressive disease after 6 weeks on study). As of Jan. 25, 2013, Patient 10 in the OMP-18R5 trial had received 0.5 mg/kg OMP-18R5 every other week for 279 days. After 112 days of OMP-18R5 treatment, a 21% reduction in Patient 10&#39;s target tumor liver metastasis was determined by the investigator. Tumor reduction was confirmed by an independent radiographic assessment (shown in Table 4). See  FIG. 1A . The control non-target disease lesion showed no change during the same treatment period. Radiographic examination further revealed signs of calcification in the tumor lesion of Patient 10 following 112 days of OMP-18R5 treatment ( FIGS. 1B  and C). The observed calcification of the tumor lesion may indicate that OMP-18R5 induced differentiation of the tumor cells and/or tumor necrosis. Subsequent computed tomography (CT) scans on days 168, 224 and 280 indicated that the patient still did not have progressive disease. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Patient 10: Independent Radiographic Assessment RECIST 1.1 
               
            
           
           
               
               
               
               
            
               
                   
                 Mar. 27, 
                   
                   
               
               
                   
                 2012 
                 Jun. 11, 
                 Aug. 6, 
               
               
                 Lesion (mm) 
                 (BASELINE) 
                 2012 
                 2012 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 1. 
                 Liver: Rt Lobe 
                 13.6 ×  22.9   
                 17.3 ×  23.9   
                 13.3 ×  20.5   
               
               
                   
                 (Ant-Lat) 
               
               
                   
                 (TARGET) 
               
               
                 2. 
                 Liver: IVC 
                 16.2 ×  16.2   
                 15.9 ×  15.9   
                 10.8 ×  13.1   
               
               
                   
                 (TARGET) 
               
               
                 3. 
                 Liver: Rt Dome 
                  7.9 ×  11.6   
                  7.1 ×  11.4   
                 4.9 ×  8.5   
               
               
                   
                 (TARGET) 
               
               
                 4. 
                 Porto-caval Node 
                 16.6 ×  23.9   
                 14.1 ×  15.5   
                  9.1 ×  14.2   
               
               
                   
                 (TARGET)* 
               
               
                 5. 
                 Porto-caval Node 
                   11.1  × 14.5 
                   10.5  × 12.6 
                   9.5  × 14.8 
               
               
                   
                 (NON-TARGET) 
               
            
           
           
               
               
               
               
            
               
                 TOTAL: Target (mm, % Δ) 
                 67.3 
                 65.3 (−3%) 
                 51.2 (−24%) 
               
               
                 TOTAL: Non-Target 
                 Non-PD 
                 Non-PD 
                 Normal** 
               
               
                   
               
               
                 *Per RECIST 1.1: LN ≧ 15 mm in shortest diameter are measurable 
               
               
                 **Per RECIST 1.1: LN &lt; 10 mm in shortest diameter considered ‘normal’ 
               
               
                 Non-PD: non-progressive disease 
               
            
           
         
       
     
     At the time of her enrollment in the OMP-18R5 trial, Patient 12 was a 77 year old female with a neuroendocrine tumor (carcinoid). She was diagnosed in 2006. Prior to enrollment in the OMP-18R5 trial, she received systemic treatments with (1) sandostatin (stable disease: 20 months); (2) inhibitor of heat shock protein 90 (stable disease: 23 months); and (3) a combination of sandostatin and anti-angiopoietin-2 antibody (stable disease: 4 months). As of Jan. 25, 2013, Patient 12 in the OMP-18R5 trial had received lmg/kg OMP-18R5 every third week for 210 days. This patient was assessed to have stable disease on days 56, 112 and 168. The extended period of time during which this patient has remained on the clinical trial without disease progression further supports the clinical efficacy of OMP-18R5 against neuroendocrine tumors. 
       FIG. 2  shows the number of days that each of the patients (n=18) enrolled in the OMP-18R5 Phase 1a study as of Jan. 25, 2013, stayed on the OMP-18R5 Phase 1a study. The patients with neuroendocrine tumors that had been treated with OMP-18R5 remained on study for surprisingly long periods of times relative to the other Phase 1a patients having other tumor types (including colorectal cancer, breast cancer, melanoma and pancreatic cancer). 
     Also, as of Jan. 25, 2013, the three patients with neuroendocrine tumors had had stable disease ˜2- to 7-fold longer on OMP-18R5 treatment than when they were on the prior therapies on which they previously progressed. Using Growth Modulation Index as a tool to gauge the observed activity (time on current therapy divided by time on prior therapy before progressive disease; GMI≧1.33 considered excellent;  Von Hoff; Clinical Cancer Research  4:1079-1086, 1998), all three neuroendocrine (NET) patients significantly surpassed this mark (Patient 12: 1.8; Patient 10: 6.3; Patient 3, off study: 3.8). A comparison of the time each of the three neuroendocrine tumor patients remained on the OMP-18R5 study (as of Jan. 25, 2013) versus her time on prior therapies is shown in  FIG. 3 . 
     Example 2 
     In vivo Prevention of Neuroendocrine Tumor Growth Using a Wnt Antagonist 
     This example describes a use of a Wnt antagonist (e.g., OMP-18R5 or OMP-54F28) to prevent neuroendocrine tumor growth in a xenograft model. In certain embodiments, neuroendocrine tumor cells from a patient sample (solid tumor biopsy or pleural effusion) that have been passaged as a xenograft in mice are prepared for repassaging into experimental animals. Neuroendocrine tumor tissue is removed under sterile conditions, cut up into small pieces, minced completely using sterile blades, and single cell suspensions obtained by enzymatic digestion and mechanical disruption. Specifically, pleural effusion cells or the resulting tumor pieces are mixed with ultra-pure collagenase III in culture medium (200-250 units of collagenase per mL) and incubated at 37° C. for 3-4 hours with pipetting up and down through a 10 mL pipette every 15-20 minutes. Digested cells are filtered through a 45 μM nylon mesh, washed with RPMI/20% FBS, and washed twice with HBSS. Dissociated neuroendocrine tumor cells are then injected subcutaneously into the mammary fat pads of NOD/SCID mice to elicit tumor growth. 
     In certain embodiments, dissociated neuroendocrine tumor cells are first sorted into tumorigenic and non-tumorigenic cells based on cell surface markers before injection into experimental animals. Specifically, neuroendocrine tumor cells dissociated as described above are washed twice with Hepes buffered saline solution (HBSS) containing 2% heat-inactivated calf serum (HICS) and resuspended at 10 6  cells per 100 μl. Antibodies are added and the cells incubated for 20 minutes on ice followed by two washes with HBSS/2% HICS. Antibodies include anti-ESA (Biomeda, Foster City, Calif.), anti-CD44, anti-CD24, and Lineage markers anti-CD2, -CD3, -CD10, -CD16, -CD18, -CD31, -CD64, and -CD140b (collectively referred to as Lin; PharMingen, San Jose, Calif.). Antibodies are directly conjugated to fluorochromes to positively or negatively select cells expressing these markers. Mouse cells are eliminated by selecting against H2Kd+ cells, and dead cells are eliminated by using the viability dye 7AAD. Flow cytometry is performed on a FACSVantage (Becton Dickinson, Franklin Lakes, N.J.). Side scatter and forward scatter profiles are used to eliminate cell clumps. Isolated ESA+, CD44+, CD24-/low, Lin-tumorigenic cells are then injected subcutaneously into NOD/SCID mice to elicit tumor growth. 
     By way of example, Wnt antagonists (e.g., OMP-18R5 or OMP-54F28) are analyzed for their ability to reduce the growth of neuroendocrine tumor cells. Dissociated neuroendocrine tumor cells (10,000 per animal) are injected subcutaneously into the flank region of 6-8 week old NOD/SCID mice. Two days after tumor cell injection, animals are injected intraperitoneal (i.p.) with 10 mg/kg anti-FZD antibody or soluble FZD receptor two times per week. Tumor growth is monitored weekly until growth is detected, after which point tumor growth is measured twice weekly for a total of 8 weeks. FZD-binding antibodies which significantly reduce tumor growth as compared to PBS injected controls are thus identified. 
     Example 3 
     In vivo Treatment of Neuroendocrine Tumors Using a Wnt Antagonist 
     This example describes the use of a Wnt antagonists (e.g., OMP-18R5 or OMP-54F28) to treat neuroendocrine cancer in a xenograft model. In certain embodiments, neuroendocrine tumor cells from a patient sample (solid tumor biopsy or pleural effusion) that have been passaged as a xenograft in mice are prepared for repassaging into experimental animals. Neuroendocrine tumor tissue is removed, cut up into small pieces, minced completely using sterile blades, and single cell suspensions obtained by enzymatic digestion and mechanical disruption. Dissociated neuroendocrine tumor cells are then injected subcutaneously either into the mammary fat pads, for breast tumors, or into the flank, for non-breast tumors, of NOD/SCID mice to elicit tumor growth. Alternatively, ESA+, CD44+, CD24-/low, Lin-tumorigenic tumor cells are isolated as described above and injected. 
     Following tumor cell injection, animals are monitored for tumor growth. Once neuroendocrine tumors reach an average size of approximately 150 to 200 mm, Wnt antagonist (e.g., OMP-18R5 or OMP-54F28) treatment begins. Each animal receives 100 μg Wnt antagonist (e.g., OMP-18R5 or OMP-54F28) or control agents i.p. two to five times per week for a total of 6 weeks. Tumor size is assessed twice a week during these 6 weeks. The ability of Wnt antagonists (e.g., OMP-18R5 or OMP-54F28) to prevent further neuroendocrine tumor growth or to reduce neuroendocrine tumor size compared to control agents is thus determined. 
     At the end point of antibody treatment, tumors are harvested for further analysis. In some embodiments a portion of the neuroendocrine tumor is analyzed by immunofluorescence to assess Wnt antagonist (e.g., OMP-18R5 or OMP-54F28) penetration into the tumor and tumor response. A portion of each harvested neuroendocrine tumor from Wnt antagonist (e.g., OMP-18R5 or OMP-54F28) treated and control mice is fresh-frozen in liquid nitrogen, embedded in OCT., and cut on a cryostat as 10 μm sections onto glass slides. In some embodiments, a portion of each neuroendocrine tumor is formalin-fixed, paraffin-embedded, and cut on a microtome as 10 μm section onto glass slides. Sections are post-fixed and incubated with chromophore labeled antibodies that specifically recognize the injected Wnt antagonist (e.g., OMP-18R5 or OMP-54F28) to detect Wnt antagonists (e.g., OMP-18R5 or OMP-54F28) or control agents present in the tumor biopsy. Furthermore antibodies that detect different tumor and tumor-recruited cell types such as, for example, anti-VE cadherin (CD144) or anti-PECAM-1 (CD31) antibodies to detect vascular endothelial cells, anti-smooth muscle alpha-actin antibodies to detect vascular smooth muscle cells, anti-Ki67 antibodies to detect proliferating cells, TUNEL assays to detect dying cells, anti-β-catenin antibodies to detect Wnt signaling, and anti-intracellular domain (ICD) Notch fragment antibodies to detect Notch signaling can be used to assess the effects of Wnt antagonist (e.g., OMP-18R5 or OMP-54F28) treatment on, for example, angiogenesis, tumor growth and tumor morphology. 
     In certain embodiments, the effect of Wnt antagonist (e.g., OMP-18R5 or OMP-54F28) treatment on neuroendocrine tumor cell gene expression is also assessed. Total RNA is extracted from a portion of each harvested neuroendocrine tumor from Wnt antagonist (e.g., OMP-18R5 or OMP-54F28) treated and control antibody treated mice and used for quantitative RT-PCR. Expression levels of FZD receptors, components of Wnt signaling pathway including, for example, Wnt1 and β-catenin, as well as additional cancer stem cell markers previously identified (e.g. CD44) are analyzed relative to the housekeeping gene GAPDH as an internal control. Changes in neuroendocrine tumor cell gene expression upon treatment with Wnt antagonists (e.g., OMP-18R5 or OMP-54F28) are thus determined. 
     In addition, the effect of Wnt antagonist (e.g., OMP-18R5 or OMP-54F28) treatment on the frequency of cancer stem cells in a neuroendocrine tumor is assessed. Neuroendocrine tumor samples from Wnt antagonist (e.g., OMP-18R5 or OMP-54F28) versus control agent treated mice are cut up into small pieces, minced completely using sterile blades, and single cell suspensions obtained by enzymatic digestion and mechanical disruption. Dissociated neuroendocrine tumor cells are then analyzed by FACS analysis for the presence of tumorigenic cancer stem cells based on ESA+, CD44+, CD24-/low, Lin-surface cell marker expression as described in detail above. 
     The tumorigenicity of cells isolated based on ESA+, CD44+, CD24-/low, Lin-expression following Wnt antagonist (e.g., OMP-18R5 or OMP-54F28) treatment can then assessed. ESA+, CD44+, CD24-/low, Lin-cancer stem cells isolated from Wnt antagonist (e.g., OMP-18R5 or OMP-54F28) treated versus control agent treated mice are re-injected subcutaneously into the mammary fat pads of NOD/SCID mice. The tumorigenicity of cancer stem cells based on the number of injected cells required for consistent neuroendocrine tumor formation is then determined. 
     Example 4 
     Treatment of Human Neuroendocrine Tumor Using Anti-FZD Receptor Antibodies or Soluble FZD Receptors 
     This example describes certain methods for treating neuroendocrine tumor using antibodies against a FZD receptor to target neuroendocrine tumors comprising cancer stem cells and/or tumor cells in which FZD receptor expression has been detected and/or tumor cells having a Wnt gene signature indicating that they are responsive to inhibition of Wnt signaling. 
     In some embodiments, the presence of cancer stem cell marker or FZD receptor or the expression of one or more genes in a Wnt gene signature can first be determined from a tumor biopsy. Tumor cells from a biopsy from a patient diagnosed with neuroendocrine tumor are removed under sterile conditions. In some embodiments the tissue biopsy is fresh-frozen in liquid nitrogen, embedded in OCT., and cut on a cryostat as 10 μm sections onto glass slides. In some embodiments, the tissue biopsy is formalin-fixed, paraffin-embedded, and cut on a microtome as 10um section onto glass slides. 
     Sections are incubated with antibodies against a FZD receptor to detect FZD protein expression. Alternatively, sections can be analyzed for the presence of one or more genes in the Wnt gene signature. 
     The presence of cancer stem cells also may be determined. Tissue biopsy samples are cut up into small pieces, minced completely using sterile blades, and cells subject to enzymatic digestion and mechanical disruption to obtain a single cell suspension. Dissociated neuroendocrine tumor cells are then incubated with anti-ESA, -CD44, -CD24, -Lin, and -FZD antibodies to detect cancer stem cells, and the presence of ESA+, CD44+, CD24-/low, Lin-, FZD+tumor stem cells is determined by flow cytometry as described in detail above. 
     Cancer patients whose neuroendocrine tumors are diagnosed as expressing a FZD receptor and/or one or more genes in the Wnt gene signature are treated with anti-FZD receptor antibodies or soluble FZD receptors. In certain embodiments, humanized or human monoclonal anti-FZD receptor antibodies or soluble FZD receptors are purified and formulated with a suitable pharmaceutical vehicle for injection. In some embodiments, patients are treated with the FZD antibodies or soluble FZD receptors at least once a month for at least 10 weeks. In some embodiments, patients are treated with the FZD antibodies or soluble FZD receptors at least once a week for at least about 14 weeks. Each administration of the antibody or soluble FZD receptors should be a pharmaceutically effective dose. In some embodiments, between about 2 to about 100 mg/ml of an anti-FZD antibody or soluble FZD receptors is administered. In some embodiments, between about 5 to about 40 mg/ml of an anti-FZD antibody or soluble FZD receptors is administered. The antibody or soluble FZD receptors can be administered prior to, concurrently with, or after standard radiotherapy regimens or chemotherapy regimens using one or more chemotherapeutic agent. Patients are monitored to determine whether such treatment has resulted in an anti-tumor response, for example, based on tumor regression, reduction in the incidences of new tumors, lower tumor antigen expression, decreased numbers of cancer stem cells, or other means of evaluating disease prognosis. 
     All publications, patents, patent applications, internet sites, and accession numbers/database sequences (including both polynucleotide and polypeptide sequences) cited herein, as well as U.S. Ser. No. 61/717,294, filed Oct. 23, 2012, are hereby incorporated by reference in their entirety for all purposes to the same extent as if each individual publication, patent, patent application, internet site, or accession number/database sequence were specifically and individually indicated to be so incorporated by reference. 
     
       
         
           
               
             
               
                   
               
               
                 SEQUENCES 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
            
               
                 Human FZD1 full length amino acid sequence  
               
               
                 (SEQ ID NO: 1; underlining indicates ECD): 
               
               
                 
                   MAEEEAPKKSRAAGGGASWELCAGALSARLAEEGSGDAGGRRRPPVDPRR 
                 
               
               
                 
                   LARQLLLLLWLLEAPLLLGVRAQAAGQGPGQGPGPGQQPPPPPQQQQSGQ 
                 
               
               
                 
                   QYNGERGISVPDHGYCQPISIPLCTDIAYNQTIMPNLLGHTNQEDAGLEV 
                 
               
               
                 
                   HQFYPLVKVQCSAELKFFLCSMYAPVCTVLEQALPPCRSLCERARQGCEA 
                 
               
               
                 
                   LMNKFGFQWPDTLKCEKFPVHGAGELCVGQNTSDKGTPTPSLLPEFWTSN 
                 
               
               
                 
                   PQHGGGGHRGGFPGGAGASERGKFSCPRALKVPSYLNYHFLGEKDCGAPC 
                 
               
               
                   EPTKVYGLMYFGPEELRFSRT WIGIWSVLCCASTLFTVLTYLVDMRRFSY 
               
               
                 PERPIIFLSGCYTAVAVAYIAGFLLEDRVVCNDKFAEDGARTVAQGTKKE 
               
               
                 GCTILFMMLYFFSMASSIWWVILSLTWFLAAGMKWGHEATEANSQYFHLA 
               
               
                 AWAVPAIKTITILALGQVDGDVLSGVCFVGLNNVDALRGFVLAPLFVYLF 
               
               
                 IGTSFLLAGFVSLFRIRTIMKHDGTKTEKLEKLMVRIGVFSVLYTVPATI 
               
               
                 VIACYFYEQAFRDQWERSWVAQSCKSYAIPCPHLQAGGGAPPHPPMSPDF 
               
               
                 TVFMIKYLMTLIVGITSGFWIWSGKTLNSWRKFYTRLTNSKQGETTV 
               
               
                   
               
               
                 Human FZD2 full length amino acid sequence  
               
               
                 (SEQ ID NO: 2; underlining indicates ECD): 
               
               
                 
                   MRPRSALPRLLLPLLLLPAAGPAQFHGEKGISIPDHGFCQPISIPLCTDI 
                 
               
               
                 
                   AYNQTIMPNLLGHTNQEDAGLEVHQFYPLVKVQCSPELRFFLCSMYAPVC 
                 
               
               
                 
                   TVLEQAIPPCRSICERARQGCEALMNKFGFQWPERLRCEHFPRHGAEQIC 
                 
               
               
                 
                   VGQNHSEDGAPALLTTAPPPGLQPGAGGTPGGPGGGGAPPRYATLEHPFH 
                 
               
               
                 
                   CPRVLKVPSYLSYKFLGERDCAAPCEPARPDGSMFFSQEETRFARLWILT 
                 
               
               
                 WSVLCCASTFFTVTTYLVDMQRFRYPERPIIFLSGCYTMVSVAYIAGFVL 
               
               
                 QERVVCNERFSEDGYRTVVQGTKKEGCTILFMMLYFFSMASSIWWVILSL 
               
               
                 TWFLAAGMKWGHEATEANSQYFHLAAWAVPAVKTITILAMGQIDGDLLSG 
               
               
                 VCFVGLNSLDPLRGFVLAPLFVYLFIGTSFLLAGFVSLFRIRTIMKHDGT 
               
               
                 KTEKLERLMVRIGVFSVLYTVPATIVIACYFYEQAFREHWERSWVSQHCK 
               
               
                 SLAIPCPAHYTPRMSPDFTVYMIKYLMTLIVGITSGFWIWSGKTLHSWRK 
               
               
                 FYTRLTNSRHGETTV 
               
               
                   
               
               
                 Human FZD3 full length amino acid sequence  
               
               
                 (SEQ ID NO: 3): 
               
               
                 
                   MAMTWIVFSLWPLTVFMGHIGGHSLFSCEPITLRMCQDLPYNTTFMPNLL 
                 
               
               
                 
                   NHYDQQTAALAMEPFHPMVNLDCSRDFRPFLCALYAPICMEYGRVTLPCR 
                 
               
               
                 
                   RLCQRAYSECSKLMEMFGVPWPEDMECSRFPDCDEPYPRLVDLNLAGEPT 
                 
               
               
                 
                   EGAPVAVQRDYGFWCPRELKIDPDLGYSFLHVRDCSPPCPNMYFRREELS 
                 
               
               
                   FARY FIGLISIICLSATLFTFLTFLIDVTRFRYPERPIIFYAVCYMMVSL 
               
               
                 IFFIGFLLEDRVACNASIPAQYKASTVTQGSHNKACTMLFMILYFFTMAG 
               
               
                 SVWWVILTITWFLAAVPKWGSEATEKKALLFHASAWGIPGILTIILLAMN 
               
               
                 KIEGDNISGVCFVGLYDVDALRYFVLAPLCLYVVVGVSLLLAGIISLNRV 
               
               
                 RIEIPLEKENQDKLVKFMIRIGVFSILYLVPLLVVIGCYFYEQAYRGIWE 
               
               
                 TTWIQERCREYHIPCPYQVTQMSRPDLILFLMKYLMALIVGIPSVFWVGS 
               
               
                 KKTCFEWASFFHGRRKKEIVNESRQVLQEPDFAQSLLRDPNTPIIRKSRG 
               
               
                 TSTQGTSTHASSTQLAMVDDQRSKAGSIHSKVSSYHGSLHRSRDGRYTPC 
               
               
                 SYRGMEERLPHGSMSRLTDHSRHSSSHRLNEQSRHSSIRDLSNNPMTHIT 
               
               
                 HGTSMNRVIEEDGTSA 
               
               
                   
               
               
                 Human FZD4 full length amino acid sequence  
               
               
                 (SEQ ID NO: 4): 
               
               
                 
                   MLAMAWRGAGPSVPGAPGGVGLSLGLLLQLLLLLGPARGFGDEEERRCDP 
                 
               
               
                 
                   IRISMCQNLGYNVTKMPNLVGHELQTDAELQLTTFTPLIQYGCSSQLQFF 
                 
               
               
                 
                   LCSVYVPMCTEKINIPIGPCGGMCLSVKRRCEPVLKEFGFAWPESLNCSK 
                 
               
               
                 
                   FPPQNDHNHMCMEGPGDEEVPLPHKTPIQPGEECHSVGTNSDQYIWVKRS 
                 
               
               
                   LNCVLKCGYDAGLYSRSAKEFTDI WMAVWASLCFISTAFTVLTFLIDSSR 
               
               
                 FSYPERPIIFLSMCYNIYSIAYIVRLTVGRERISCDFEEAAEPVLIQEGL 
               
               
                 KNIGCATIFLLMYFFGMASSIWWVILTLTWFLAAGLKWGHEATEMHSSYF 
               
               
                 HIAAWAIPAVKTIVILIMRLVDADELTGLCYVGNQNLDALTGFVVAPLFT 
               
               
                 YLVIGTLFIAAGLVALFKIRSNLQKDGTKTDKLERLMVKIGVFSVLYTVP 
               
               
                 ATCVIACYFYEISNWALFRYSADDSNMAVEMLKIFMSLLVGITSGMWIWS 
               
               
                 AKTLHTWQKCSNRLVNSGKVKREKRGNGWVKPGKGSETV 
               
               
                   
               
               
                 Human FZD5 full length amino acid sequence  
               
               
                 (SEQ ID NO: 5; underlining indicates ECD): 
               
               
                 
                   MARPDPSAPPSLLLLLLAQLVGRAAAASKAPVCQEITVPMCRGIGYNLTH 
                 
               
               
                 
                   MPNQFNHDTQDEAGLEVHQFWPLVEIQCSPDLRFFLCSMYTPICLPDYHK 
                 
               
               
                 
                   PLPPCRSVCERAKAGCSPLMRQYGFAWPERMSCDRLPVLGRDAEVLCMDY 
                 
               
               
                 
                   NRSEATTAPPRPFPAKPTLPGPPGAPASGGECPAGGPFVCKCREPFVPIL 
                 
               
               
                   KESHPLYNKVRTGQVPNCAVPCYQPSFSADERT FATFWIGLWSVLCFIST 
               
               
                 STTVATFLIDMERFRYPERPIIFLSACYLCVSLGFLVRLVVGHASVACSR 
               
               
                 EHNHIHYETTGPALCTIVFLLVYFFGMASSIWWVILSLTWFLAAGMKWGN 
               
               
                 EATAGYAQYFHLAAWLIPSVKSITALALSSVDGDPVAGICYVGNQNLNSL 
               
               
                 RGFVLGPLVLYLLVGTLFLLAGFVSLFRIRSVIKQGGTKTDKLEKLMIRI 
               
               
                 GIFTLLYTVPASIVVACYLYEQHYRESWEAALICACPGHDTGQPRAKPEY 
               
               
                 WVLMLKYFMCLVVGITSGVWIWSGKIVESWRRFTSRCCCRPRRGHKSGGA 
               
               
                 MAAGDYPEASAALTGRTGPPGPAATYHKQVSLSHV 
               
               
                   
               
               
                 Human FZD6 full length amino acid sequence  
               
               
                 (SEQ ID NO: 6; underlining indicates ECD): 
               
               
                 
                   MEMFTFLLTCIFLPLLRGHSLFTCEPITVPRCMKMAYNMTFFPNLMGHYD 
                 
               
               
                 
                   QSIAAVEMEHFLPLANLECSPNIETFLCKAFVPTCIEQIHVVPPCRKLCE 
                 
               
               
                 
                   KVYSDCKKLIDTFGIRWPEELECDRLQYCDETVPVTFDPHTEFLGPQKKT 
                 
               
               
                 
                   EQVQRDIGFWCPRHLKTSGGQGYKFLGIDQCAPPCPNMYFKSDELEFAKS 
                 
               
               
                   FIGTVSI FCLCATLFTFLTFLIDVRRFRYPERPITYYSVCYSIVSLMYFI 
               
               
                 GFLLGDSTACNKADEKLELGDTVVLGSQNKACTVLFMLLYFFTMAGTVWW 
               
               
                 VILTITWFLAAGRKWSCEATEQKAVWFHAVAWGTPGFLTVMLLAMNKVEG 
               
               
                 DNISGVCFVGLYDLDASRYFVLLPLCLCVFVGLSLLLAGIISLNHVRQVI 
               
               
                 QHDGRNQEKLKKFMIRIGVFSGLYLVPLVILLGCYVYEQVNRITWEITWV 
               
               
                 SDHCRQYHIPCPYQAKAKARPELALFMIKYLMTLIVGISAVFWVGSKKTC 
               
               
                 TEWAGFFKRNRKRDPISESRRVLQESCEFFLKHNSKVKHKKKHYKPSSHK 
               
               
                 LKVISKSMGTSTGATANHGTSAVAITSHDYLGQETLTEIQTSPETSMREV 
               
               
                 KADGASTPRLREQDCGEPASPAASISRLSGEQVDGKGQAGSVSESARSEG 
               
               
                 RISPKSDITDTGLAQSNNLQVPSSSEPSSLKGSTSLLVHPVSGVRKEQGG 
               
               
                 GCHSDT 
               
               
                   
               
               
                 Human FZD7 full length amino acid sequence  
               
               
                 (SEQ ID NO: 7; ECD is underlined): 
               
               
                 
                   MRDPGAAAPLSSLGLCALVLALLGALSAGAGAQPYHGEKGISVPDHGFCQ 
                 
               
               
                 
                   PISIPLCTDIAYNQTILPNLLGHTNQEDAGLEVHQFYPLVKVQCSPELRF 
                 
               
               
                 
                   FLCSMYAPVCTVLDQAIPPCRSLCERARQGCEALMNKFGFQWPERLRCEN 
                 
               
               
                 
                   FPVHGAGEICVGQNTSDGSGGPGGGPTAYPTAPYLPDLPFTALPPGASDG 
                 
               
               
                 
                   RGRPAFPFSCPRQLKVPPYLGYRFLGERDCGAPCEPGRANGLMYFKEEER 
                 
               
               
                   RFARL WVGVWSVLCCASTLFTVLTYLVDMRRFSYPERPIIFLSGCYFMVA 
               
               
                 VAHVAGFLLEDRAVCVERFSDDGYRTVAQGTKKEGCTILFMVLYFFGMAS 
               
               
                 SIWWVILSLTWFLAAGMKWGHEATEANSQYFHLAAWAVPAVKTITILAMG 
               
               
                 QVDGDLLSGVCYVGLSSVDALRGFVLAPLFVYLFIGTSFLLAGFVSLFRI 
               
               
                 RTIMKHDGTKTEKLEKLMVRIGVFSVLYTVPATIVLACYFYEQAFREHWE 
               
               
                 RTWLLQTCKSYAVPCPPGHFPPMSPDFTVFMIKYLMTMIVGITTGFWIWS 
               
               
                 GKTLQSWRRFYHRLSHSSKGETAV 
               
               
                   
               
               
                 Human FZD8 full length amino acid sequence  
               
               
                 (SEQ ID NO: 8; ECD is underlined): 
               
               
                 
                   MEWGYLLEVTSLLAALALLQRSSGAAAASAKELACQEITVPLCKGIGYNY 
                 
               
               
                 
                   TYMPNQFNHDTQDEAGLEVHQFWPLVEIQCSPDLKFFLCSMYTPICLEDY 
                 
               
               
                 
                   KKPLPPCRSVCERAKAGCAPLMRQYGFAWPDRMRCDRLPEQGNPDTLCMD 
                 
               
               
                 
                   YNRTDLTTAAPSPPRRLPPPPPGEQPPSGSGHGRPPGARPPHRGGGRGGG 
                 
               
               
                 
                   GGDAAAPPARGGGGGGKARPPGGGAAPCEPGCQCRAPMVSVSSERHPLYN 
                 
               
               
                   RVKIGQIANCALPCHNPFFSQDERAFT VFWIGLWSVLCFVSTFATVSTFL 
               
               
                 IDMERFKYPERPIIFLSACYLFVSVGYLVRLVAGHEKVACSGGAPGAGGA 
               
               
                 GGAGGAAAGAGAAGAGAGGPGGRGEYEELGAVEQHVRYETTGPALCTVVF 
               
               
                 LLVYFFGMASSIWWVILSLTWFLAAGMKWGNEATAGYSQYFHLAAWLVPS 
               
               
                 VKSIAVLALSSVDGDPVAGICYVGNQSLDNLRGFVLAPLVIYLFIGTMFL 
               
               
                 LAGFVSLFRIRSVIKQQDGPTKTHKLEKLMIRLGLFTVLYTVPAAVVVAC 
               
               
                 LFYEQHNRPRWEATHNCPCLRDLQPDQARRPDYAVFMLKYFMCLVVGITS 
               
               
                 GVWVWSGKTLESWRSLCTRCCWASKGAAVGGGAGATAAGGGGGPGGGGGG 
               
               
                 GPGGGGGPGGGGGSLYSDVSTGLTWRSGTASSVSYPKQMPLSQV 
               
               
                   
               
               
                 Human FZD9 full length amino acid sequence  
               
               
                 (SEQ ID NO: 9): 
               
               
                 
                   MAVAPLRGALLLWQLLAAGGAALEIGRFDPERGRGAAPCQAVEIPMCRGI 
                 
               
               
                 
                   GYNLTRMPNLLGHTSQGEAAAELAEFAPLVQYGCHSHLRFFLCSLYAPMC 
                 
               
               
                 
                   TDQVSTPIPACRPMCEQARLRCAPIMEQFNFGWPDSLDCARLPTRNDPHA 
                 
               
               
                 
                   LCMEAPENATAGPAEPHKGLGMLPVAPRPARPPGDLGPGAGGSGTCENPE 
                 
               
               
                   KFQYVEKSRSCAPRCGPGVEVFWSRRDKDF ALVWMAVWSALCFFSTAFTV 
               
               
                 LTFLLEPHRFQYPERPIIFLSMCYNVYSLAFLIRAVAGAQSVACDQEAGA 
               
               
                 LYVIQEGLENTGCTLVFLLLYYFGMASSLWWVVLTLTWFLAAGKKWGHEA 
               
               
                 TEAHGSYFHMAAWGLPALKTIVILTLRKVAGDELTGLCYVASTDAAALTG 
               
               
                 FVLVPLSGYLVLGSSFLLTGFVALFHIRKIMKTGGTNTEKLEKLMVKIGV 
               
               
                 FSILYTVPATCVIVCYVYERLNMDFWRLRATEQPCAAAAGPGGRRDCSLP 
               
               
                 GGSVPTVAVFMLKIFMSLVVGITSGVWVWSSKTFQTWQSLCYRKIAAGRA 
               
               
                 RAKACRAPGSYGRGTHCHYKAPTVVLHMTKTDPSLENPTHL 
               
               
                   
               
               
                 Human FZD10 full length amino acid sequence  
               
               
                 (SEQ ID NO: 10; ECD is underlined): 
               
               
                 
                   MQRPGPRLWLVLQVMGSCAAISSMDMERPGDGKCQPIEIPMCKDIGYNMT 
                 
               
               
                 
                   RMPNLMGHENQREAATQLHEFAPLVEYGCHGHLRFFLCSLYAPMCTEQVS 
                 
               
               
                 
                   TPIPACRVMCEQARLKCSPIMEQFNFKWPDSLDCRKLPNKNDPNYLCMEA 
                 
               
               
                 
                   PNNGSDEPTRGSGLFPPLFRPQRPHSAQEHPLKDGGPGRGGCDNPGKFHH 
                 
               
               
                   VEKSASCAPLCTPGVDVYWSREDKRFA VVWLAIWAVLCFFSSAFTVLTFL 
               
               
                 IDPARFRYPERPIIFLSMCYCVYSVGYLIRLFAGAESIACDRDSGQLYVI 
               
               
                 QEGLESTGCTLVFLVLYYFGMASSLWWVVLTLTWFLAAGKKWGHEATEAN 
               
               
                 SSYFHLAAWAIPAVKTILILVMRRVAGDELTGVCYVGSMDVNALTGFVLI 
               
               
                 PLACYLVIGTSFILSGFVALFHIRRVMKTGGENTDKLEKLMVRIGLFSVL 
               
               
                 YTVPATCVIACYFYERLNMDYWKILAAQHKCKMNNQTKTLDCLMAASIPA 
               
               
                 VEIFMVKIFMLLVVGITSGMWIWTSKTLQSWQQVCSRRLKKKSRRKPASV 
               
               
                 ITSGGIYKKAQHPQKTHHGKYEIPAQSPTCV 
               
               
                   
               
               
                 Human FZD1 ECD with signal sequence  
               
               
                 (SEQ ID NO: 11): 
               
               
                 MAEEEAPKKSRAAGGGASWELCAGALSARLAEEGSGDAGGRRRPPVDPRR 
               
               
                 LARQLLLLLWLLEAPLLLGVRAQAAGQGPGQGPGPGQQPPPPPQQQQSGQ 
               
               
                 QYNGERGISVPDHGYCQPISIPLCTDIAYNQTIMPNLLGHTNQEDAGLEV 
               
               
                 HQFYPLVKVQCSAELKFFLCSMYAPVCTVLEQALPPCRSLCERARQGCEA 
               
               
                 LMNKFGFQWPDTLKCEKFPVHGAGELCVGQNTSDKGTPTPSLLPEFWTSN 
               
               
                 PQHGGGGHRGGFPGGAGASERGKFSCPRALKVPSYLNYHFLGEKDCGAPC 
               
               
                 EPTKVYGLMYFGPEELRFSRT 
               
               
                   
               
               
                 Human FZD2 ECD with signal sequence  
               
               
                 (SEQ ID NO: 12): 
               
               
                 MRPRSALPRLLLPLLLLPAAGPAQFHGEKGISIPDHGFCQPISIPLCTDI 
               
               
                 AYNQTIMPNLLGHTNQEDAGLEVHQFYPLVKVQCSPELRFFLCSMYAPVC 
               
               
                 TVLEQAIPPCRSICERARQGCEALMNKFGFQWPERLRCEHFPRHGAEQIC 
               
               
                 VGQNHSEDGAPALLTTAPPPGLQPGAGGTPGGPGGGGAPPRYATLEHPFH 
               
               
                 CPRVLKVPSYLSYKFLGERDCAAPCEPARPDGSMFFSQEETRFARLWILT 
               
               
                   
               
               
                 Human FZD3 ECD with signal sequence  
               
               
                 (SEQ ID NO: 13): 
               
               
                 MAMTWIVFSLWPLTVFMGHIGGHSLFSCEPITLRMCQDLPYNTTFMPNLL 
               
               
                 NHYDQQTAALAMEPFHPMVNLDCSRDFRPFLCALYAPICMEYGRVTLPCR 
               
               
                 RLCQRAYSECSKLMEMFGVPWPEDMECSRFPDCDEPYPRLVDLNLAGEPT 
               
               
                 EGAPVAVQRDYGFWCPRELKIDPDLGYSFLHVRDCSPPCPNMYFRREELS 
               
               
                 FARY 
               
               
                   
               
               
                 Human FZD4 ECD with signal sequence  
               
               
                 (SEQ ID NO: 14): 
               
               
                 MLAMAWRGAGPSVPGAPGGVGLSLGLLLQLLLLLGPARGFGDEEERRCDP 
               
               
                 IRISMCQNLGYNVTKMPNLVGHELQTDAELQLTTFTPLIQYGCSSQLQFF 
               
               
                 LCSVYVPMCTEKINIPIGPCGGMCLSVKRRCEPVLKEFGFAWPESLNCSK 
               
               
                 FPPQNDHNHMCMEGPGDEEVPLPHKTPIQPGEECHSVGTNSDQYIWVKRS 
               
               
                 LNCVLKCGYDAGLYSRSAKEFTDI 
               
               
                   
               
               
                 Human FZD5 ECD with signal sequence  
               
               
                 (SEQ ID NO: 15): 
               
               
                 MARPDPSAPPSLLLLLLAQLVGRAAAASKAPVCQEITVPMCRGIGYNLTH 
               
               
                 MPNQFNHDTQDEAGLEVHQFWPLVEIQCSPDLRFFLCSMYTPICLPDYHK 
               
               
                 PLPPCRSVCERAKAGCSPLMRQYGFAWPERMSCDRLPVLGRDAEVLCMDY 
               
               
                 NRSEATTAPPRPFPAKPTLPGPPGAPASGGECPAGGPFVCKCREPFVPIL 
               
               
                 KESHPLYNKVRTGQVPNCAVPCYQPSFSADERT 
               
               
                   
               
               
                 Human FZD6 ECD with signal sequence  
               
               
                 (SEQ ID NO: 16): 
               
               
                 MEMFTFLLICIFLPLLRGHSLFICEPITVPRCMKMAYNMIFFPNLMGHYD 
               
               
                 QSIAAVEMEHFLPLANLECSPNIETFLCKAFVPTCIEQIHVVPPCRKLCE 
               
               
                 KVYSDCKKLIDTFGIRWPEELECDRLQYCDETVPVTFDPHIEFLGPQKKT 
               
               
                 EQVQRDIGFWCPRHLKTSGGQGYKFLGIDQCAPPCPNMYFKSDELEFAKS 
               
               
                 FIGTVSI 
               
               
                   
               
               
                 Human FZD7 ECD with signal sequence  
               
               
                 (SEQ ID NO: 17): 
               
               
                 MRDPGAAAPLSSLGLCALVLALLGALSAGAGAQPYHGEKGISVPDHGFCQ 
               
               
                 PISIPLCIDIAYNQTILPNLLGHTNQEDAGLEVHQFYPLVKVQCSPELRF 
               
               
                 FLCSMYAPVCIVLDQAIPPCRSLCERARQGCEALMNKFGFQWPERLRCEN 
               
               
                 FPVHGAGEICVGQNTSDGSGGPGGGPTAYPTAPYLPDLPFTALPPGASDG 
               
               
                 RGRPAFPFSCPRQLKVPPYLGYRFLGERDCGAPCEPGRANGLMYFKEEER 
               
               
                 RFARL 
               
               
                   
               
               
                 Human FZD8 ECD with signal sequence  
               
               
                 (SEQ ID NO: 18): 
               
               
                 MEWGYLLEVISLLAALALLQRSSGAAAASAKELACQEITVPLCKGIGYNY 
               
               
                 TYMPNQFNHDTQDEAGLEVHQFWPLVEIQCSPDLKFFLCSMYTPICLEDY 
               
               
                 KKPLPPCRSVCERAKAGCAPLMRQYGFAWPDRMRCDRLPEQGNPDTLCMD 
               
               
                 YNRIDLITAAPSPPRRLPPPPPGEQPPSGSGHGRPPGARPPHRGGGRGGG 
               
               
                 GGDAAAPPARGGGGGGKARPPGGGAAPCEPGCQCRAPMVSVSSERHPLYN 
               
               
                 RVKTGQIANCALPCHNPFFSQDERAFT 
               
               
                   
               
               
                 Human FZD9 ECD with signal sequence  
               
               
                 (SEQ ID NO: 19): 
               
               
                 MAVAPLRGALLLWQLLAAGGAALEIGRFDPERGRGAAPCQAVEIPMCRGI 
               
               
                 GYNLIRMPNLLGHTSQGEAAAELAEFAPLVQYGCHSHLRFFLCSLYAPMC 
               
               
                 IDQVSTPIPACRPMCEQARLRCAPIMEQFNFGWPDSLDCARLPTRNDPHA 
               
               
                 LCMEAPENATAGPAEPHKGLGMLPVAPRPARPPGDLGPGAGGSGICENPE 
               
               
                 KFQYVEKSRSCAPRCGPGVEVFWSRRDKDF 
               
               
                   
               
               
                 Human FZD10 ECD with signal sequence  
               
               
                 (SEQ ID NO: 20): 
               
               
                 MQRPGPRLWLVLQVMGSCAAISSMDMERPGDGKCQPIEIPMCKDIGYNMI 
               
               
                 RMPNLMGHENQREAAIQLHEFAPLVEYGCHGHLRFFLCSLYAPMCTEQVS 
               
               
                 TPIPACRVMCEQARLKCSPIMEQFNFKWPDSLDCRKLPNKNDPNYLCMEA 
               
               
                 PNNGSDEPTRGSGLFPPLFRPQRPHSAQEHPLKDGGPGRGGCDNPGKFHH 
               
               
                 VEKSASCAPLCIPGVDVYWSREDKRFA 
               
               
                   
               
               
                 Human FZD1 Fri domain amino acid sequence (SEQ 
               
               
                 ID NO: 21; amino acids 87-237 of SEQ ID NO: 1): 
               
               
                 QQPPPPPQQQQSGQQYNGERGISVPDHGYCQPISIPLCTDIAYNQTIMPN 
               
               
                 LLGHTNQEDAGLEVHQFYPLVKVQCSAELKFFLCSMYAPVCIVLEQALPP 
               
               
                 CRSLCERARQGCEALMNKFGFQWPDTLKCEKFPVHGAGELCVGQNTSDKG 
               
               
                 T 
               
               
                   
               
               
                 Human FZD2 Fri domain amino acid sequence (SEQ  
               
               
                 ID NO: 22; amino acids 24-159 of SEQ ID NO: 2): 
               
               
                 QFHGEKGISIPDHGFCQPISIPLCTDIAYNQTIMPNLLGHTNQEDAGLEV 
               
               
                 HQFYPLVKVQCSPELRFFLCSMYAPVCIVLEQAIPPCRSICERARQGCEA 
               
               
                 LMNKFGFQWPERLRCEHFPRHGAEQICVGQNHSEDG 
               
               
                   
               
               
                 Human FZD3 Fri domain amino acid sequence (SEQ  
               
               
                 ID NO: 23; amino acids 23-143 of SEQ ID NO: 3): 
               
               
                 HSLFSCEPITLRMCQDLPYNTTFMPNLLNHYDQQTAALAMEPFHPMVNLD 
               
               
                 CSRDFRPFLCALYAPICMEYGRVILPCRRLCQRAYSECSKLMEMFGVPMP 
               
               
                 EDMECSRFPDCDEPYPRLVDL 
               
               
                   
               
               
                 Human FZD4 Fri domain amino acid sequence (SEQ  
               
               
                 ID NO: 24; amino acids 40-170 of SEQ ID NO: 4): 
               
               
                 FGDEEERRCDPIRISMCQNLGYNVTKMPNLVGHELQTDAELQLTTFTPLI 
               
               
                 QYGCSSQLQFFLCSVYVPMCTEKINIPIGPCGGMCLSVKRRCEPVLKEFG 
               
               
                 FAWPESLNCSKFPPQNDHNHMCMEGPGDEEV 
               
               
                   
               
               
                 Human FZD5 Fri domain amino acid sequence (SEQ  
               
               
                 ID NO: 25; amino acids 27-157 of SEQ ID NO: 5): 
               
               
                 ASKAPVCQEITVPMCRGIGYNLTHMPNQFNHDTQDEAGLEVHQFWPLVEI 
               
               
                 QCSPDLRFFLCSMYTPICLPDYHKPLPPCRSVCERAKAGCSPLMRQYGFA 
               
               
                 MPERMSCDRLPVLGRDAEVLCMDYNRSEATT 
               
               
                   
               
               
                 Human FZD6 Fri domain amino acid sequence (SEQ  
               
               
                 ID NO: 26; amino acids 19-146 of SEQ ID NO: 6): 
               
               
                 HSLFICEPITVPRCMKMAYNMIFFPNLMGHYDQSIAAVEMEHFLPLANLE 
               
               
                 CSPNIETFLCKAFVPTCIEQIHVVPPCRKLCEKVYSDCKKLIDTFGIRWP 
               
               
                 EELECDRLQYCDETVPVTFDPHTEFLG 
               
               
                   
               
               
                 Human FZD7 Fri domain amino acid sequence (SEQ  
               
               
                 ID NO: 27; amino acids 33-170 of SEQ ID NO: 7): 
               
               
                 QPYHGEKGISVPDHGFCQPISIPLCTDIAYNQTILPNLLGHTNQEDAGLE 
               
               
                 VHQFYPLVKVQCSPELRFFLCSMYAPVCIVLDQAIPPCRSLCERARQGCE 
               
               
                 ALMNKFGFQWPERLRCENFPVHGAGEICVGQNTSDGSG 
               
               
                   
               
               
                 Human FZD8 Fri domain amino acid sequence (SEQ  
               
               
                 ID NO: 28; amino acids 28-158 of SEQ ID NO: 8): 
               
               
                 ASAKELACQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWPLVE 
               
               
                 IQCSPDLKFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQYGF 
               
               
                 AWPDRMRCDRLPEQGNPDTLCMDYNRIDLIT 
               
               
                   
               
               
                 Human FZD9 Fri domain amino acid sequence (SEQ  
               
               
                 ID NO: 29; amino acids 23-159 of SEQ ID NO: 9): 
               
               
                 LEIGRFDPERGRGAAPCQAVEIPMCRGIGYNLIRMPNLLGHTSQGEAAAE 
               
               
                 LAEFAPLVQYGCHSHLRFFLCSLYAPMCIDQVSTPIPACRPMCEQARLRC 
               
               
                 APIMEQFNFGWPDSLDCARLPTRNDPHALCMEAPENA 
               
               
                   
               
               
                 Human FZD10 Fri domain amino acid sequence (SEQ  
               
               
                 ID NO: 30; amino acids 21-154 of SEQ ID NO: 10): 
               
               
                 ISSMDMERPGDGKCQPIEIPMCKDIGYNMIRMPNLMGHENQREAAIQLHE 
               
               
                 FAPLVEYGCHGHLRFFLCSLYAPMCTEQVSTPIPACRVMCEQARLKCSPI 
               
               
                 MEQFNFKWPDSLDCRKLPNKNDPNYLCMEAPNNG 
               
               
                   
               
               
                 18R5 VH CDR1  
               
               
                 (SEQ ID NO: 31) 
               
               
                 GFTFSHYTLS 
               
               
                   
               
               
                 18R5 VH CDR2  
               
               
                 (SEQ ID NO: 32) 
               
               
                 VISGDGSYTYYADSVKG 
               
               
                   
               
               
                 18R5 VH CDR3  
               
               
                 (SEQ ID NO: 33) 
               
               
                 NFIKYVFAN 
               
               
                   
               
               
                 18R5 VL CDR1  
               
               
                 (SEQ ID NO: 34) 
               
               
                 SGDNIGSFYVH 
               
               
                   
               
               
                 18R5 VL CDR2  
               
               
                 (SEQ ID NO: 35) 
               
               
                 DKSNRPSG 
               
               
                   
               
               
                 18R5 VL CDR3  
               
               
                 (SEQ ID NO: 36) 
               
               
                 QSYANTLSL 
               
               
                   
               
               
                 18R5 VH  
               
               
                 (SEQ ID NO: 37) 
               
               
                 EVQLVESGGGLVQPGGSLRLSCAASGFTFSHYTLSWVRQAPGKGLEWVSV 
               
               
                 ISGDGSYTYYADSVKGRFTISSDNSKNTLYLQMNSLRAEDTAVYYCARNF 
               
               
                 IKYVFANWGQGTLVIVSS 
               
               
                   
               
               
                 18R5 VL  
               
               
                 (SEQ ID NO: 38) 
               
               
                 DIELTQPPSVSVAPGQTARISCSGDNIGSFYVHWYQQKPGQAPVLVIYDK 
               
               
                 SNRPSGIPERFSGSNSGNTAILTISGTQAEDEADYYCQSYANTLSLVEGG 
               
               
                 GIKLIVLG 
               
               
                   
               
               
                 18R5 heavy chain (IgG2) amino acid sequence,  
               
               
                 underlining indicates VH  
               
               
                 (SEQ ID NO: 39) 
               
               
                 MKHLWFFLLLVAAPRWVLS EVQLVESGGGLVQPGGSLRLSCAASGFTFSH   
               
               
                 
                   YTLSWVRQAPGKGLEWVSVISGDGSYTYYADSVKGRFTISSDNSKNTLYL 
                 
               
               
                   QMNSLRAEDTAVYYCARNFIKYVFANWGQGTLVTVSS ASTKGPSVFPLAP 
               
               
                 CSRSTSESTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLY 
               
               
                 SLSSVVTVPSSNFGTQTYTCNVDHKPSNTKVDKTVERKCCVECPPCPAPP 
               
               
                 VAGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVQFNWYVDGVEV 
               
               
                 HNAKTKPREEQFNSTFRVVSVLTVVHQDWLNGKEYKCKVSNKGLPAPIEK 
               
               
                 TISKTKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESN 
               
               
                 GQPENNYKTTPPMLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHN 
               
               
                 HYTQKSLSLSPGK 
               
               
                   
               
               
                 18R5 LIGHT CHAIN light chain (lambda) amino acid  
               
               
                 sequence, underlining indicates VL  
               
               
                 (SEQ ID NO: 40) 
               
               
                 MAWALLLLTLLTQGTGSWA DIELTQPPSVSVAPGQTARISCSGDNIGSFY   
               
               
                 
                   VHWYQQKPGQAPVLVIYDKSNRPSGIPERFSGSNSGNTATLTISGTQAED 
                 
               
               
                   EADYYCQSYANTLSLVEGGGIKLTVL GQPKAAPSVTLFPPSSEELQANKA 
               
               
                 TLVCLISDFYPGAVTVAWKADSSPVKAGVETTTPSKQSNNKYAASSYLSL 
               
               
                 TPEQWKSHRSYSCQVTHEGSTVEKTVAPTECS 
               
               
                   
               
               
                 18R8 VL CDR1  
               
               
                 (SEQ ID NO: 41) 
               
               
                 SGDKLGKKYAS 
               
               
                   
               
               
                 18R8 VL CDR2  
               
               
                 (SEQ ID NO: 42) 
               
               
                 EKDNRPSG 
               
               
                   
               
               
                 18R8 VL CDR3  
               
               
                 (SEQ ID NO: 43) 
               
               
                 SSFAGNSLE 
               
               
                   
               
               
                 18R8 VL  
               
               
                 (SEQ ID NO: 44) 
               
               
                 DIELTQPPSVSVAPGQTARISCSGDKLGKKYASWYQQKPGQAPVLVIYEK 
               
               
                 DNRPSGIPERFSGSNSGNTATLTISGTQAEDEADYYCSSFAGNSLEVFGG 
               
               
                 GTKLTVLG 
               
               
                   
               
               
                 18R8 18R8 light chain (lambda) amino acid 
               
               
                 sequence, underlining indicates VL  
               
               
                 (SEQ ID NO: 45) 
               
               
                 MAWALLLLTLLTQGTGSWA DIELTQPPSVSVAPGQTARISCSGDKLGKKY   
               
               
                 
                   ASWYQQKPGQAPVLVIYEKDNRPSGIPERFSGSNSGNTATLTISGTQAED 
                 
               
               
                   EADYYCSSFAGNSLEVEGGGIKLTVLG QPKAAPSVTLFPPSSEELQANKA 
               
               
                 TLVCLISDFYPGAVTVAWKADSSPVKAGVETTTPSKQSNNKYAASSYLSL 
               
               
                 TPEQWKSHRSYSCQVTHEGSTVEKTVAPTECS 
               
               
                   
               
               
                 44R24 VH CDR1  
               
               
                 (SEQ ID NO: 46) 
               
               
                 GFTFSSYYIT 
               
               
                   
               
               
                 44R24 VH CDR2  
               
               
                 (SEQ ID NO: 47) 
               
               
                 TISYSSSNTYYADSVKG 
               
               
                   
               
               
                 44R24 VH CDR3  
               
               
                 (SEQ ID NO: 48) 
               
               
                 SIVFDY 
               
               
                   
               
               
                 44R24 VL CDR1  
               
               
                 (SEQ ID NO: 49) 
               
               
                 SGDALGNRYVY 
               
               
                   
               
               
                 44R24 VL CDR2  
               
               
                 (SEQ ID NO: 50) 
               
               
                 SG 
               
               
                   
               
               
                 44R24 VL CDR3  
               
               
                 (SEQ ID NO: 51) 
               
               
                 GSWDTRPYPKY 
               
               
                   
               
               
                 44R24 VH  
               
               
                 (SEQ ID NO: 52) 
               
               
                 EVQLVESGGGLVQPGGSLRLSCAASGFIFSSYYITWVRQAPGKGLEWVST 
               
               
                 ISYSSSNTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCARSI 
               
               
                 VEDYWGQGTLVIVSS 
               
               
                   
               
               
                 44R24 VL  
               
               
                 (SEQ ID NO: 53) 
               
               
                 DIELTQPPSVSVAPGQTARISCSGDALGNRYVYWYQQKPGQAPVLVIPSG 
               
               
                 IPERFSGSNSGNTAILTISGTQAEDEADYYCGSWDIRPYPKYVFGGGIKL 
               
               
                 IVLG 
               
               
                 SEQ ID NO: 54 
               
               
                 CPLYFPLYC 
               
               
                   
               
               
                 SEQ ID NO: 55 
               
               
                 CPLVWPLIC 
               
               
                   
               
               
                 SEQ ID NO: 56 
               
               
                 CPLAWPLIC 
               
               
                   
               
               
                 SEQ ID NO: 57 
               
               
                 CPVKYPLVC 
               
               
                   
               
               
                 SEQ ID NO: 58 
               
               
                 CPLRFPLFC 
               
               
                   
               
               
                 SEQ ID NO: 59 
               
               
                 CPLAWPLIC 
               
               
                   
               
               
                 SEQ ID NO: 60 
               
               
                 CPVKFPLYC 
               
               
                   
               
               
                 SEQ ID NO: 61 
               
               
                 CPVNYPLYC 
               
               
                   
               
               
                 SEQ ID NO: 62 
               
               
                 CPVKFPLYC 
               
               
                   
               
               
                 SEQ ID NO: 63 
               
               
                 CPLTYPLYC 
               
               
                   
               
               
                 SEQ ID NO: 64 
               
               
                 CPLRWPLMC 
               
               
                   
               
               
                 SEQ ID NO: 65 
               
               
                 CPLQYPLMC 
               
               
                   
               
               
                 SEQ ID NO: 66 
               
               
                 CPLSFPLYC 
               
               
                   
               
               
                 SEQ ID NO: 67 
               
               
                 CPLNWPLMC 
               
               
                   
               
               
                 SEQ ID NO: 68 
               
               
                 CP(L/V)X(Y/F/W)PL(Y/F/I/V/M)C 
               
               
                   
               
               
                 SEQ ID NO: 69 
               
               
                 DTLSALIERGLM 
               
               
                   
               
               
                 SEQ ID NO: 70 
               
               
                 DVWWLGSTWLKR 
               
               
                   
               
               
                 SEQ ID NO: 71 
               
               
                 FGNYLNDVRFLI 
               
               
                   
               
               
                 SEQ ID NO: 72 
               
               
                 TNLADIAHWISG 
               
               
                   
               
               
                 Minimum FZD and SFRP Fri domain sequences 
               
               
                 h-FZD1 amino acids 116-227  
               
               
                 (SEQ ID NO: 73) 
               
               
                 CQPISIPLCTDIAYNQTIMPNLLGHTNQEDAGLEVHQFYPLVKVQCSAEL 
               
               
                 KFFLCSMYAPVCIVLEQALPPCRSLCERARQGCEALMNKFGFQWPDTLKC 
               
               
                 EKFPVHGAGELC 
               
               
                   
               
               
                 h-FZD2 amino acids 39-150  
               
               
                 (SEQ ID NO: 74) 
               
               
                 CQPISIPLCTDIAYNQTIMPNLLGHTNQEDAGLEVHQFYPLVKVQCSPEL 
               
               
                 RFFLCSMYAPVCIVLEQAIPPCRSICERARQGCEALMNKFGFQWPERLRC 
               
               
                 EHFPRHGAEQIC 
               
               
                   
               
               
                 h-FZD3 amino acids 28-133  
               
               
                 (SEQ ID NO: 75) 
               
               
                 CEPITLRMCQDLPYNTTFMPNLLNHYDQQTAALAMEPFHPMVNLDCSRDF 
               
               
                 RPFLCALYAPICMEYGRVTLPCRRLCQRAYSECSKLMEMFGVPWPEDMEC 
               
               
                 SRFPDC 
               
               
                   
               
               
                 h-FZD4 amino acids 48-161  
               
               
                 (SEQ ID NO: 76) 
               
               
                 CDPIRISMCQNLGYNVIKMPNLVGHELQTDAELQLTIFTPLIQYGCSSQL 
               
               
                 QFFLCSVYVPMCTEKINIPIGPCGGMCLSVKRRCEPVLKEFGFAWPESLN 
               
               
                 CSKFPPQNDHNHMC 
               
               
                   
               
               
                 h-FZD5 amino acids 33-147  
               
               
                 (SEQ ID NO: 77) 
               
               
                 CQEITVPMCRGIGYNLTHMPNQFNHDTQDEAGLEVHQFWPLVEIQCSPDL 
               
               
                 RFFLCSMYTPICLPDYHKPLPPCRSVCERAKAGCSPLMRQYGFAMPERMS 
               
               
                 CDRLPVLGRDAEVLC 
               
               
                   
               
               
                 h-FZD6 amino acids 24-129  
               
               
                 (SEQ ID NO: 78) 
               
               
                 CEPITVPRCMKMAYNMIFFPNLMGHYDQSIAAVEMEHFLPLANLECSPNI 
               
               
                 ETFLCKAFVPTCIEQIHVVPPCRKLCEKVYSDCKKLIDTFGIRWPEELEC 
               
               
                 DRLQYC 
               
               
                   
               
               
                 h-FZD7 amino acids 49-160  
               
               
                 (SEQ ID NO: 79) 
               
               
                 CQPISIPLCTDIAYNQTILPNLLGHTNQEDAGLEVHQFYPLVKVQCSPEL 
               
               
                 RFFLCSMYAPVCIVLDQAIPPCRSLCERARQGCEALMNKFGFQWPERLRC 
               
               
                 ENFPVHGAGEIC 
               
               
                   
               
               
                 h-FZD8 amino acids 35-148  
               
               
                 (SEQ ID NO: 80) 
               
               
                 CQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWPLVEIQCSPDL 
               
               
                 KFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQYGFAWPDRMR 
               
               
                 CDRLPEQGNPDTLC 
               
               
                   
               
               
                 h-FZD9 amino acids 39-152  
               
               
                 (SEQ ID NO: 81) 
               
               
                 CQAVEIPMCRGIGYNLIRMPNLLGHTSQGEAAAELAEFAPLVQYGCHSHL 
               
               
                 RFFLCSLYAPMCIDQVSTPIPACRPMCEQARLRCAPIMEQFNFGWPDSLD 
               
               
                 CARLPTRNDPHALC 
               
               
                   
               
               
                 h-FZD10 amino acids 34-147  
               
               
                 (SEQ ID NO: 82) 
               
               
                 CQPIEIPMCKDIGYNMIRMPNLMGHENQREAAIQLHEFAPLVEYGCHGHL 
               
               
                 RFFLCSLYAPMCTEQVSTPIPACRVMCEQARLKCSPIMEQFNFKWPDSLD 
               
               
                 CRKLPNKNDPNYLC 
               
               
                   
               
               
                 h-SFRP1 amino acids 57-165  
               
               
                 (SEQ ID NO: 83) 
               
               
                 CVDIPADLRLCHNVGYKKMVLPNLLEHETMAEVKQQASSWVPLLNKNCHA 
               
               
                 GTQVFLCSLFAPVCLDRPIYPCRWLCEAVRDSCEPVMQFFGFYWPEMLKC 
               
               
                 DKFPEGDVC 
               
               
                   
               
               
                 h-SFRP2 amino acids 40-152  
               
               
                 (SEQ ID NO: 84) 
               
               
                 CKPIPANLQLCHGIEYQNMRLPNLLGHETMKEVLEQAGAWIPLVMKQCHP 
               
               
                 DTKKFLCSLFAPVCLDDLDETIQPCHSLCVQVKDRCAPVMSAFGFPWPDM 
               
               
                 LECDRFPQDNDLC 
               
               
                   
               
               
                 h-SFRP3 amino acids 35-147  
               
               
                 (SEQ ID NO: 85) 
               
               
                 CEPVRIPLCKSLPWNMTKMPNHLHHSTQANAILAIEQFEGLLGTHCSPDL 
               
               
                 LFFLCAMYAPICTIDFQHEPIKPCKSVCERARQGCEPILIKYRHSWPENL 
               
               
                 ACEELPVYDRGVC 
               
               
                   
               
               
                 h-SFRP4 amino acids 24-136  
               
               
                 (SEQ ID NO: 86) 
               
               
                 CEAVRIPMCRHMPWNITRMPNHLHHSTQENAILAIEQYEELVDVNCSAVL 
               
               
                 RFFFCAMYAPICTLEFLHDPIKPCKSVCQRARDDCEPLMKMYNHSWPESL 
               
               
                 ACDELPVYDRGVC 
               
               
                   
               
               
                 h-SFRP5 amino acids 53-162  
               
               
                 (SEQ ID NO: 87) 
               
               
                 CLDIPADLPLCHTVGYKRMRLPNLLEHESLAEVKQQASSWLPLLAKRCHS 
               
               
                 DIQVFLCSLFAPVCLDRPIYPCRSLCEAVRAGCAPLMEAYGFPWPEMLHC 
               
               
                 HKFPLDNDLC 
               
               
                   
               
               
                 h-ROR1 minimal Fri domain  
               
               
                 (SEQ ID NO: 88) 
               
               
                 CQPYRGIACARFIGNRIVYMESLHMQGEIENQITAAFTMIGISSHLSDKC 
               
               
                 SQFAIPSLCHYAFPYCDETSSVPKPRDLCRDECEILENVLCQTEYIFARS 
               
               
                 NPMILMRLKLPNCEDLPQPE 
               
               
                 SPEAANC 
               
               
                   
               
               
                 h-ROR2 minimal Fri domain  
               
               
                 (SEQ ID NO: 89) 
               
               
                 CQPYRGIACARFIGNRTIYVDSLQMQGEIENRITAAFTMIGISTHLSDQC 
               
               
                 SQFAIPSFCHFVFPLCDARSRIPKPRELCRDECEVLESDLCRQEYTIARS 
               
               
                 NPLILMRLQLPKCEALPMPESPDAANC 
               
               
                   
               
               
                 Human FZD4 Fri domain (predicted signal sequence  
               
               
                 underlined) 
               
               
                 (SEQ ID NO: 90) 
               
               
                   MLAMAWRGAGPSVPGAPGGVGLSLGLLLQLLLLLGPARG FGDEEERRCDP 
               
               
                 IRISMCQNLGYNVTKMPNLVGHELQTDAELQLTTFTPLIQYGCSSQLQFF 
               
               
                 LCSVYVPMCTEKINIPIGPCGGMCLSVKRRCEPVLKEFGFAWPESLNCSK 
               
               
                 FPPQNDHNHMCMEGPGDEEV 
               
               
                   
               
               
                 Human FZD5 Fri domain (predicted signal sequence  
               
               
                 underlined) 
               
               
                 (SEQ ID NO: 91) 
               
               
                   MARPDPSAPPSLLLLLLAQLVGRAAA ASKAPVCQEITVPMCRGIGYNLTH 
               
               
                 MPNQFNHDTQDEAGLEVHQFWPLVEIQCSPDLRFFLCSMYTPICLPDYHK 
               
               
                 PLPPCRSVCERAKAGCSPLMRQYGFAWPERMSCDRLPVLGRDAEVLCMDY 
               
               
                 NRSEATT 
               
               
                   
               
               
                 Human FZD8 Fri domain (predicted signal sequence  
               
               
                 underlined) 
               
               
                 (SEQ ID NO: 92) 
               
               
                   MEWGYLLEVISLLAALALLQRSSGAAA ASAKELACQEITVPLCKGIGYNY 
               
               
                 TYMPNQFNHDTQDEAGLEVHQFWPLVEIQCSPDLKFFLCSMYTPICLEDY 
               
               
                 KKPLPPCRSVCERAKAGCAPLMRQYGFAWPDRMRCDRLPEQGNPDTLCMD 
               
               
                 YNRTDLTT 
               
               
                   
               
               
                 Human IgG1 Fc region  
               
               
                 (SEQ ID NO: 93) 
               
               
                 DKIHTCPPCPAPELLGGPSVFLFPPKPKDILMISRIPEVICVVVDVSHED 
               
               
                 PEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYK 
               
               
                 CKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLICLVK 
               
               
                 GFYPSDIAVEWESNGQPENNYKTIPPVLDSDGSFFLYSKLTVDKSRWQQG 
               
               
                 NVFSCSVMHEALHNHYTQKSLSLSPGK 
               
               
                   
               
               
                 Human IgG1 Fc region  
               
               
                 (SEQ ID NO: 94) 
               
               
                 KSSDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVS 
               
               
                 HEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGK 
               
               
                 EYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLIC 
               
               
                 LVKGFYPSDIAVEWESNGQPENNYKTIPPVLDSDGSFFLYSKLTVDKSRW 
               
               
                 QQGNVFSCSVMHEALHNHYTQKSLSLSPGK 
               
               
                   
               
               
                 Human IgG1 Fc region  
               
               
                 (SEQ ID NO: 95) 
               
               
                 EPKSSDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVD 
               
               
                 VSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLN 
               
               
                 GKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSL 
               
               
                 TCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKS 
               
               
                 RWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 
               
               
                   
               
               
                 Linker  
               
               
                 (SEQ ID NO: 96) 
               
               
                 ESGGGGVT 
               
               
                   
               
               
                 Linker  
               
               
                 (SEQ ID NO: 97) 
               
               
                 LESGGGGVT 
               
               
                   
               
               
                 Linker  
               
               
                 (SEQ ID NO: 98) 
               
               
                 GRAQVT 
               
               
                   
               
               
                 Linker  
               
               
                 (SEQ ID NO: 99) 
               
               
                 WRAQVT 
               
               
                   
               
               
                 Linker  
               
               
                 (SEQ ID NO: 100) 
               
               
                 ARGRAQVT 
               
               
                   
               
               
                 Signal Sequence  
               
               
                 (SEQ ID NO: 101) 
               
               
                 MEWGYLLEVTSLLAALALLQRSSGAAA 
               
               
                   
               
               
                 Signal Sequence  
               
               
                 (SEQ ID NO: 102) 
               
               
                 MEWGYLLEVTSLLAALALLQRSSGALA 
               
               
                   
               
               
                 Signal Sequence  
               
               
                 (SEQ ID NO: 103) 
               
               
                 MEWGYLLEVTSLLAALALLQRSSGVLA 
               
               
                   
               
               
                 Signal Sequence  
               
               
                 (SEQ ID NO: 104) 
               
               
                 MEWGYLLEVTSLLAALLLLQRSPIVHA 
               
               
                   
               
               
                 Signal Sequence  
               
               
                 (SEQ ID NO: 105) 
               
               
                 MEWGYLLEVTSLLAALFLLQRSPIVHA 
               
               
                   
               
               
                 Signal Sequence  
               
               
                 (SEQ ID NO: 106) 
               
               
                 MEWGYLLEVTSLLAALLLLQRSPFVHA 
               
               
                   
               
               
                 Signal Sequence  
               
               
                 (SEQ ID NO: 107) 
               
               
                 MEWGYLLEVTSLLAALLLLQRSPIIYA 
               
               
                   
               
               
                 Signal Sequence  
               
               
                 (SEQ ID NO: 108) 
               
               
                 MEWGYLLEVTSLLAALLLLQRSPIAHA 
               
               
                   
               
               
                 FZD8-Fc amino acid sequence-variant 54F03 (without 
               
               
                 predicted signal sequence; the ″GRA″ linker  
               
               
                 sequence between the FZD8 sequence and the Fc  
               
               
                 sequence of the fusion protein is underlined)  
               
               
                 (SEQ ID NO: 109) 
               
               
                 ASAKELACQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWPLVE 
               
               
                 IQCSPDLKFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQYGF 
               
               
                 AWPDRMRCDRLPEQGNPDTLCMDYNRIDLIT GRA DKTHTCPPCPAPELLG 
               
               
                 GPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN 
               
               
                 AKTKPREEQYNSTYRVVSVLIVLHQDWLNGKEYKCKVSNKALPAPIEKTI 
               
               
                 SKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQ 
               
               
                 PENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHY 
               
               
                 TQKSLSLSPGK 
               
               
                   
               
               
                 FZD8-Fc variants 
               
               
                 FZD8-Fc variant 54F03 amino acid sequence (without 
               
               
                 predicted signal sequence; alternative cleavage)  
               
               
                 (SEQ ID NO: 110) 
               
               
                 AAAASAKELACQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWP 
               
               
                 LVEIQCSPDLKFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQ 
               
               
                 YGFAWPDRMRCDRLPEQGNPDTLCMDYNRTDLTTGRADKTHTCPPCPAPE 
               
               
                 LLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE 
               
               
                 VHNAKTKPREEQYNSTYRVVSVLIVLHQDWLNGKEYKCKVSNKALPAPIE 
               
               
                 KTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWES 
               
               
                 NGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALH 
               
               
                 NHYTQKSLSLSPGK 
               
               
                   
               
               
                 FZD8-Fc variant 54F09 amino acid sequence (without 
               
               
                 predicted signal sequence)  
               
               
                 (SEQ ID NO: 111) 
               
               
                 ASAKELACQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWPLVE 
               
               
                 IQCSPDLKFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQYGF 
               
               
                 AWPDRMRCDRLPEQGNPDTLCMDYNRIDLITAAPSPPDKTHTCPPCPAPE 
               
               
                 LLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE 
               
               
                 VHNAKTKPREEQYNSTYRVVSVLIVLHQDWLNGKEYKCKVSNKALPAPIE 
               
               
                 KTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWES 
               
               
                 NGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALH 
               
               
                 NHYTQKSLSLSPGK 
               
               
                   
               
               
                 FZD8-Fc variant 54F09 amino acid sequence (without 
               
               
                 predicted signal sequence; alternative cleavage)  
               
               
                 (SEQ ID NO: 112) 
               
               
                 AAAASAKELACQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWP 
               
               
                 LVEIQCSPDLKFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQ 
               
               
                 YGFAWPDRMRCDRLPEQGNPDTLCMDYNRTDLTTAAPSPPDKTHTCPPCP 
               
               
                 APELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVD 
               
               
                 GVEVHNAKTKPREEQYNSTYRVVSVLIVLHQDWLNGKEYKCKVSNKALPA 
               
               
                 PIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVE 
               
               
                 WESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE 
               
               
                 ALHNHYTQKSLSLSPGK 
               
               
                   
               
               
                 FZD8-Fc variant 54F15 amino acid sequence (without 
               
               
                 predicted signal sequence)  
               
               
                 (SEQ ID NO: 113) 
               
               
                 ASAKELACQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWPLVE 
               
               
                 IQCSPDLKFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQYGF 
               
               
                 AWPDRMRCDRLPEQGNPDTLCMDYNRIDLITAAPDKTHTCPPCPAPELLG 
               
               
                 GPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN 
               
               
                 AKTKPREEQYNSTYRVVSVLIVLHQDWLNGKEYKCKVSNKALPAPIEKTI 
               
               
                 SKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQ 
               
               
                 PENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHY 
               
               
                 TQKSLSLSPGK 
               
               
                   
               
               
                 FZD8-Fc variant 54F15 amino acid sequence (without 
               
               
                 predicted signal sequence; alternative cleavage)  
               
               
                 (SEQ ID NO: 114) 
               
               
                 AAAASAKELACQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWP 
               
               
                 LVEIQCSPDLKFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQ 
               
               
                 YGFAWPDRMRCDRLPEQGNPDTLCMDYNRTDLTTAAPDKTHTCPPCPAPE 
               
               
                 LLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE 
               
               
                 VHNAKTKPREEQYNSTYRVVSVLIVLHQDWLNGKEYKCKVSNKALPAPIE 
               
               
                 KTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWES 
               
               
                 NGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALH 
               
               
                 NHYTQKSLSLSPGK 
               
               
                   
               
               
                 FZD8-Fc variant 54F16, 54F17, 54F18, 54F23, 54F25, 
               
               
                 54F27, 54F29, 54F31, and 54F34 amino acid sequence  
               
               
                 (without predicted signal sequence)  
               
               
                 (SEQ ID NO: 115) 
               
               
                 ASAKELACQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWPLVE 
               
               
                 IQCSPDLKFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQYGF 
               
               
                 AWPDRMRCDRLPEQGNPDTLCMDYNRIDLTIKSSDKTHTCPPCPAPELLG 
               
               
                 GPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN 
               
               
                 AKTKPREEQYNSTYRVVSVLIVLHQDWLNGKEYKCKVSNKALPAPIEKTI 
               
               
                 SKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQ 
               
               
                 PENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHY 
               
               
                 TQKSLSLSPGK 
               
               
                   
               
               
                 FZD8-Fc variant 54F16 amino acid sequence (without 
               
               
                 predicted signal sequence; alternative cleavage) 
               
               
                 (SEQ ID NO: 116) 
               
               
                 AAAASAKELACQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWP 
               
               
                 LVEIQCSPDLKFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQ 
               
               
                 YGFAWPDRMRCDRLPEQGNPDTLCMDYNRIDLTIKSSDKTHTCPPCPAPE 
               
               
                 LLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE 
               
               
                 VHNAKTKPREEQYNSTYRVVSVLIVLHQDWLNGKEYKCKVSNKALPAPIE 
               
               
                 KTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWES 
               
               
                 NGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALH 
               
               
                 NHYTQKSLSLSPG 
               
               
                   
               
               
                 FZD8-Fc variant 54F19, 54F20, 54F24, 54F26, 54F28, 
               
               
                 54F30, 54F32, 54F34 and 54F35 amino acid sequence  
               
               
                 (without predicted signal sequence)  
               
               
                 (SEQ ID NO: 117) 
               
               
                 ASAKELACQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWPLVE 
               
               
                 IQCSPDLKFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQYGF 
               
               
                 AWPDRMRCDRLPEQGNPDTLCMDYNRIDLITEPKSSDKTHTCPPCPAPEL 
               
               
                 LGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV 
               
               
                 HNAKTKPREEQYNSTYRVVSVLIVLHQDWLNGKEYKCKVSNKALPAPIEK 
               
               
                 TISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESN 
               
               
                 GQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHN 
               
               
                 HYTQKSLSLSPGK 
               
               
                   
               
               
                 FZD8-Fc variant 54F19 amino acid sequence (without 
               
               
                 predicted signal sequence; alternative cleavage)  
               
               
                 (SEQ ID NO: 118) 
               
               
                 ALAASAKELACQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWP 
               
               
                 LVEIQCSPDLKFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQ 
               
               
                 YGFAWPDRMRCDRLPEQGNPDTLCMDYNRIDLITEPKSSDKTHTCPPCPA 
               
               
                 PELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG 
               
               
                 VEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAP 
               
               
                 IEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEW 
               
               
                 ESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEA 
               
               
                 LHNHYTQKSLSLSPGK 
               
               
                   
               
               
                 FZD8-Fc variant 54F20 amino acid sequence (without 
               
               
                 predicted signal sequence; alternative cleavage)  
               
               
                 (SEQ ID NO: 119) 
               
               
                 VLAASAKELACQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWP 
               
               
                 LVEIQCSPDLKFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQ 
               
               
                 YGFAWPDRMRCDRLPEQGNPDTLCMDYNRIDLITEPKSSDKTHTCPPCPA 
               
               
                 PELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG 
               
               
                 VEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAP 
               
               
                 IEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEW 
               
               
                 ESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEA 
               
               
                 LHNHYTQKSLSLSPGK 
               
               
                   
               
               
                 FZD8-Fc variant 54F34 amino acid sequence (without 
               
               
                 predicted signal sequence)  
               
               
                 (SEQ ID NO: 120) 
               
               
                 KELACQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWPLVEIQC 
               
               
                 SPDLKFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQYGFAWP 
               
               
                 DRMRCDRLPEQGNPDTLCMDYNRIDLITEPKSSDKTHTCPPCPAPELLGG 
               
               
                 PSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNA 
               
               
                 KTKPREEQYNSTYRVVSVLIVLHQDWLNGKEYKCKVSNKALPAPIEKTIS 
               
               
                 KAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQP 
               
               
                 ENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYT 
               
               
                 QKSLSLSPGK 
               
               
                   
               
               
                 FZD8-Fc variant 54F33 amino acid sequence (without 
               
               
                 predicted signal sequence) 
               
               
                 (SEQ ID NO: 121) 
               
               
                 KELACQEITVPLCKGIGYNYTYMPNQFNHDTQDEAGLEVHQFWPLVEIQC 
               
               
                 SPDLKFFLCSMYTPICLEDYKKPLPPCRSVCERAKAGCAPLMRQYGFAWP 
               
               
                 DRMRCDRLPEQGNPDTLCMDYNRIDLTIKSSDKIHTCPPCPAPELLGGPS 
               
               
                 VFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKT 
               
               
                 KPREEQYNSTYRVVSVLIVLHQDWLNGKEYKCKVSNKALPAPIEKTISKA 
               
               
                 KGQPREPQVYTLPPSRDELTRNQVSLTCLVKGFYPSDIAVEWESNGQPEN 
               
               
                 NYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQK 
               
               
                 SLSLSPGK 
               
               
                   
               
               
                 h-Wnt1 C-terminal cysteine rich domain  
               
               
                 (aa 288-370) (SEQ ID NO: 122): 
               
               
                 DLVYFEKSPNECTYSGRLGTAGTAGRACNSSSPALDGCELLCCGRGHRTR 
               
               
                 IQRVIERCNCTFHWCCHVSCRNCTHTRVLHECL 
               
               
                   
               
               
                 h-Wnt2 C-terminal cysteine rich domain  
               
               
                 (aa 267-360) (SEQ ID NO: 123): 
               
               
                 DLVYFENSPDYCIRDREAGSLGTAGRVCNLTSRGMDSCEVMCCGRGYDTS 
               
               
                 HVTRMTKCGCKFHWCCAVRCQDCLEALDVHTCKAPKNADWTTAT 
               
               
                   
               
               
                 h-Wnt2b C-terminal cysteine rich domain  
               
               
                 (aa 298-391) (SEQ ID NO: 124): 
               
               
                 DLVYFDNSPDYCVLDKAAGSLGTAGRVCSKTSKGTDGCEIMCCGRGYDTT 
               
               
                 RVTRVTQCECKFHWCCAVRCKECRNTVDVHTCKAPKKAEWLDQT 
               
               
                   
               
               
                 h-Wnt3 C-terminal cysteine rich domain  
               
               
                 (aa 273-355) (SEQ ID NO: 125): 
               
               
                 DLVYYENSPNFCEPNPETGSFGTRDRTCNVTSHGIDGCDLLCCGRGHNTR 
               
               
                 TEKRKEKCHCIFHWCCYVSCQECIRIYDVHTCK 
               
               
                   
               
               
                 h-Wnt3a C-terminal cysteine rich domain  
               
               
                 (aa 270-352) (SEQ ID NO: 126): 
               
               
                 DLVYYEASPNFCEPNPETGSFGTRDRTCNVSSHGIDGCDLLCCGRGHNAR 
               
               
                 AERRREKCRCVFHWCCYVSCQECTRVYDVHTCK 
               
               
                   
               
               
                 h-Wnt7a C-terminal cysteine rich domain  
               
               
                 (aa 267-359) (SEQ ID NO: 127): 
               
               
                 DLVYIEKSPNYCEEDPVIGSVGIQGRACNKTAPQASGCDLMCCGRGYNTH 
               
               
                 QYARVWQCNCKFHWCCYVKCNTCSERTEMYTCK 
               
               
                   
               
               
                 h-Wnt7b C-terminal cysteine rich domain  
               
               
                 (aa 267-349) (SEQ ID NO: 128): 
               
               
                 DLVYIEKSPNYCEEDAATGSVGTQGRLCNRTSPGADGCDTMCCGRGYNTH 
               
               
                 QYTKVWQCNCKFHWCCFVKCNTCSERTEVFTCK 
               
               
                   
               
               
                 h-Wnt8a C-terminal cysteine rich domain  
               
               
                 (aa 248-355) (SEQ ID NO: 129): 
               
               
                 ELIFLEESPDYCTCNSSLGIYGTEGRECLQNSHNTSRWERRSCGRLCTEC 
               
               
                 GLQVEERKTEVISSCNCKFQWCCTVKCDQCRHVVSKYYCARSPGSAQSLG 
               
               
                 RVWFGVYI 
               
               
                   
               
               
                 h-Wnt8b C-terminal cysteine rich domain  
               
               
                 (aa 245-351) (SEQ ID NO: 130): 
               
               
                 ELVHLEDSPDYCLENKTLGLLGTEGRECLRRGRALGRWELRSCRRLCGDC 
               
               
                 GLAVEERRAETVSSCNCKFHWCCAVRCEQCRRRVTKYFCSRAERPRGGAA 
               
               
                 HKPGRKP 
               
               
                   
               
               
                 h-Wnt10a C-terminal cysteine rich domain  
               
               
                 (aa 335-417) (SEQ ID NO: 131): 
               
               
                 DLVYFEKSPDFCEREPRLDSAGTVGRLCNKSSAGSDGCGSMCCGRGHNIL 
               
               
                 RQTRSERCHCRFHWCCFVVCEECRITEWVSVCK 
               
               
                   
               
               
                 h-Wnt10b C-terminal cysteine rich domain  
               
               
                 (aa 307-389) (SEQ ID NO: 132): 
               
               
                 ELVYFEKSPDFCERDPIMGSPGIRGRACNKTSRLLDGCGSLCCGRGHNVL 
               
               
                 RQTRVERCHCRFHWCCYVLCDECKVTEWVNVCK 
               
               
                   
               
               
                 FZD8-Fc variant 54F28 with predicted signal  
               
               
                 sequence underlined  
               
               
                 (SEQ ID NO: 133) 
               
               
                   MEWGYLLEVTSLLAALLLLQRSPFVHA ASAKELACQEITVPLCKGIGYNY 
               
               
                 TYMPNQFNHDTQDEAGLEVHQFWPLVEIQCSPDLKFFLCSMYTPICLEDY 
               
               
                 KKPLPPCRSVCERAKAGCAPLMRQYGFAWPDRMRCDRLPEQGNPDTLCMD 
               
               
                 YNRTDLTTEPKSSDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTP 
               
               
                 EVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLT 
               
               
                 VLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDE 
               
               
                 LTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLY 
               
               
                 SKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK