bluuebunny/crossref_metadata_2025_split huggingface dataset:
ROR1 Is Expressed on the Surface of Non-Neoplastic Human B-Lymphocyte Precursors (Hematogones) and on a Subset of B Acute Lymphoblastic Leukemia
Authors: Broome H. Elizabeth , Rassenti Laura Z , Wang Huan-You , Go William Y. , Meyer Lilly , Kipps Thomas J. 
Published: October 2019

Abstract
Abstract 2735
ROR1 is a putative receptor tyrosine kinase that is expressed during embryogenesis, on chronic lymphocytic leukemia (CLL) cells, but not on normal mature lymphocytes, including normal CD5+ B cells (Fukuda et al PNAS 2008; 105:3047). ROR1 binds Wnt5a, and this ligand enhances the survival of CLL cells in vitro, suggesting that ROR1 functionally contributes to leukemogenesis. Additional evidence for the importance of ROR1 function in leukemia is the noted decrease in survival of B acute lymphoblastic leukemia (B-ALL) cells in vitro after RNAi targeting of ROR1 (Tyner et al. PNAS 2009; 106:8695). To further explore the significance of ROR1 in B-ALL, we analyzed 30 cases of B-ALL for surface expression of ROR1 via multiparameter flow cytometry using a fluorochrome-conjugated mAb specific for ROR1. Only two of 30 cases of B-ALL showed uniform surface ROR1 staining with a mean fluorescence intensity (MFI) that was 6.2 or 3.6 times greater than that of B-ALL cells stained with a control mAb. The other 28 B-ALL cases showed a mean MFI ratio of 1.4 (S.D. = 0.4). The two ROR1+ cases shared distinctive immunophenotypic and cytogenetic changes consistent with a more mature B-ALL subtype. We also evaluated marrow from patients recovering from chemotherapy or hematopoietic stem-cell transplantation and found that non-neoplastic B-lymphocyte precursors (BLP, hematogones) also expressed surface ROR1. These BLP were positive for CD10, CD19, CD38, and dim CD45 with variable expression of CD20, CD34, TdT, and cytoplasmic immunoglobulin. While the surface antigen phenotype of B-ALL is similar to BLP, flow cytometry can distinguish B-ALL from BLP because B-ALL shows more uniform antigen expression, lacking the continuum of maturation stages present in BLP. Also, B-ALL usually has aberrant antigen-expression intensity or aberrant antigen co-expression such as terminal deoxynucleotidyl transferase (TdT) plus CD20 on the same cell. Of 22 marrow samples tested with 1–20% hematogones, all had CD10+, CD19+, dim CD45+ cells that expressed ROR1 with a mean MFI ratio of 4.9 (S.D. 2.0). Further study found ROR1 was restricted to a subset of CD10, CD19, and low-level CD45 cells that lack expression of CD34 or TdT. This subset is consistent with an intermediate stage of B-cell maturation, possibly associated with B-lymphoid positive and negative selection. In contrast, CD10+, CD19+ germinal center B cells from reactive lymph nodes were negative for surface ROR1 (N=4). This pattern of ROR1 expression on BLP and a subset of distinctive B-ALL suggests that surface expression of ROR1 occurs during a discrete stage of B-cell maturation in the marrow that may be expanded during recovery from myeloablative therapy and/or hematopoietic stem cell transplantation.

Disclosures:
No relevant conflicts of interest to declare.
Rituximab Treatment In Pediatric Patients with Immunohematologic Diseases Refractory to Convertional Therapy
Authors: Trucco Matteo , O'Riordan Mariann , Berman Brian W. 
Published: October 2019

Abstract
Abstract 2764

Objective:
To evaluate the effectiveness and safety of rituximab in the treatment of antibody mediated hematologic disorders refractory to conventional therapy.

Study Design:
Retrospective chart review of 16 patients treated at Rainbow Babies and Children's Hospital with rituximab for antibody mediated hematologic disorders. Treatment effects and adverse reactions potentially attributed to rituximab therapy were recorded.

Results:
Patients (age range 4 months- 17 years) with the following disorders were included: autoimmune hemolytic anemia (4); chronic immune thrombocytopenia (5); autoimmune pancytopenia (4); hemophilia with inhibitor (2); acquired Factor VIII inhibitor (1). All patients received rituximab at 375mg/m2/dose, after failure to obtain a durable response to conventional therapies. The majority of patients were treated with 4 weekly dose “cycles”. One patient only received 2 doses, and two patients were maintained on prolonged weekly therapy. Two patients showed no clinical or laboratory improvement with rituximab therapy. Two patients initially responded to rituximab therapy, but relapsed 2 months after therapy. Of the remaining patients, 7 had no recurrence of disease by the end of the study period, median follow-up 14months (4mo-72mo). The remaining patients relapsed requiring repeat cycles of rituximab. Median time to relapse was 15 months (13-18mo). The most common adverse reactions were serum sickness (n=3) and hypogammaglobulinemia (n=2). Of the patients who developed hypogammaglobulinemia, one improved after a single infusion of IVIG, the other patient required chronic IVIG infusions. One patient developed chronic sinusitis and one developed acute demylinating encephalomyelitis after receiving rituximab. It is unclear if these illnesses were due to the rituximab or secondary to underlying immune dysfunction.

Conclusions:
Rituximab appears to be effective in a variety of antibody mediated hematologic disorders refractory to more conventional therapies in children and adolescents. The observed adverse reactions were generally mild and self-limited.

Disclosures:
Off Label Use: Rituximab. B cell immununosuppresion.
Isopentenyl Pyrophosphate (IPP), a Metabolite produced in Myeloma Cells Induces the Chemotaxis of γδT Cells
Authors: Ashihara Eishi , Munaka Tatsuya , Kimura Shinya , Kanai Masaki , Abe Hirohisa , Hirai Hideyo , Shoji Shuichi , Maekawa Taira 
Published: October 2019

Abstract
Abstract 2766
γδT cells, which control the innate immune system, are classified into three subtypes on the basis of Vγ chain. Of these subtypes, Vγ2Vδ9 T cells display anti-tumor immunity. We have demonstrated that nitrogen-containing bisphosphonate (N-BP) treatment expands Vγ2Vδ9 T cells ex vivo and that these expanded cells can kill tumor cells in a major histocompatibility complex-unrestricted manner (Sato, Int J Cancer, 2005; Uchida, Biochem Biophys Res Commun, 2007; Sato, Cancer Immunol Immunother, 2008.). N-BP inhibits farnesyl pyrophosphate synthase in the mevalonate pathway, resulting in the accumulation of isopentenyl pyrophosphate (IPP), which is a stimulatory antigen for Vγ2Vδ9T cells. In the present study, we investigated the chemotactic factors for Vγ2Vδ9T cells by using a micro total analysis system-based microfluidic cellular analysis device (Kanai, Sens Actuators A, 2004; Munaka, Analyst, 2007.). This microchip possesses a minute-volume (240 nL) chamber integrated with a micro-sample injector that permits the injection of a small amount (several nL) of a solute (Figure 1). Because of the minute size of this chamber, a concentration gradient can be maintained free from the influence of fluid convection and stirring, and the solute can consequently spread in a diffusion-dependent manner. Therefore, administration of a humoral factor via the sample injector mimics its release from the cell surface. We first investigated whether the supernatant of RPMI8226 multiple myeloma (MM) cells treated with zoledronic acid (ZOL) induced chemotaxis of γδT cells. We treated RPMI8226 MM cells with ZOL (1 mM) overnight and collected the supernatant. Human γδT cells were obtained by the culture of peripheral blood mononuclear cells as previously reported (Uchida, Biochem Biophys Res Commun, 2007.), and these cells were cultured in the microchip. After the injection of supernatant, γδT cells migration was observed under a microscope and continuous time-lapse recording was performed for 30 min. γδT cells migrated toward the injector, indicating that the supernatant of ZOL-treated RPMI8226 cells includes a chemoattractant factor for γδT cells. We next applied soluble MICA (sMICA), sICAM-1, sVCAM-1, and IPP and examined the migration of γδT cells. Among them, sMICA and IPP were chemoattractive for γδT cells, and the velocity of γδT cell migration was increased by the injection of IPP compared to the solvent control (Figure 2). These observations indicate that IPP, a metabolite of the mevalonate pathway in MM cells, or sMICA is a chemotactic factor for γδT cells when the target MM ells are treated with ZOL.

Disclosures:
Munaka: Shimadzu Corporation: Employment. Kanai:Shimadzu Corporation: Employment. Abe:Shimadzu Corporation: Employment.
Resminostat In Relapsed or Refractory Hodgkin Lymphoma: Initial Results of the SAPHIRE Phase II Trial with a Novel Oral Histone Deacetylase (HDAC) Inhibitor.
Authors: Walewski Jan , Paszkiewicz-Kozik Ewa , Borsaru Gabriela , Moicean Andreea , Warszewska Agnieszka , Strobel Klaus , Biggi Alberto , Hauns Bernhard , Mais Anna , Henning Stefan W. , Hentsch Bernd 
Published: October 2019

Abstract
Abstract 2811
Resminostat (4SC-201) is a novel pan-HDAC inhibitor that has shown anti-tumor activity in a broad panel of preclinical models and revealed a very favorable safety and promising efficacy profile in patients with various solid tumor types in an initial Phase I trial. Resminostat is currently under investigation in a number of Phase II clinical trials. The SAPHIRE study evaluates the therapeutic activity of resminostat in relapsed/refractory Hodgkin Lymphoma (HL) patients after high dose chemotherapy and autologous hematopoietic stem cell transplantation. The trial is designed as an open-label, single-arm international trial with a Simon Minimax design. Resminostat is administered orally at a once daily dose of 600 mg in 2-week cycles consisting of 5 consecutive days treatment followed by a 9 day treatment free period. Dose delay and reduction is allowed for management of adverse events. Patients undergo assessment of disease status by computed tomography in combination with positron emission tomography (PET/CT), as recommended by the International Working Group (IWG) criteria for the evaluation of HL. PET/CT scans are conducted after cycle 3 and cycle 6 and thereafter every 4th cycle during an optional follow-up treatment period in which patients may remain on treatment until disease progression or occurrence of intolerance to protocol therapy. The primary endpoint of the study is the estimation of overall objective response rate (OOR), secondary endpoints include time to response (TTR), duration of response (DOR), safety and tolerability and the study of drug regulated biomarkers in this patient cohort. As of July 2010, 19 patients with advanced HL have been enrolled in the 1st Simon stage of the study. Treatment was well tolerated with common related grade 2 –3 AEs being anemia and thrombocytopenia that were well manageable by dose modification or symptomatic treatment. Analysis of PET/CT data through an independent central assessment committee confirmed the achievement of the clinical activity requirements for the advancement of the trial into the 2nd Simon recruitment phase. Updated clinical data of this ongoing study on the efficacy and safety of the HDAC inhibitor resminostat in relapsed/refractory HL patients will be presented at the meeting.

Disclosures:
Walewski: 4SC AG: Consultancy. Warszewska:4SC AG: Consultancy. Strobel:4SC AG: Consultancy. Biggi:4SC AG: Consultancy. Hauns:4SC AG: Employment. Mais:4SC AG: Employment. Henning: 4SC AG: Employment. Hentsch:4SC AG: Employment.
Combination of c-SRC and FLT3 Inhibitors Has An Additive Inhibitory Effect on FLT3 ITD but Not on FLT3 TKD Positive Cells
Authors: Leischner Hannes , Grundler Rebekka , Albers Corinna , Illert Anna Lena , Götze Katharina , Peschel Christian , Duyster Justus 
Published: October 2019

Abstract
Abstract 2892
Activating mutations of FLT3 are frequent in patients with AML. Two types of mutations are most common: Internal tandem duplications (ITD) of the juxtamembrane domain in approximately 30% of patients and point mutations within the second tyrosine kinase domain (TKD) in about 7% of AML patients. Patients carrying the FLT3-ITD mutation have a significantly worse prognosis whereas FLT3-TKD mutations do not appear to influence the clinical outcome. Studies have shown that mice receiving a transplant of bone marrow expressing FLT3 ITD develop a myeloproliferative disease. In contrast, mice which were transplanted with FLT3 TKD infected bone marrow, suffer from a lymphoid disease. Thus, both FLT3 mutations seem to exert different biological functions. Interestingly, FLT3-ITD but not FLT3-TKD or FLT3-WT leads to a strong activation of the STAT5 signaling pathway.
Recently we have shown that c-SRC is the crucial signaling mediator of FLT3 ITD to activate STAT5. Based on these findings we investigated the effect of FLT3 inhibitors (Midostaurin, Sorafenib and Sunitinib) in combination with c-SRC inhibitors (Dasatinib and PD166-326) on FLT3 ITD and FLT3 TKD murine and human cell lines as well as on primary patient material.
In FLT3 ITD expressing murine myeloid 32D cells c-SRC inhibitors in combination with FLT3 inhibitors showed clear additive effects on growth inhibition, apoptosis and activation of STAT5. In contrast, c-SRC inhibitors had no additional effects in FLT3 TKD expressing cells. Accordingly, a strong additive effect of c-SRC and FLT3 inhibitors could also be demonstrated in the FLT3 ITD positive human AML cell line MV4-11. Finally FLT3 ITD and FLT3 TKD positive primary human AML cells were investigated. We were able to detect a significant additional growth inhibition of FLT3 ITD positive human cells by combining c-SRC and FLT3 inhibitors. In contrast, no further growth inhibition was observed by c-SRC inhibition in primary AML cells expressing the FLT3 TKD mutation.
Together our results confirm c-SRC as a crucial signaling mediator in FLT3-ITD but not FLT3-TKD positive AML. The combination of FLT3 and c-SRC inhibitors warrants further investigation in FLT3 ITD positive AML.

Disclosures:
No relevant conflicts of interest to declare.
Identification of Single Nucleotide Polymorphism Interactions Associated with Survival and Risk In Multiple Myeloma Using Novel Data Mining Methods
Authors: Van Ness Brian , Haznadar Majda , Fang Gang , Wang Wen , Paunic Vanja , Steinbach Michael , Kumar Vipin , Day Patrick , David Johnson , Morgan Gareth J , Barlogie Bart , Durie Brian GM 
Published: October 2019

Abstract
Abstract 2973
Disease risk and therapeutic outcomes are impacted by both tumor heterogeneity as well as germline variations found in the population. Multiple myeloma (MM) shows significant heterogeneity in genetic aberrations in tumor cells, that together with inherited polymorphisms, affects disease risk and therapeutic response. In order to identify the impact of genetic variations (SNPs) on MM we have developed a Bank On A Cure platform for examining 3404 SNPs, selected in 983 genes associated with pathways affecting cellular functions important in cancer. Using SNP data sets we sought to identify genetic interactions, beyond single univariate association analysis. The challenge was to use data mining methods that take into account relatively small cohorts of patients, in which false discovery rates typically exceed the power of the study. We report results from using novel computational approaches that efficiently identify higher order SNP interactions associated with disease risk as well as survival outcomes, while minimizing the false discovery rate. The BOAC SNP panel was used to develop a data base on 143 patients selected for short (<1yr) versus long (>3yr) survival in ECOG 9486 and SWOG 9321; as well as 247 newly diagnosed patients and equal number of controls for disease risk analysis. One algorithm developed employs a discriminative pattern mining approach in which defined pathway sets of SNPs are used in combination testing. A second algorithm used identified SNPs that had some association with outcome (survival or disease status); but demonstrated a significant increase in associations when examined in combinations – we refer to this as a p-value jump association. Variations in genes associated with cell cycle, apoptosis, drug metabolism, stress response and immunity reached very low p-values, and survived multiple comparison testing when analyzed in combinations associated with both survival (PFS) predictions as well as analysis of case-control disease risk. Some of the key genetic variations identified in various combinations, included: PTRB, PTEN, CDK5, XRCC4, GSTA4, GPX, DYPD, PCNA, CYP4F2, VEGF, PON1, ALK, and BAG3. The data mining methods and algorithms used, and specific combinations associated with risk and survival, will be presented. These results are being further validated in new cohorts, and functional implications of identified genetic variants are being investigated in HapMap cell lines.

Disclosures:
No relevant conflicts of interest to declare.
An Investigational Proteasome Inhibitor MLN9708 (MLN2238) Induces Apoptosis In Human Multiple Myeloma Cells In Vitro
Authors: Masood Aisha , Chitta Kasyapa , Miles Kiersten M , Khan Nazmul H , Adelaiye Remi , Akhtar Drusilla , Sher Taimur , Chanan-Khan Asher A. 
Published: October 2019

Abstract
Abstract 3066
Targeting the proteasome has proven to be one of the most effective therapeutic strategies in the treatment of multiple myeloma (MM), and the proteasome inhibitor bortezomib is approved for treatment of MM. However its clinical efficacy is compromised by the acquired resistance in patients, necessitating the development of new therapeutics. Several new proteasome inhibitors are under investigation for their therapeutic efficacy in MM. MLN9708 (Millennium Pharmaceuticals, Inc., Cambridge, MA) is a proteasome inhibitor which shows refined pharmacokinetic and pharmacodynamic properties in preclinical studies and is currently in Phase I clinical development. Upon exposure to aqueous solutions or plasma, MLN9708 rapidly hydrolyzes to MLN2238, the biologically active form. MLN2238 was used for all of the studies reported here, in which we report the efficacy of MLN2238 on three established MM cell lines-KMS11, OPM2 and U266. MLN2238 was found to inhibit the chymotrypsin-like proteasomal activity of all MM cell lines in a dose dependent manner. Investigation of the IC50 of MLN2238 on these cell lines demonstrated that KMS11 is the most sensitive (IC50 of 15.9 nM) while U266 was found to be the least sensitive cell line (IC50 of 511 nM). OPM2 cells also showed intermediate sensitivity with an IC50 of 58.6 nM. MLN2238 induced apoptosis in KMS11 cells as evidenced by annexin V staining and PARP-1 cleavage. Cleavage of caspases 9 and 3 suggested activation of the intrinsic apoptotic pathway by MLN2238. Furthermore, MLN2238 treatment was shown to increase the mitochondrial outer membrane permeability (MOMP) and decrease BCL-2 levels. Evaluation of the expression of PSMB5, the preferred proteasomal subunit target for both bortezomib and MLN2238, revealed that it is expressed at approximately 3 fold more in KMS11 cells as compared to U266, suggesting a possible mechanism for higher sensitivity of KMS11 to the proteasomal inhibitor, MLN2238. This preclinical evaluation confirms the anti-myeloma effects of MLN2238, warranting further in-depth evaluation in both in vitro and in vivo models of MM.

Disclosures:
No relevant conflicts of interest to declare.
Primary Myelofibrosis In Children
Authors: DeLario Melissa R. , Sheehan Andrea , Ataya Ramona , Bertuch Alison A. , Vega Carlos , Webb C. Renee , lopez-Terrada Dolores , Venkateswaran Lakshmi 
Published: October 2019

Abstract
Abstract 3079
Primary myelofibrosis is a chronic myeloproliferative disorder characterized by cytopenias, leukoerythroblastosis, extramedullary hematopoiesis, hepatosplenomegaly and bone marrow fibrosis. It is a serious medical condition in adults, often requiring major interventions such as hematopoietic stem cell transplantation (HSCT) for cure. In comparison to adults, children are rarely affected by this entity; the largest case series reports on four such patients. Most of these reports suggest that the majority of affected children have spontaneous resolution of their myelofibrosis with no long term complications. To better describe the clinical characteristics and outcomes of pediatric primary myelofibrosis, we performed a retrospective chart review of children diagnosed with myelofibrosis by bone marrow pathology at our institution from 1996 to 2009. Eighteen patients with primary myelofibrosis were identified. At presentation, all patients had one or more cytopenias and only one had leukoerythroblastosis. Three of 11 patients tested (27%) had cytogenetic abnormalities, as opposed to up to two-thirds of adults with primary myelofibrosis. Eleven of 18 patients (61%) demonstrated erythroid hypoplasia in the bone marrow, which is uncommon in adults. Based on recent molecular studies of myeloproliferative disorders in adults, the World Health Organization now includes the presence of a clonal marker such as JAK2V617F as a major criterion for diagnosis of myelofibrosis in adults. In contrast to approximately half of adults (43-63%) with primary myelofibrosis, JAK2V617F mutation in the bone marrow has not been reported in children. JAK2V617F mutation analysis was negative on 16 of 18 bone marrow specimens tested. In this series, only 5 of the 18 children (27.8%) had spontaneous recovery. No child developed malignant transformation. Eight children underwent HSCT, four of whom were cured of their myelofibrosis; the remaining four children died from infections acquired during transplantation. Four children died prior to transplantation, or were identified as having myelofibrosis at autopsy. One child transferred care to another facility and thus outcome data was not available. In all children, infection was the most common cause of death. Notably, the degree of bone marrow fibrosis did not correlate with outcome. Our series demonstrates that children with primary myelofibrosis have hematologic, bone marrow and molecular features that differ from adults. In contrast to what is found in the literature, our series of pediatric patients with primary myelofibrosis, the largest reported thus far, indicates a poor outcome for the majority of these patients.

Disclosures:
No relevant conflicts of interest to declare.