bluuebunny/crossref_metadata_2025_split huggingface dataset:
C-Myc, but Not Akt, Can Substitute for Notch in Lymphomagenesis.
Authors: Chiang Mark Y , Childs M. Eden , Romany Candice , Shestova Olga , Aster Jon , Pear Warren S. 
Published: October 2019

Abstract
Abstract 7
Notch signaling is activated in ∼70% of human T-cell acute lymphoblastic leukemia/lymphoma (T-ALL) samples and many human and mouse T-ALL cell lines require Notch signals for growth and survival. To gain insight into the role of Notch during induction of T-ALL, we used a fully penetrant, conditional, transgenic KrasG12D mouse model in which ∼80% of T-ALLs acquire activating Notch1 mutations in the endogenous locus. We crossed mice bearing this transgene with Rosa26-DNMAMLf/f mice, which conditionally express the pan-Notch inhibitor DNMAML. T-ALL developed in these mice despite the expression of DNMAML throughout T-cell development. ∼75% of T-ALL tumors acquired activating Notch1 mutations and suppressed expression of DNMAML, which is consistent with frequent “escape” of Notch from inhibition for efficient T-ALL development. We next compared T-ALL cells that lacked DNMAML expression with T-ALL cells that continued to express DNMAML. T-ALL cells lacking DNMAML expressed the direct Notch target c-Myc at higher levels, proliferated at a higher rate, and contained ∼10-fold higher levels of leukemia-initiating cells. Moreover, DNMAML-positive T-ALLs lost DNMAML after transfer into secondary recipients. These data underscore the strong selective pressure for Notch signals during generation and maintenance of T-ALL. We next sought a mechanistic answer for the strong selective pressure for Notch activation. c-Myc and Akt have both been posited to be critical targets of oncogenic Notch signals. To compare the relative contributions of c-Myc and Akt to lymphomagenesis, we overexpressed c-Myc and activated AKT in the KrasG12D-driven mouse model. T-ALLs induced by KrasG12D and Akt acquired activating Notch1 mutations in ∼70% of tumors, which were sensitive to Notch inhibitors (gamma-secretase inhibitors [GSI]). In contrast, T-ALLs induced by KrasG12D and c-Myc did not acquire Notch1 mutations and were resistant to GSI. We conclude that upregulation of c-Myc is sufficient to substitute for Notch in lymphomagenesis, whereas activation of Akt signaling is not. These data identify c-Myc not AKT as the driving force behind Notch-induced lymphomagenesis. These data emphasize the Notch/c-Myc axis as an attractive, rational, therapeutic target in T-ALL.

Disclosures:
No relevant conflicts of interest to declare.
Hodgkin Lymphoma in Adolescents Treated with Adult Protocols: An Analysis From the German Hodgkin Study Group (GHSG).
Authors: Eichenauer Dennis A. , Bredenfeld Henning , Franklin Jeremy , Haverkamp Heinz , Mueller Horst , Eich Hans T. , Mueller Rolf-Peter , Fuchs Michael , Borchmann Peter , Diehl Volker , Engert Andreas 
Published: October 2019

Abstract
Abstract 719

Introduction:
The standard of care for adolescent Hodgkin lymphoma (HL) patients is undefined, particularly the choice between adult and pediatric protocols. We thus analyzed and compared risk factors, outcome and incidence of secondary malignancies in adolescents and young adults treated within study protocols of the German Hodgkin Study Group (GHSG) to evaluate whether adolescents represent a distinct patient group.

Patients and Methods:
3785 patients of all stages treated within the second (HD4-HD6, 1988-1993) and third (HD7-HD9, 1993-1998) trial generation of the GHSG were retrospectively analyzed. 557 patients were adolescents aged 15 to 20 and 3228 patients were young adults aged 21 to 45. Treatment consisted of chemo- and/or radiotherapy.

Results:
The risk factors large mediastinal mass (more than 1/3 of the maximum intrathoracic diameter) and involvement of three or more lymph node areas were more common in adolescents (30.2% vs. 20.9% and 67.7% vs. 58.7%, respectively, p<.001). The incidence of other risk factors did not differ significantly between age groups. With a median follow-up of 81 months for freedom from treatment failure (FFTF) and 85 months for overall survival (OS), FFTF rates in both groups were comparable (p=.305) while adolescents had a superior OS (p=.008). 6-year FFTF estimates were 80.2% and 79.7%, 6-year OS estimates were 93.6% and 90.9% in adolescents and young adults, respectively. Young adults had a higher risk to develop secondary malignancies. Secondary malignancy rates were 1.6% (9 of 557) in adolescents and 3.1% (101 of 3228) in young adults with secondary hematological malignancies (AML/MDS, NHL) representing the majority of cases in both groups (6/9 in adolescents and 55/101 in young adults). Since adolescents differ from young adults in terms of cancer risk in the general population, standardized incidence ratio (SIR) and absolute excess risk (AER) per 100.000 person-years were calculated. The SIR was higher in adolescents (5.56 vs. 4.58) while the AER was higher in young adults (394 vs. 194). However, differences between age groups were not significant for both.

Conclusions:
There are only slight differences between adolescents and young adults regarding risk factors, outcome and incidence of secondary malignancies. Therefore, treatment with adult protocols can be considered effective and safe in adolescent HL patients.

Disclosures:
No relevant conflicts of interest to declare.
Structural Basis for MLL Cxxc Domain Protection against CpG DNA Methylation and the Essential Role of This Function in MLL-AF9 Leukemia.
Authors: Risner Laurie , Cierpicki Tomasz , Grembecka Jolanta , Lukasik Stephen M , Popovic Relja , Shultis David S , Zeleznik-Le Nancy J. , Bushweller John H. 
Published: October 2019

Abstract
Abstract 763
MLL is the target of chromosomal translocations which cause leukemias with poor prognosis. All leukemogenic MLL fusion proteins retain the CXXC domain which binds to nonmethylated CpG DNA. We present the solution structure of the MLL CXXC domain in complex with DNA, showing for the first time how the CXXC domain distinguishes nonmethylated from methylated CpG DNA. Based on the structure, we designed point mutations which disrupt DNA binding. Introduction of these mutations into MLL-AF9 results in increased DNA methylation of specific CpG nucleotides in Hoxa9, increased H3K9 methylation, decreased expression of Hoxa9 locus transcripts, loss of immortalization potential, and inability to induce leukemia in mice. These results establish that DNA binding by the CXXC domain and protection against DNA methylation is essential for MLL fusion leukemia. They also validate this interaction as a potential target for therapeutic intervention.

Disclosures:
No relevant conflicts of interest to declare.
Novel PDGFRA Point Mutations in Hypereosinophilic Syndrome Induce Growth Factor Independence and Leukemia in Vitro and In Vivo.
Authors: Elling Christian , Erben Philipp , Walz Christoph , Frickenhaus Marie , Schemionek Mirle , Stehling Martin , Serve Hubert , Cross Nick C.P. , Berdel Wolfgang , Mueller-Tidow Carsten , Reiter Andreas , Koschmieder Steffen 
Published: October 2019

Abstract
Abstract 767
Considerable progress has been achieved in our understanding of the pathogenesis of hypereosinophilic syndrome (HES) and chronic eosinophilic leukemia (CEL) by identification of constitutively activated tyrosine kinase fusion genes, e.g. FIP1L1-PDGFRA or ETV6-PDGFRB. However, the overall incidence of those fusion genes in HES/CEL is below 15%, and the molecular pathogenesis of the remaining cases remains elusive. We therefore established generic quantitative RT-PCR assays (RQ-PCR) to detect overexpression of 3'-regions of PDGFRA or PDGFRB as a possible indicator of an underlying fusion gene or point mutation. Patients with known fusion genes involving PDGFRA (n=5, 51 patients) or PDGFRB (n=5; 7 patients) showed significantly increased normalized expression levels compared to 191 patients with fusion gene-negative eosinophilia or healthy individuals (PDGFRA/ABL: 0.73 vs. 0.0066 vs. 0.0064, p<0.0001; PDGFRB/ABL: 196 vs. 3.8 vs. 5.85, p<0.0001). In all patients with significantly increased expression levels who were negative for fusion genes, functionally relevant regions of PDGFRA were sequenced. Several novel mutations (R481G, I562M, H570R, M628T, L705P, G729D) as well as a double mutation (H650Q and R748G) were identified. When cloned into 32D cells, M628T, H650Q, and R748G mutants separately induced growth factor-independent proliferation and clonogenic growth, and this was associated with constitutive phosphorylation of downstream targets STAT5, ERK, and AKT. Low doses of imatinib antagonized all of these effects in vitro. M628T and R748G but not H650Q 32D cell mutants induced acute leukemia after injection into congenic C3H/HeJ mice, similar to FIP1L1-PDGFRA. Interestingly, these two mutants showed a significantly higher propensity to invade the lymph nodes than the FIP1L1-PDGFRA fusion. Oral administration of imatinib to injected mice significantly decreased leukemic growth in vivo and significantly prolonged survival of the recipients. In conclusion, we demonstrate that novel point mutations of the PDGFRA gene found in patients with HES/CEL induce growth factor independence and leukemia in vitro and in vivo and suggest that these patients may benefit from treatment with imatinib.
*CE, PE, AR, and SK contributed equally to this work.

Disclosures:
No relevant conflicts of interest to declare.
Impaired Expression of p66Shc, a Novel Regulator of B-Cell Survival, in Chronic Lymphocytic Leukemia.
Authors: Baldari Cosima T. , Capitani Nagaja , Lucherini Orso Maria , Sozzi Elisa , Ferro Micol , Giommoni Nico , Finetti Francesca , De Falco Giulia , Cencini Emanuele , Pelicci Pier Guiseppe , Lauria Francesco , Forconi Francesco 
Published: October 2019

Abstract
Abstract 801
Intrinsic defects in the apoptotic circuitry underlie to a large extent the extended survival of malignant B cells in chronic lymphocytic leukemia (CLL) and are moreover believed to be responsible for their resistance to chemotherapy. We have recently demonstrated that p66Shc, a member of Shc family of protein adapters, acts as a promoter of apoptosis in T cells. Here we show that p66Shc uncouples the B-cell antigen receptor (BCR) from the Erk and Akt dependent survival pathways, thereby enhancing B-cell apoptosis. Expression of p66Shc was found to be profoundly and consistently impaired in CLL B cells compared to peripheral blood B cells form healthy donors. Moreover, significant differences in p66Shc expression were observed in patients with favorable or unfavorable prognosis, classified on the basis of the mutational status of the IGHV genes, with the lowest expression in the unfavorable prognosis group. Analysis of the expression of genes previously implicated in the apoptosis defects of CLL B cells revealed a selective alteration in the balance of pro- and anti-apoptotic members of the Bcl-2 family in these patients. Reconstitution experiments in CLL B cells, as well as data obtained on B cells from p66Shc-/- mice, showed that p66Shc expression correlates with a bias in the Bcl-2 family towards the pro-apoptotic members. Collectively, the data identify p66Shc as a novel regulator of B cell apoptosis which attenuates survival signals emanating from the BCR and modulates expression of the Bcl-2 family. They moreover provide evidence that the defect in p66Shc expression identified in CLL B cells may be causally related to the imbalance towards the anti-apoptotic Bcl-2 family members observed in these cells.

Disclosures:
No relevant conflicts of interest to declare.
Polymorphisms in the CYP450 Genes Influences Regimen Related Toxicity and Outcome in Patients with Beta Thalassaemia Major Undergoing HSCT.
Authors: Balasubramanian Poonkuzhali , Desire Salamun , Mathews Vikram , Lakshmi Kavitha M , Velayudhan Shaji R , George Biju , Viswabandya Auro , Chandy Mammen , Srivastava Alok 
Published: October 2019

Abstract
Abstract 869
Polymorphisms in drug metabolizing enzymes are known to contribute to inter-individual differences in the pharmacokinetics (PK) of the two most commonly used drugs for conditioning for hematopoietic stem cell transplantation (HSCT), busulfan (Bu) and cyclophosphamide (Cy) and their metabolites in plasma. We have previously reported the impact of CYP genes on the PK of Cy, [Blood (ASH Annual Meeting Abstracts), Nov 2004; 104: 99] and the influence of Cy PK on transplant outcome [Blood (ASH Annual Meeting Abstracts), Nov 2004; 104: 1820]. We have now extended this study to evaluate a total of 19 polymorphisms in 11 genes that are known to be involved in the metabolism of Bu and Cy. 180 of the 276 patients with thalassemia major who underwent HSCT between March 1991 and Dec 2008 and for who genomic DNA was available were included in the study. The following polymorphisms were screened using PCR followed by RFLP and/ or gel electrophoresis: GSTA1*B, GSTM1 and GSTT1 deletion, GSTP1*B, CYP2B6*2, *3, *4, *5 and *6, CYP2C9*2, *3 and *4, CYP2C19*2, *3, CYP3A4*1B, CYP3A5*3, *6 and ALDH1A1*2 and ALDH3A1*2. Polymorphism frequencies were associated with regimen related toxicities, other transplant related complications using Fischer's Exact test and Cox-proportional hazard's model.. Significant associations are shown in the Table. On univariate analysis, CYP2B6*4 variant genotype was associated with incidence of hemorrhagic cystitis (HC); CYP2C9*3 variant genotype was associated with the severity of HC; CYP2C19*3 and 2C9*2 genotypes were associated with overall and even-free survival (OS and EFS) and CYP2C9*2 and CYP2C9*3 genotype was associated with transplant related mortality (TRM). Multivariate analyses performed adjusting for known clinical risk factors still showed these genotypes to be significantly associated with outcome parameters. Variant genotypes of polymorphisms that result in decreased metabolism of Cy are protective against regimen related toxicities while these polymorphisms were risk factors for EFS and OS in the present study. This is the first report on the influence of common GST, CYP and ALDH polymorphisms on outcome of HSCT in patients with thalassaemia major. Screening for these polymorphisms in patients with beta thalassaemia undergoing HSCT can help identify patients at higher risk of complications.Table:EndpointGenotypeRelative risk (95% CI)P- value HCCYP2B6*4 variant0.3 (0.13-0.889)0.028 HC grade 1 vs. HC grade 2-4CYP2C9*3 variant0.2 (0.073-0.962)0.043 TRM2C9*2 variant2.7 (1.08-6.77)0.034 2C9*3 variant2.3 (1.0-5.7)0.049 OS and EFS2C19*3 variant3.3 (1.2-9.3)0.018 2C9*2 variant1.3 (0.93-2.03)0.070

Disclosures:
No relevant conflicts of interest to declare.
Racial Differences in the Presentation and Outcomes of Diffuse Large B-Cell Lymphoma in the United States.
Authors: Malik Neha , Shenoy Pareen J. , Bumpers Kevin , Sinha Rajni , Flowers Christopher R. 
Published: October 2019

Abstract
Abstract 898

Background:
Diffuse large B cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma (NHL), and can often be cured with standard chemoimmunotherapy, but there is great heterogeneity in patient outcomes.

Methods:
To examine the baseline characteristics and outcomes in a national cohort of patients(pts) with DLBCL we performed a retrospective cohort analysis of DLBCL cases diagnosed from 1992 to 2005 in 13 Surveillance, Epidemiology and End Results (SEER) registries. International Classification of Diseases for Oncology histology codes 9680, 9684, 9697 were used to identify cases. Cases with known race were grouped into White (W), Black (B), and others (O; Asians or Pacific Islanders, and American Indians or Alaska Natives). Subtype-specific DLBCL incidence rates were calculated for population subgroups according to age, sex, race, registry and time period, expressed as new cases per 100,000 population and age-adjusted to the 2000 US standard population. Incidence rates were compared by sex and by race by computing incidence rate ratios (IRR) and 95% Confidence Intervals (95% CI). Two- and 5-year relative survival rates (RSR) were calculated by actuarial methods.

Results:
Between 1992 and 2005, 34,436 cases of DLBCL were recorded in SEER. Over this period, the incidence of imunoblastic DLBCL decreased from 1.7 to 0.1 cases per 100,000 population while the incidence of DLBCL as a whole remained stable. Incidence rates were higher among W than among B or O pts with DLBCL (IRR W:B 1.52, 95% CI 1.45-1.59, W:O 1.26, 95% CI 1.21-1.31) and among those with immunoblastic DLBCL but not thymic DLBCL. 65% of B pts compared to 37% of W pts presented at age ≤60 years (p<0.001). Among pts with complete staging (n=5,285), 54% of B compared with 47% of W and 41% of O pts presented with stage III/IV disease (W vs. B p=0.05, W vs. O p=0.002). There were no differences in 2-yr RSR by gender. 2-yr RSR rates were 53% for W, 49% for O, and 46% for B pts (W vs. B p=0.02, W vs. O p=0.09), and improved from 1992 to 2001 for all racial groups. 5-yr RSR rates varied by race (46% for W, 47% for O, and 38% for B pts; (W vs. B p=0.02, W vs. O p=0.09) and gender (47% for females and 43% for males; p=0.03) and remained stable from 1992 to 1997.

Conclusions:
These data indicate that B pts present with DLBCL at a younger age, more advanced stage, and have inferior 2-yr and 5-yr RSR. Given the known differences in outcomes for activated B-cell (ABC) and germinal center B-cell DLBCL subtypes, to address these differences in survival it will be necessary for future studies investigating racial disparities in treatment outcomes to ascertain whether there are racial differences in the incidence of ABC DLBCL.

Disclosures:
Flowers: Amos Medical Faculty Development Program grant from the American Society of Hematology/Robert Wood Johnson Foundation: Research Funding.
Cranial Irradiation Does Not Result in Pituitary-Gonadal Axis Dysfunction in Very Long-Term Male Survivors of Childhood Acute Lymphoblastic Leukemia.
Authors: van Casteren Niels J. , Pieters Rob , Dohle Gert , van Baalen Manita , Neggers Sebastian , Van Den Heuvel M.M. 
Published: October 2019

Abstract
Abstract 989
Poster Board I-11

Introduction:
One of the risks of childhood cancer treatment is fertility impairment later in life. In the past a large proportion of children with acute lymphoblastic leukemia (ALL) has received cranial irradiation as part of their treatment. The aim of this study was to evaluate whether cranial irradiation negatively affects pituitary regulated gonadal function in male survivors of childhood ALL.

Patients and Methods:
We examined gonadal function, including Inhibin B, LH, FSH, testosterone, and pituitary axis function by measuring TSH, Free-T4 and IGF-I levels in 89 long-term male survivors of childhood ALL after a median follow-up time of 19 year (range 7-34 years).

Results:
Twenty-nine out of 89 male ALL survivors received cranial irradiation. Inhibin, FSH, LH, Testosterone, testicular volume as well as TSH and Free-T4 levels were not different in the cranial irradiated group as compared to the non-irradiated group (table 1). In contrast, IGF-I levels were significantly lower in the cranial irradiated group. Survivors treated with total body irradiation or testicular irradiation had significantly decreased gonadal function based on hormone levels.

Conclusions:
These data show that, in contrast to the negative influence on the growth hormone axis, cranial radiotherapy as part of ALL treatment does not have a deleterious long-term effect on the hypothalamic–pituitary-gonadal axis or pituitary-thyroid axis.

Disclosures:
No relevant conflicts of interest to declare.
The Influence of Hemophilia on Wound Healing.
Authors: Hoffman Maureane 
Published: October 2019

Abstract
Abstract SCI-21
Hemostasis is considered to be the first phase of wound healing, followed by inflammation, proliferation and remodeling of the reconstituted tissue. However, very little has been written on the overall effect of impaired hemostatic function on wound healing. Our group has studied the effects of hemophilia B and some other coagulation impairments on healing in a mouse skin punch biopsy model. In this model, a defect of the epidermis and dermis must be replaced. Normally a platelet and fibrin clot fills the defect and forms a framework for the repair process. In addition, growth factors and cytokines are released during hemostasis that influence cellular activities necessary for healing. However, hemophilia and other hemostatic defects delay healing and alter the histology of the process. In our punch biopsy model, the epidermal defect is closed in 8 days in wild type mice, and 10 days in hemophilia B (HB) mice. Histologically, the influx of neutrophils and monocytes is delayed and reduced in HB. This finding supports a key role for thrombin and/or fibrin in mediating the inflammatory response. While the ingrowth of fibroblasts and endothelial sprouts (angiogenesis) appears normal in tempo and histology in HB mice, there are greater numbers of new vessels in the granulation tissue iand much greater microvascular bleeding in HB mice. In addition, hematomas are found adjacent to the vessels from which angiogenic vessels sprout. While reconsitution of thrombin generation at the time of wounding restored clot structure and the initial inflammatory influx, it did not prevent later bleeding into the granulation tissue and hematoma formation. In the mouse model, 5 days of hemostatic therapy (replacement or bypassing) were needed to restore normal healing. Thus, we conclude that adequate hemostatic function is required for an extended period of time to assure normal wound healing. Angiogenesis during healing predisposes to bleeding which can lead to a cycle of inflammation, enhanced angiogenesis and recurrent bleeding. A better understanding of the roles played by hemostasis in the subsequent response to injury holds the promise of improving the management of patients with hemophilia, as well as improving tissue recovery after trauma or surgery.

Disclosures
No relevant conflicts of interest to declare.
New Insights into the Biology of Toll-Like Receptors and Inflammasomes.
Authors: Latz Eicke 
Published: October 2019

Abstract
Abstract SCI-23
Innate immunity evolved to recognize microbial infection and to respond to danger signals that appear under disease conditions. The most recently described innate immune receptor family is the Nod-like receptor (NLR) family. The inflammatory cytokines IL-1b and IL-18 are released only upon cleavage by the inflammatory caspase-1. Caspase-1 activity itself is controlled by a cytosolic signaling complex consisting of the NLR member NALP3 and the adapter protein ASC. After activation NALP3, ASC and caspase-1 form a multi-molecular complex termed the NALP3 inflammasome. The NALP3 inflammasome is activated in response to various membrane active bacterial toxins (e.g. nigericin, maitotoxin or gramicidin) or by incubation with crystalline materials (e.g. silica, asbestos, monosodium urate or alum). The mechanisms by which the NALP3 inflammasome is activated by physico-chemical diverse activators are not well understood. We demonstrate that crystals activate the NALP3 inflammasome in a process that requires phagocytosis and crystal uptake leads to lysosomal damage and rupture. Furthermore, sterile lysosomal damage is also sufficient to induce NALP3 activation and inhibition of phagosomal acidification or inhibition or lack of cathepsins impairs NALP3 activation. These results indicate that the NALP3 inflammasome can sense lysosomal damage induced by various means as an endogenous danger signal. Our results demonstrate a novel strategy of immune cells to recognize different classes of stimuli by a common, indirect mechanism. Cytosolic DNA can activate a NALP3 independent yet ASC dependent inflammasome. AIM2, a member of the PYHIN protein family, has a pyrin domain and a HIN200 DNA binding domain. We discovered that AIM2 binds to dsDNA and forms an inflammasome with ASC leading to caspase 1 activation. These pathways are promising new targets for pharmacological inhibitors with broad clinical significance.

Disclosures
No relevant conflicts of interest to declare.