bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic and Epigenetic Profiling on 7q22 Identifies ATXN7L1 As Candidate Tumor Suppressor in Acute Myelogenous Leukemia
Authors: Poetsch Anna R , Claus Rainer , Bonnet Jacques , Devys Didier , Rücker Frank G. , Tora László , Döhner Konstanze , Döhner Hartmut , Plass Christoph 
Published: October 2019

Abstract
Abstract 1408
About 10 % of patients with acute myeloid leukemia (AML) present with either monosomy 7 or deletions on the long arm of chromosome 7. This chromosomal aberration is associated with poor prognosis and adverse therapeutic response. Following biallelic inactivation as proposed by Knudsen's hypothesis, a “second hit” of the remaining allele might be required for loss of gene function. So far, no consistent additional genetic hits could be identified in the minimally deleted regions. Thus, epigenetic silencing might display a local alternative mechanism ultimately causing silencing of a potential tumor suppressor. Based on cytogenetic data we defined a minimally deleted region on 7q22.2 of 2–3 Mb in size to narrow down the location of the putative tumor suppressor. It is flanked by the microsatellite markers D7S1503 and D7S1841. We utilized comprehensive DNA methylation profiling in the CpGrich areas of the minimal deleted regions by high resolution DNA methylation assessment by MassARRAY to identify aberrant epigenetic patterns in these regions. In this region we quantitatively analyzed CpG island methylation in a cohort of 64 AML patients with del(7q), 11 with monosomy 7, ten with normal karyotype and five CD34+ bone marrow cell DNA from healthy donors as controls. We identified four genes (PRES, LHFPL3, ATXN7L1, and CDH28) that are hypermethylated in their promoters in this region with significant mean methylation differences from 5 to 20 % comparing AML to healthy controls. Hypermethylation occurred both in patients with chromosome 7 aberrations and in patients with normal karyotypes. To narrow down aberrantly methylated genes to functional relevant candidates, we excluded those that were not expressed in healthy CD34+ cells. ATXN7L1, a gene located on 7q22.2 and coding for a potential subunit of the histone acetyl transferase (HAT) and deubiquitinase SAGA complex, was expressed in healthy CD34+ cells and granulocytes, but downregulated upon hypermethylation (>30%) in patients. To elucidate a potential functional role of ATXN7L1, we immunopurified SAGA from HeLa cells using antibodies against a SAGA subunit, GCN5,and analyzed the coimmunoprecipated proteins by subsequent mass spectrometry. Based on the identity of the co-precipitated proteins we demonstrate that ATXN7L1 is a bona fide component of the human SAGA complex. Thus our results suggest that ATXNL1 has a similar role as the closely related protein, ATXN7 that is known to be involved in transcription regulation via USP22 dependent deubiquitination of histones. Experiments to understand how ATXN7L1 silencing may affect the leukemic phenotype are in progress.

Disclosures:
No relevant conflicts of interest to declare.
Impact of Iron Chelation Therapy on Overall Survival and AML Transformation in Lower Risk MDS Patients Treated At the Moffitt Cancer Center
Authors: Komrokji Rami S. , Ali Najla H Al , Padron Eric , Lancet Jeffrey E. , List Alan F. 
Published: October 2019

Abstract
Abstract 2776

Background:
Elevated serum ferritin levels and red blood cell transfusion dependence are associated with poor outcome in patients with lower risk myelodysplastic syndromes (MDS). Few retrospective and observational studies suggest that iron chelation therapy (ICT) may favorably impact outcome in lower risk MDS. The vast majority of patients in those studies were treated with deferoxamine (Desferal). Two studies reported that oral deferasirox (Exjade) significantly decreases ferritin level over time in MDS. An ongoing randomized placebo-controlled trial (TELESTO) is designed to address the impact of deferasirox on overall survival (OS) in lower risk MDS. We examined the impact of ICT predominantly deferasirox in lower risk MDS patients treated at the Moffitt Cancer Center (MCC).

Methods:
Patients were retrospectively identified from the MCC database and individual patients' records reviewed. Inclusion criteria included lower risk MDS patients defined as low or intermediate-1 (int-1) risk disease by the international prognostic scoring system (IPSS) and serum ferritin level ≥ 1000 ng/ml. Patients were divided into two comparator groups: ICT vs. no ICT. Baseline characteristics were compared between the two groups; chi square test was used for categorical variables and t-test for continuous variables. The primary endpoint was overall survival compared between the two groups using Kaplan-Meier estimates. Cox regression was used for multivariate analysis. All analyses were conducted using SPSS version 19.0 statistical software.

Results:
Between July 2001 and July 2009, 97 patients with lower risk MDS and serum ferritin ≥ 1000 ng/ml were identified. Forty five (46.4%) received ICT and 52 did not. The ICT included deferasirox in 35 patients and deferoxamine in 10 patients. The baseline characteristics between the two groups (ICT and no ICT) are summarized in (table-1). No statistically significant difference in baseline characteristics was observed except more patients in the ICT group were transfusion dependent. The median duration of follow up was 85.7 month from time of diagnosis.
The median OS was 59 months (95%CI 22–48) for patients who received ICT compared to 33.7 months (95%CI 38–80) for patients who did not receive ICT (P= 0.013). After adjustment for age and cytogenetics in Cox multivariable analysis, ICT was associated with better OS (HR 0.52, 95%CI 0.31–0.87, P= 0.013). The rate of AML transformation was 21.2% in patients who did not receive ICT compared to 15.6% in those who had ICT. (p=0.33).

Conclusion:
ICT in lower risk MDS patients with elevated serum ferritin ≥ 1000 ng/ml was associated with improved overall survival and a trend to lower AML transformation. Results of ongoing randomized clinical study with deferasirox are needed to confirm the retrospective data.

Disclosures:
Komrokji: Novartis: Honoraria, Research Funding.
T Cells of Patients with Myelodysplastic Syndrome Are Frequently Derived From the Malignant Clone
Authors: Vercauteren Suzanne , Starczynowski Daniel T. , Sung Sandy , McNeil Kelly , Salski Chris , Jensen Clara-Lynn , Bruyere Helene , Lam Wan , Karsan Aly 
Published: October 2019

Abstract
Abstract 2808
T cell clonality is a common finding in myelodysplastic syndromes (MDS), but is believed to be a reactive phenomenon. We compared copy number abnormalities in matched CD34+ progenitor cells and CD3+ T cells from 40 MDS patients by array comparative genomic hybridization. In 9 of 14 patients with large copy number variants, we detected the same aberration in CD34+ and CD3+ cells. Chromosome 20q (2 patients), isodicentric × chromosome (2 patients), trisomy 8 (2 patients), 11q abnormalities (1 patient), deletion 5q (1 patient) and partial trisomy 9 with trisomies 19 and 22 (1 patient) were detected in the CD34+ and CD3+ cells of these patients. The presence of deletion 20q, trisomy 8 and deletion of chromosome arm 11q in the T cells of 3 patients was confirmed by FISH. Multiplex PCR for TCR γ rearrangement was performed on 6 of the 14 MDS patients with large copy number variants. T cell clonality was detected in 3 of 4 and oligoclonality in 1 of 4 patients when the copy number variant was present in both CD34+ and CD3+ cells. In contrast, the 2 cases lacking the CD34+ copy number variant in the CD3+ population were polyclonal at the TCR γ locus. These data suggest that in a large proportion of MDS at least a proportion of the T cells are part of the malignant clone, and that CD3+ cells do not represent an appropriate patient normal control for genome-wide studies.

Disclosures:
No relevant conflicts of interest to declare.
Intrinsic Resistance to JAK2 Inhibition in Myelofibrosis
Authors: Kalota Anna , Jeschke Grace R , Carroll Martin , Hexner Elizabeth 
Published: October 2019

Abstract
Abstract 2825
Myeloproliferative neoplasms (MPN) are a group of clonal hematopoietic stem cell disorders with a variable clinical course: essential thrombocytosis (ET) and polycythemia vera (PV) are associated with excess clotting and bleeding but an overall normal or near-normal life expectancy, while myelofibrosis has a variable but generally poor prognosis. The disorders are unified by the constitutive activation of the JAK2 pathway, most commonly by a point mutation in the pseudokinase domain of JAK2 (JAK2 V617F). Small molecule tyrosine kinase inhibitors have been shown to be active in both preclinical and late-phase clinical testing, and yet notably pharmacodynamic validation of target (JAK2) inhibition has never been rigorously demonstrated in clinical studies. Clinical investigation of JAK2 inhibitors has focused on myelofibrosis, with some unexpected results: while reduction in spleen size and amelioration of constitutional symptoms are frequent, only modest changes in mutant clonal burden have been observed and complete responses by any criteria are exceedingly rare. In order to develop a feasible and informative pharmacodynamic assay for measuring JAK2 signaling, we used phospho-specific flow cytometry on whole peripheral blood to measure phosphorylation of STAT3 and STAT5, the canonical targets of JAK2 in hematopoietic cells. Treating whole blood with tyrosine kinase inhibitors currently in clinical development, we observed a dose-dependent decrease in phospho-STAT5 and STAT3 in granulocytes treated ex vivo in cells from normal donors, patients with ET, PV and to a lesser extent from patients with myelofibrosis. We found that phosphorylation of STAT3 and STAT5 in cells from patients with myelofibrosis were significantly less inhibited than in PV and ET as well as normal donors. Using quantitative RT-PCR, we found that sensitivity to inhibition did not correlate with JAK2 V617F clonal burden. To determine whether extracellular determinants conferred resistance, mixing studies showed that plasma from patients with myelofibrosis did not transfer resistance. Plasma cytokines that signal through JAK2 and/or are known to be altered in myelofibrosis were measured and no single cytokine appeared to account for the observed pattern of resistance. Taken together these observations suggest that there are cell intrinsic mechanisms that define a priori resistance to JAK2 inhibition in myelofibrosis, and the lesion is localized upstream of STAT3 and STAT5.

Disclosures:
Carroll: Sanofi Aventis Corporation: Research Funding; TetraLogic Pharmaceuticals: Research Funding; Agios Pharmaceuticals: Research Funding; Glaxo Smith Kline, Inc.: Research Funding.
The Depth of Renal Response Strongly Predicts Overall Surival in Patients with AL Amyloidosis
Authors: Glavey Siobhan V , Dispenzieri Angela , Gertz Morie A , Kumar Shaji , Lacy Martha Q , Buadi Francis K , Rajkumar S. Vincent , Hayman Suzanne R , Lust John A , Russell Stephen J. , Zeldenrust Steven R , Dingli David , Hall Rob L , Leung Nelson 
Published: October 2019

Abstract
Abstract 2868

Introduction:
Improvement in renal parameters is fundamental for the assessment of organ response to treatment in immunoglobulin light chain amyloidosis (AL). Renal response, defined as a >50% reduction in proteinuria with <25% decrease in renal function, is associated with superior overall survival (OS); however, a systematic study of the interplay of proteinuria, creatinine, and free light chain has not been performed. The intent of this study is to better understand the components of the renal response criteria.

Methods:
Patients who underwent autologous stem cell transplantation from 1995 to 2010 were eligible for this retrospective analysis if they had > 1 year of follow-up and a baseline 24 hour urine protein > 1 g/d. Those who were dialysis dependent or died before 1 year were excluded as not evaluable for renal response.

Results:
Of the 435 patients screened, 152 met criteria. On univariate analysis, >50% proteinuria reduction (p < 0.001), serum free light chain (sFLC) reduction by >50% (p = 0.002), <25% increase in serum creatinine (Scr) (p = 0.0003), and a 50% proteinuria reduction within 15 months of treatment (p = 0.04) were associated with better OS. Multivariate analysis using a proportional hazard model showed that sFLC reduction by >50% (0.006), <25% increase in serum creatinine (Scr) (p = 0.0005) and >50% proteinuria reduction (p = 0.0006) were independently associated with OS. In addition, OS was significantly better among patients achieving >85% reduction in proteinuria than those with < 85% but >50%, p = 0.03 (Figure 1). Patients with >75% reduction in sFLC were more likely to achieve >50% proteinuria reduction (p = 0.009). Most importantly, among those with > 25% increase in Scr, only those patients who had <85% proteinuria reduction had a worse OS (Figure 2a, p = 0.006). There was no difference in OS among those with >85% proteinuria reduction and a rise in Scr of > 25% (Figure 2b, p = 0.77).

Conclusion:
Renal response is an excellent prognostic marker in patients with AL. This is the first study to show the depth of renal response correlates with OS. Patients who had the highest levels of proteinuria reduction (> 85%) had a significantly better OS than those with >50% but <85%. We also found that the negative impact of >25% decrease in renal function was only pertinent in those who did not have >85% reduction in proteinuria. These findings should help better refine the definition of renal response criteria in AL patients.

Disclosures:
Leung: Binding Site: Honoraria.
Autocrine Sonic Hedgehog Protects Multiple Myeloma Cells From Apoptosis and Enhances Drug Resistance
Authors: Liu Zhiqiang , Zheng Yuhuan , Li Haiyan , Lu Yong , Weber Donna M. , He Jin , Kwak Larry W , Yi Qing 
Published: October 2019

Abstract
Abstract 2904
The secreted protein sonic hedgehog (SHH) and the hedgehog signaling are of great importance in proliferation and differentiation of cells in the hematopoietic system, and also play a vital role in oncogenesis of B cell malignance. However, the functions and mechanism of SHH signaling in multiple myeloma (MM) is mostly unknown. Thus far, aberrant activation of the hedgehog signaling in tumor growth promoting and/or survival capabilities as well as a paracrine model of SHH secretion have been demonstrated in MM. In the current study, we demonstrated a new autocrine SHH functioning manner in MM cells. The Shh mRNA and the SHH protein were highly expressed both in the MM cell lines and in purified CD138+ MM cells from patients using real-time PCR, Western Blot and immunohistochemistry analyses, respectively; and the SHH protein was also detected in the culture medium. Accordingly, the Hh ligand receptor PTCH1 and PTCH2 as well as the transcriptional factor GLI1 were all overexpressed in MM cells, indicating the activation of Hh signaling pathway. Autocrine SHH played a role in MM cells survival and protected MM cells from apoptosis in vitro, and autocrine SHH accelerated xenograft tumor growth in myeloma-SCID mouse model in vivo. Moreover, autocrine SHH enhanced drug resistance of MM cells, as SHH overexpressed CAG cells (SHH+CAG) had a significantly low apoptosis rate when treated with chemotherapy drugs dexamethasone or bortezomib, as compared with wild type cells (wt-CAG). On the contrary, SHH knockdown cells (SHH-CAG) had a dramatically higher apoptosis rate. Blocking autocrine SHH ligand and treating cells with dexamethasone or bortezomib significantly improved the drug killing effect. Finally, we found that upregulated BLC2 via SHH-Gli1signaling is the signaling pathway by which MM cells enhanced the drug resistance. Our study provides a new insight into the biologic function of the autocrine SHH in proliferation, survival and the drug resistance in the myeloma cells.

Disclosures:
No relevant conflicts of interest to declare.
Upregulation of CD274 facilitates ex Vivo Expanded Hematopoietic Stem Cells Overcome the MHC Barrier in Allogeneic Transplantation
Authors: Zhang Chengcheng 
Published: October 2019

Abstract 2965
Success of allogeneic transplantation is severely hampered by low levels of donor engraftment and high risks of graft-versus-host disease (GVHD). Transplantation of purified allogeneic blood stem cells (HSCs) diminishes the risk of GVHD, but also results in decreased engraftment. Here we show that ex vivo expanded HSCs efficiently overcame the major histocompatibility complex (MHC) barrier and engrafted allogeneic recipient mice. As measured by limiting dilution analysis, there was a 40-fold increase in the allograft ability of the 8-day-cultured HSCs compared to that of the freshly isolated HSCs. We found that both increased numbers of HSCs and cultured-induced elevation of expression of the immune inhibitor on the surface of HSCs contributed to the enhancement. CD274, an immune inhibitor that is expressed on freshly isolated HSCs, was significantly upregulated on cultured HSCs. The use of CD274-deficient HSCs or HSCs treated with a CD274 neutralizing antibody abrogated the ability of cultured but unexpanded HSCs to cross the MHC barrier. To test whether cultured HSCs can be used to cure genetic diseases in allogeneic recipients, we used ex vivo expanded allogeneic HSCs for transplantation and successfully rescued the lethal phenotype of DNA-PK knock-in mice. Our study suggests that HSCs can be manipulated to regulate their immune privilege and this will likely lead to development of new strategies for successful allogeneic transplantation for human patients.

Disclosures:
No relevant conflicts of interest to declare.
90yttrium Ibritumomab Tiuxetan-BEAM Followed by Autologous Stem Cell Transplantation Significantly Improves Overall Survival After Rituximab Containing Induction Therapy in Patients with High-Risk Aggressive B Cell Non-Hodgkin's Lymphoma
Authors: Wondergem Marielle , de Rooij Madelon , Zijlstra Josee , Visser Otto J , Ossenkoppele Gert , Huijgens Peter C. 
Published: October 2019

Abstract
Abstract 3078

Introduction
Adding rituximab to induction therapy has improved overall survival in patients with relapsed or refractory diffuse large B cell lymphoma (DLBCL) after high dose chemotherapy followed by autologous stem cell transplantation (AuSCT) to 50–60%. However, there is still room for improvement. Addition of 90Yttrium ibritumomab tiuxetan prior to the BEAM conditioning regimen seems feasible and results in promising data with respect to disease free and overall survival in high risk DLBCL patients even when treated with rituximab containing induction therapy. At the VU University Medical center, rituximab was added to (re-)induction therapy starting July 2001. From 2006 we started to add 90Yttrium ibritumomab tiuxetan (Zevalin®) to BEAM (Z-BEAM) in high risk DLBCL patients. In this retrospective analysis we compare outcome of Z-BEAM versus BEAM, both followed by AuSCT.

Patients and methods
All high risk DLBCL patients consolidated with high dose (radio-immuno) chemotherapy and AuSCT in CR or PR after rituximab-containing induction therapy were included. High-risk DLBCL was defined as either relapsed or refractory DLBCL or as histological transformation of indolent NHL. AuSCT was preceded by BEAM conditioning and 90Yttrium ibritumomab tiuxetan (0, 4 mCi/kg, max 32 mCi, starting 2006: Z-BEAM group) or by BEAM only (BEAM group). EFS and OS were estimated using the Kaplan-Meier method and compared using the log rank test.

Results
43 patients received Z-BEAM and 42 patients received BEAM conditioning. Median age was 56 and 52 years respectively. No significant differences in disease characteristics were seen. Median follow up (range) was 15 months (6–54) and 39 months (0–112) respectively. Overall survival was significantly better in the Z-BEAM group compared with the BEAM group (p=0.02) with an estimated 2 year overall survival of 90% vs. 65%. (fig 1.) In the first 2 years of follow up 7 patients in the Z-BEAM group relapsed compared to 11 in the BEAM group, this did not reach significance (p=0.09). Median time to recovery of neutrophils and thrombocytes was not significantly different. Moreover, there was no significant difference in TRM (no TRM in the Z-BEAM group versus 2 patients in the BEAM group). Patients who relapsed, in both groups, were able to receive re-induction chemotherapy and, if indicated, allogeneic SCT without being compromised by decreased bone marrow reserve or non haematological toxicities.

Conclusion
Adding 90Yttrium ibritumomab tiuxetan to the BEAM conditioning regimen preceding AuSCT leads to a significant improvement in overall survival in high risk DLBCL patients, even if they have received rituximab during (re)induction.

Disclosures:
No relevant conflicts of interest to declare.
Relapse of POEMS Following Autologous Stem Cell Transplantation: A Single Center Experience
Authors: D'Souza Anita , Buadi Francis K , Lacy Martha Q , Gertz Morie A , Hayman Suzanne R , Kumar Shaji , Dingli David , Zeldenrust Steven R , Dispenzieri Angela 
Published: October 2019

Abstract
Abstract 3101
The POEMS (polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes) syndrome is a rare paraneoplastic disorder secondary to a clonal plasma cell process. The most experience with successful outcomes in POEMS with disseminated disease has been with high dose chemotherapy followed by autologous stem cell transplantation (ASCT). However, the risk of relapse of POEMS following an ASCT or the outcome of the patients who relapse is not known. We therefore performed a retrospective review of POEMS patients who underwent ASCT at our center and subsequently relapsed or progressed.
Over the past 12 years, 58 patients with POEMS underwent autologous stem cell transplantation at the Mayo Clinic, Rochester between Mar 18, 1999 and Jun 22, 2011. With a median follow up of 40 months (1–147 months), 12 patients have relapsed. The median time to relapse was 41 months. The 1, 2, and 5 year PFS rates were 98%, 94%, and 75%, respectively (Figure 1), and the 1, 2, and 5 year OS rates were 98%, 98%, and 94%.
Of the 12 patients with documented relapse, 7 had baseline PET/CT scans all of which had FDG avid lesions. By 1 year, the FDG avidity had not resolved in 4 of these patients who then went on to either develop additional lesions or increasing SUV of existing lesions. Of the 12 patients with documented relapse, 8 had baseline VEGF measurements, and all but 1 had normalization by 1 year. The first sign of relapse was a clinical deterioration in 2, a rising M-protein in 3, and a rising plasma VEGF level in 5 patients. All of these patients had new or worsening of existing lesions on PET/CT scan (n= 9) or x-ray imaging (n= 3). The symptoms of clinical relapse included pain at the site of the lytic lesion and generalized pain with swelling. Of the patients who relapsed, 5 were treated with radiation therapy, 4 received lenalidomide or thalidomide, 2 had alkylator based therapy and 1 had bortezomib based therapy. One patient was treated with surgical resection of his hepatic plasmacytoma and 2 patients have been observed without needing definitive treatment as of yet. One patient also received anti-VEGF treatment with bevacizumab unsuccessfully after failing cyclophosphamide therapy.
In this large cohort of POEMS patients treated with high dose chemotherapy and autologous stem cell transplantation in a single center, a relapse rate of 21% was noted. Not every patient who relapsed has been deemed to need further treatment, and most patients could be salvaged with chemotherapy or radiation. Only one patient died from relapsed POEMS following stem cell transplantation.

Disclosures:
No relevant conflicts of interest to declare.