Frequency of heterozygous TET2 deletions in myeloproliferative neoplasms

The Philadelphia chromosome (Ph)-negative myeloproliferative neoplasms (MPNs), including polycythemia vera, essential thrombocythemia, and primary myelofibrosis, are a group of clonal hematopoietic stem cell disorders with overlapping clinical and cytogenetic features and a variable tendency to evolve into acute leukemia. These diseases not only share overlapping chromosomal abnormalities but also a number of acquired somatic mutations. Recently, mutations in a putative tumor suppressor gene, ten-eleven translocation 2 (TET2) on chromosome 4q24 have been identified in 12% of patients with MPN. Additionally 4q24 chromosomal rearrangements in MPN, including TET2 deletions, have also been observed using conventional cytogenetics. The goal of this study was to investigate the frequency of genomic TET2 rearrangements in MPN using fluorescence in situ hybridization as a more sensitive method for screening and identifying genomic deletions. Among 146 MPN patients, we identified two patients (1.4%) who showed a common 4q24 deletion, including TET2. Our observations also indicated that the frequency of TET2 deletion is increased in patients with an abnormal karyotype (5%)

A Multidisciplinary Investigation of a Polycythemia Vera Cancer Cluster of Unknown Origin

Cancer cluster investigations rarely receive significant public health resource allocations due to numerous inherent challenges and the limited success of past efforts. In 2008, a cluster of polycythemia vera, a rare blood cancer with unknown etiology, was identified in northeast Pennsylvania. A multidisciplinary group of federal and state agencies, academic institutions, and local healthcare providers subsequently developed a multifaceted research portfolio designed to better understand the cause of the cluster. This research agenda represents a unique and important opportunity to demonstrate that cancer cluster investigations can produce desirable public health and scientific outcomes when necessary resources are available

Familial Haploidentical Stem Cell Transplant in Children and Adolescents With High-Risk Sickle Cell Disease: A Phase 2 Clinical Trial

Sickle cell disease (SCD) is an autosomal recessive disorder associated with cerebral vasculopathy, stroke, acute chest syndrome, pulmonary hypertension and/or frequent vaso-occlusive crises, and a high risk of early mortality.1,2 Studies have reported 90% to 100% event-free survival (EFS) following human leukocyte antigen matched sibling allogeneic stem cell transplant.3,4 Reported results have used unrelated allogeneic donor sources; however, a paucity of unrelated matched donors and a higher than expected rate of graft failure and chronic graft-vs-host disease (GVHD) were notable disadvantages.5 The CD34+ enrichment and mononuclear cell (MNC) addback (2 × 105 CD3 cells/kg of recipient body weight) have been reported following matched unrelated donor transplant that resulted in 100% engraftment and a low cumulative incidence of acute GVHD and chronic GVHD.

Seasonal challenges of tropical bats in temperate zones

To examine the challenges faced by free-ranging Rousettus aegyptiacus living at the northern edge of their distribution, we performed a retrospective analysis of 2196 clinical cases reported by a bat rescue NGO over a period of 36 months, from throughout Israel. All cases of injured bats were evaluated and categorized according to date, place, sex, age, and etiology of the morbidity. The data analysis revealed an increase in all types of morbidity during the wintertime, with more than two-fold the number of cases per week compared to in the summer, over three consecutive years. Moreover, we found that the number of abandoned pups peaked during spring and summer, when adult morbidity is minimal. We characterized two prominent types of previously undescribed morbidities in R. aegyptiacus. We also employed GPS tracking to monitor the movement and foraging of dozens of bats, and to examine the potential correlates of elevated winter morbidity. Our results suggest that it is mainly harsh weather that drives the observed winter morbidity, with food limitations playing a minor-role. We hypothesize that R. aegyptiacus, of tropical origin, is facing major seasonal survival difficulties near the northern edge of its distribution, probably limiting its spread further northwards still

Analysis of the Global Methylation Profile of Accelerated and Blast Phase Myeloproliferative Neoplasms and Its Association with Response to Decitabine-Based Therapy

Methylation profiling in myeloid malignancies such as Acute Myeloid Leukemia (AML) and Chronic Myelomonocytic Leukemia (CMML) has demonstrated the ability to define distinct biological and clinical subgroups, including predicting which patients will respond to therapy with a hypomethylating agent (HMA). The Philadelphia-chromosome negative myeloproliferative neoplasms (MPNs) carry an inherent risk of progression to an accelerated-phase disease (AP; 10-19% blasts in the peripheral blood or bone marrow), as well as to blast phase disease (BP; ≥ 20% blasts in the peripheral blood or bone marrow), which is associated with a poor prognosis. It is unknown whether the methylation profiles of MPN-AP/BP cases may further help identify distinct biological, genomic, and clinical subgroups, including identifying patients more likely to respond to HMA. We recently carried out a phase I/II study to test the safety and efficacy of combination therapy with the JAK1/2 inhibitor ruxolitinib (RUX) and the HMA Decitabine (DAC) in patients with MPN-AP/BP (MPD-RC 109 study; NCT02076191). A total of 46 patients were accrued to the phase I and II studies. 37 patients were evaluable for response. Complete response (CR) occurred in 10%, Complete Response with incomplete count recovery (CRi) in 24%, Partial Response in 24%. 42% of patients had no response to therapy. Using samples available from the MPD-RC 109 study, we sought to assess whether the baseline global methylation profile predicts for response to this regimen. Further, we sought to utilize this dataset to determine if IDH2 mutations (amongst the most common mutations in MPN-AP/BP) are associated with a distinct methylation profile, as has been demonstrated in de novo AML. We carried out a pilot study of 11 MPN-AP/BP patients from the MPD-109 phase I/II trial and performed Enhanced Reduced Representation Bisulfite Sequencing (ERRBS) for DNA methylation quantification at ~3M CpG sites across the genome. Baseline DNA methylation profiles were compared between Responder (R) and Non-responder (NR) patients. Notably, unsupervised analysis using correspondence analysis (COA) demonstrated an almost complete separation of the two groups of patients (Fig 1A), while supervised analysis using a beta binomial model identified 134 differentially methylated regions (DMRs) (FDR25%) between the two groups at diagnosis (Fig 1B). Similar to our prior observation in CMML, response-associated DMRs were depleted from promoter regions (p<0.001) and enriched at enhancers (p<0.001), and were annotated to genes in pathways related to myeloid biology and metabolic processes (Fig 1C). We next carried out a pilot study to characterize the epigenetic abnormalities of IDH2-mutant MPN-AP/BP cases. For this purpose, we compared the genome-wide DNA methylation profiles of 12 IDH2-mutant to 7 IDH1/2 wild type MPN-AP/BP cases using ERRBS. Unsupervised analysis based on the DNA methylation profiles alone showed a strong trend to naturally segregate mutant from wild-type cases, indicating strong underlying epigenetic differences (Fig.1D). A supervised analysis using the beta binomial method identified 1,477 differentially methylated regions (DMRs) between the two groups (average absolute methylation difference ≥25% and FDR <10%) (Fig 1E). Eighty percent of these DMRs corresponded to sites that were hypermethylated in IDH2-mutant cases compared to wild type. These DMRs were strongly enriched in CpG shores and enhancer regions (p value < 0.001 for both) (Fig 1F). Our data demonstrate that the methylation profile of MPN-AP/BP may predict for response to HMA-based therapy. Such data could be used to guide therapeutic decisions and select patient for whom HMA has the highest likelihood of procuring a response. As well, these findings indicate that IDH2-mutant MPN-AP/BP are epigenetically distinct, and given the preferred targeting of regulatory elements, these epigenetic differences may play a functional role in disease biology. Further validation of these observations is required. Updated data, including analysis of further cases, and RNA-sequencing analysis of gene-expression and pathway enrichment of genes differentially methylated between responders and non-responders, and IDH2 mutated and wildtype cases will be presented at the conference. Disclosures Rampal: Constellation: Research Funding; Pharmaessentia: Consultancy; CTI Biopharma: Consultancy; Promedior: Consultancy; Celgene: Consultancy; Incyte: Consultancy, Research Funding; Abbvie: Consultancy; Galecto: Consultancy; Jazz Pharmaceuticals: Consultancy; Blueprint: Consultancy; Stemline: Consultancy, Research Funding. Mascarenhas:Celgene, Prelude, Galecto, Promedior, Geron, Constellation, and Incyte: Consultancy; Incyte, Kartos, Roche, Promedior, Merck, Merus, Arog, CTI Biopharma, Janssen, and PharmaEssentia: Other: Research funding (institution). Levine:Morphosys: Consultancy; Prelude Therapeutics: Research Funding; Novartis: Consultancy; Amgen: Honoraria; Lilly: Consultancy, Honoraria; Janssen: Consultancy; Astellas: Consultancy; Roche: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Imago: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Isoplexis: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Loxo: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Qiagen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria. Hoffman:Novartis: Membership on an entity's Board of Directors or advisory committees; Protagonist: Consultancy; Forbius: Consultancy; Dompe: Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees