Faculty Bibliography

Mutations in genes encoding epigenetic regulators are commonly observed at relapse in B cell acute lymphoblastic leukemia (B-ALL). Loss-of-function mutations in SETD2, an H3K36 methyltransferase, have been observed in B-ALL and other cancers. Previous studies on mutated SETD2 in solid tumors and acute myelogenous leukemia support a role in promoting resistance to DNA damaging agents. We did not observe chemoresistance, an impaired DNA damage response, nor increased mutation frequency in response to thiopurines using CRISPR-mediated knockout in wild-type B-ALL cell lines. Likewise, restoration of SETD2 in cell lines with hemizygous mutations did not increase sensitivity. SETD2 mutations affected the chromatin landscape and transcriptional output that was unique to each cell line. Collectively our data does not support a role for SETD2 mutations in driving clonal evolution and relapse in B-ALL, which is consistent with the lack of enrichment of SETD2 mutations at relapse in most studies.

BACKGROUND:A recent survey of pediatric hematology oncology (PHO) physicians identified that a majority believe fellows are struggling to find jobs that align with their goals. Career development for trainees has historically been home institution-specific, limiting fellows' exposures to career path possibilities. The "virtual-Symposium of Pediatric Hematology/Oncology of New York (v-SYMPHONY)" instituted a tristate Career Development Series for PHO trainees to better address their needs and increase awareness of the variety of PHO career opportunities. PROCEDURE/METHODS:The v-SYMPHONY Career Development Series incorporated three sessions: (a) institutional perspective, (b) individual perspectives, and (c) nuts and bolts of job search. Pre- and post-series surveys were administered to participants to measure impact. RESULTS:Forty-one fellows registered for the series and completed a pre-survey. Over half (54%) were in their third or later year of fellowship. Careers with a clinical focus were the most commonly desired career path (59%). Most had received career development advice only from faculty within their institutions (90%). Post-surveys were completed by 11 PHO fellows. Overall, 100% of respondents reported benefiting from the career sessions and recommended the series should be repeated annually. Over 90% learned new information to prepare for the job search. CONCLUSIONS:The v-SYMPHONY Career Development Series for PHO fellows across multiple institutions was established and was extremely well received by its participants. PHO fellows agreed that these sessions were beneficial in helping prepare them for the job search process. An annual regional Career Development Series is feasible and is strongly suggested to support PHO fellows.

Acute myeloid leukemia (AML) is a hematopoietic malignancy with poor prognosis and limited treatment options. Here we provide a comprehensive census of the bone marrow immune microenvironment in adult and pediatric patients with AML. We characterize unique inflammation signatures in a subset of AML patients, associated with inferior outcomes. We identify atypical B cells, a dysfunctional B-cell subtype enriched in patients with high-inflammation AML, as well as an increase in CD8⁺GZMK⁺ and regulatory T cells, accompanied by a reduction in T-cell clonal expansion. We derive an inflammation-associated gene score (iScore) that associates with poor survival outcomes in patients with AML. Addition of the iScore refines current risk stratifications for patients with AML and may enable identification of patients in need of more aggressive treatment. This work provides a framework for classifying patients with AML based on their immune microenvironment and a rationale for consideration of the inflammatory state in clinical settings.

PURPOSE/OBJECTIVE:Diagnosis of Mismatch Repair Deficiency (MMRD) is crucial for tumor management and early detection in patients with the cancer predisposition syndrome constitutional mismatch repair deficiency (CMMRD). Current diagnostic tools are cumbersome and inconsistent both in childhood cancers and in determining germline MMRD. PATIENTS AND METHODS/METHODS:We developed and analyzed a functional Low-pass Genomic Instability Characterization (LOGIC) assay to detect MMRD. The diagnostic performance of LOGIC was compared with that of current established assays including tumor mutational burden, immunohistochemistry, and the microsatellite instability panel. LOGIC was then applied to various normal tissues of patients with CMMRD with comprehensive clinical data including age of cancer presentation. RESULTS:). CONCLUSION/CONCLUSIONS:LOGIC was a robust tool for the diagnosis of MMRD in multiple cancer types and in normal tissues. LOGIC may inform therapeutic cancer decisions, provide rapid diagnosis of germline MMRD, and support tailored surveillance for individuals with CMMRD.

PURPOSE/OBJECTIVE:Constitutional mismatch repair deficiency syndrome (CMMRD) is a lethal cancer predisposition syndrome characterized by early-onset synchronous and metachronous multiorgan tumors. We designed a surveillance protocol for early tumor detection in these individuals. PATIENTS AND METHODS/METHODS:Data were collected from patients with confirmed CMMRD who were registered in the International Replication Repair Deficiency Consortium. Tumor spectrum, efficacy of the surveillance protocol, and malignant transformation of low-grade lesions were examined for the entire cohort. Survival outcomes were analyzed for patients followed prospectively from the time of surveillance implementation. RESULTS:< .0001). Of the 64 low-grade tumors detected, the cumulative likelihood of transformation from low-to high-grade was 81% for GI cancers within 8 years and 100% for gliomas in 6 years. CONCLUSION/CONCLUSIONS:Surveillance and early cancer detection are associated with improved OS for individuals with CMMRD.

Background/UNASSIGNED:Effective therapies to combat coronavirus 2019 (COVID-19) are urgently needed. Hydroxychloroquine (HCQ) has in vitro antiviral activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but the clinical benefit of HCQ in treating COVID-19 is unclear. Randomized controlled trials are needed to determine the safety and efficacy of HCQ for the treatment of hospitalized patients with COVID-19. Methods/UNASSIGNED:We conducted a multicenter, double-blind randomized clinical trial of HCQ among patients hospitalized with laboratory-confirmed COVID-19. Subjects were randomized in a 1:1 ratio to HCQ or placebo for 5 days and followed for 30 days. The primary efficacy outcome was a severe disease progression composite end point (death, intensive care unit admission, mechanical ventilation, extracorporeal membrane oxygenation, and/or vasopressor use) at day 14. Results/UNASSIGNED: = .350). There were no significant differences in COVID-19 clinical scores, number of oxygen-free days, SARS-CoV-2 clearance, or adverse events between HCQ and placebo. HCQ was associated with a slight increase in mean corrected QT interval, an increased D-dimer, and a trend toward an increased length of stay. Conclusions/UNASSIGNED:In hospitalized patients with COVID-19, our data suggest that HCQ does not prevent severe outcomes or improve clinical scores. However, our conclusions are limited by a relatively small sample size, and larger randomized controlled trials or pooled analyses are needed.

A subset of B cell acute lymphoblastic leukemia (B-ALL) patients will relapse and succumb to therapy-resistant disease. The bone marrow microenvironment may support B-ALL progression and treatment evasion. Utilizing single-cell approaches, we demonstrate B-ALL bone marrow immune microenvironment remodeling upon disease initiation and subsequent re-emergence during conventional chemotherapy. We uncover a role for non-classical monocytes in B-ALL survival, and demonstrate monocyte abundance at B-ALL diagnosis is predictive of pediatric and adult B-ALL patient survival. We show that human B-ALL blasts alter a vascularized microenvironment promoting monocytic differentiation, while depleting leukemia-associated monocytes in B-ALL animal models prolongs disease remission in vivo. Our profiling of the B-ALL immune microenvironment identifies extrinsic regulators of B-ALL survival supporting new immune-based therapeutic approaches for high-risk B-ALL treatment.

Background: Outcomes for children with relapsed B-ALL remain poor, in part due to genetic and epigenetic lesions that confer drug resistance to one or more classes of agents used in therapy. SETD2, an epigenetic modifier, commonly harbors loss of function mutations in relapsed pediatric B-ALL. Prior studies have demonstrated the tumor suppressor function of SETD2 in an AML model as well as its role in resistance to DNA damaging agents, but the role of SETD2 mutations in relapsed B-ALL is not yet understood.
Objective(s): Determine the role of relapse-specific SETD2 loss-offunction mutations in disease progression by measuring proliferation and drug sensitivity in isogenic B-ALL cell lines that recapitulate these mutations. Design/Method: A panel of isogenic B-ALL cell lines (697 and KOPN-8) were generated with knockout of SETD2 using the CRISPR/Cas9 system. Conversely, B-ALL cell lines already harboring SETD2 heterozygous mutations (REH and RCH) had SETD2 expression restored using an inducible vector system. Western blot analysis was used to confirm the relative expression of SETD2 and downstream markers of DNA damage response in engineered cell lines. Isogenic cell lines were plated with or without HEK 293 stromal cells and then exposed to vincristine, etoposide, cytarabine, prednisone, or mercaptopurine for 72 hours. Cell viability of cells plated without stroma was measured using CellTiter-Glo. Apoptosis of cells plated with stroma was measured using flow cytometric analysis of apoptosis markers Annexin V and 7AAD. Relative proliferation of all untreated cell lines were measured over 168 hours using an automated cell counter.
Result(s): 697 and KOPN-8 clones with either a SETD2 heterozygous mutation or compound heterozygous mutations exhibited similar rates of proliferation compared to their respective isogenic controls. The half-maximal inhibitory concentrations (IC50) of all chemotherapy agents were similar in mutant clones and their isogenic controls, regardless of the presence of stromal cells. REH and RCH with reexpression of SETD2 also had similar rates of proliferation and IC50 compared to their isogenic controls. No increase in DNA damage was observed upon knockout of SETD2.
Conclusion(s): Loss of SETD2 expression in B-ALL cell lines does not confer increased resistance to conventional chemotherapy agents, either in isolation orwhen grown in a stromal microenvironment. Conversely, re-expression of SETD2 in lines that already harbored SETD2 mutations does not restore chemosensitivity. We postulate that SETD2 deletions alone may not confer a clonal advantage, but may operate in collaboration with other genetic alterations in a cell context-specific manner