Translocation Partner Research Articles

Population-Wide Introduction of Dose-Adjusted EPOCH-R Is Associated with Improved Outcome of High Grade B-Cell Lymphoma with MYC and BCL2 Rearrangements with Diffuse Large B-Cell Lymphoma Morphology

Population-Wide Introduction of Dose-Adjusted EPOCH-R Is Associated with Improved Outcome of High Grade B-Cell Lymphoma with MYC and BCL2 Rearrangements with Diffuse Large B-Cell Lymphoma Morphology

Crebbp Alterations Are Associated with a Poor Prognosis in De Novo AML

Introduction: The translocation, t(8;16)(p11;p13), results in the fusion between KAT6A and CREBBP and has been associated with a poor prognosis in both pediatric and adult acute myeloid leukemia (AML). This lesion has therefore been re-classified as high risk on the active Phase 3 Children's Oncology Group (COG) trial for de novo AML, AAML1831 (NCT04293562). Less is known about the prognostic significance of CREBBP sequence variants.Methods: CREBBP variant status was determined in patients with AML enrolled on 4 successive COG trials for de novo pediatric AML (NCT00003790, NCT00070174, NCT01407757, NCT01371981). Fusions involving CREBBP were prospectively obtained via conventional cytogenetics and retrospectively confirmed via RNAseq. Insertions and deletions (indels) leading to frameshift mutations and single nucleotide variants (SNVs) were retrospectively interrogated via next generation sequencing.Results: Of 2216 patients (age: 0-29.8 years), 55 (2.5%) patients had an alteration involving CREBBP. Sixteen (29%) of these were a fusion involving CREBBP (CREBBP/fus), with KAT6A being the most common translocation partner (n=15) and the remaining translocation involving ANK1. The remaining 39 patients (71%) had a CREBBP mutation (CREBBP/mut), including 19 with an indel (CREBBP/indel) leading to a frameshift mutation and 20 with a SNV (CREBBP/SNV).We compared clinical and biologic characteristics between the three cohorts. CREBBP/fus patients were significantly younger than CREBBP/indel and CREBBP/SNV patients (median ages of 2.6 vs. 7.8 vs. 11.9 years; p=0.027). There was a higher prevalence of t(8;21)/RUNX1-RUNX1T1 in CREBBP/indel patients compared to CREBBP/SNV patients (42.1% vs. 5%; p=0.008). In contrast, CREBBP/SNV patients were more likely to be associated with a normal karyotype (40% vs. 5.3%; p=0.02). There was a similar prevalence of co-occurring high-risk lesions in CREBBP/indel (n=5; CBFA2T3-GLIS2, KMT2A-AFF1, KMT2A-MLLT4, MLLT10-PICALM, NUP98-HOXA9) and CREBBP/SNV (n=7; DEK-NUP214, ETV6-FOXO1, FUS-ERG, NUP98-NSD1, ETV6-MNX1, FLT3-ITDx2) patients. There was otherwise no difference between presenting WBC count, FLT3-ITD, NPM1, CEBPA, remission rates or MRD status after Induction 1 therapy.Patients with any CREBBP alteration had a significantly worse 5-year event free survival (EFS) compared to patients without (25.9% vs. 45.2%; p=0.002) and this inferior EFS overlaps with contemporarily defined high-risk patients (Figure 1a). Evaluation of outcomes based on type of alteration demonstrated a similar 5-year EFS of 33.3% and 23.1% between CREBBP/fus and CREBBP/mut patients, respectively (Figure 1b; p=0.832). This poor EFS was maintained in the CREBBP/indel patients with a co-occurring t(8;21) (n=8, 5-year EFS 12.5%). When patients with co-occurring high-risk lesions were excluded from analysis, the remaining CREBBP/mut (n=27) patients maintained their poor EFS (29.6%). Despite their poor EFS, CREBBP/mut patients had an analogous overall survival (OS) to non-CREBBP patients (57.4% vs. 62.3%; p=0.499, Figure 1c), demonstrating that these patients could be successfully salvaged following relapse. In contrast, all patients with CREBBP/fus that relapsed subsequently died from their disease (OS 33.3%).Conclusions: In a large study of CREBBP alterations in pediatric patients with de novo AML, we show that these patients have a dismal EFS, regardless of alteration type. Further, despite enrichment of t(8;21), the favorable prognosis typically conferred by this alteration was abrogated by the co-occurrence of CREBBP/indel. Similarly, by excluding patients with co-occurring high-risk lesions from analysis, we show that these poor outcomes persist in a cohort of patients that would otherwise be considered low risk. Translocations between CREBBP and KAT6A in patients over 90 days of age are considered high risk on the active COG phase 3 trial. Given the inferior EFS and high salvage rates associated with other CREBBP alterations, intensification of upfront treatment, including hematopoietic stem cell transplant, should be considered in this population.The authors would like to acknowledge Astellas Pharma Global Development, Inc. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

An Open-Source Toolkit That Powers the Genome-Wide Analysis of Mature B-Cell Lymphomas (GAMBL) Project

Introduction: Genome- and transcriptome-wide analyses continue to enhance our understanding of the molecular pathogenesis of cancer. In lymphomas, this has enabled the identification of hundreds of recurrently mutated genes, highlighting genetic heterogeneity and relationships both within and among clinical entities. While the growing availability of lymphoma genomic data sets can be leveraged to integrate genomic analyses into diagnostic testing and clinical trials, the ability to rapidly process genomic data sets in a reproducible manner serves as a barrier to this goal. To this end, we developed a suite of tools Lymphoid Cancer Research modules (LCR-modules) to facilitate the discovery of novel drivers and molecular features in lymphoma cancers and perform quantitative comparisons between disease entities. We demonstrate here how this toolkit enabled a meta-analysis of lymphoma genomic data involving genome-wide profiles of 3330 patients.Methods: We assembled a collection of whole genome, whole exome, and RNA sequencing data from a combination of controlled-access repositories and ongoing projects at BC Cancer. The scope of genomic analysis of mature B-cell lymphomas (GAMBL) project includes cell lines and patient tumors from all common mature B cell neoplasms, comprising a total of 4612 samples from 3330 patients. To facilitate the project, we developed a suite of open-source and custom bioinformatics tools (https://github.com/LCR-BCCRC/lcr-modules) that leverages the Snakemake workflow management system and includes lymphoma-centric modules for the discovery and annotation of common mutation types, analysis of B-cell receptor repertoires and discovery of novel aSHM targets and relevant non-coding mutations, and RNA-seq analysis with batch correction and normalization. Individual modules are configured to create an automated, scalable, and reproducible workflow that runs each step as dictated by the availability of new data. The cohort-level integrative analysis and comparisons across entities are handled by our custom R package GAMBLR, which facilitates open-ended data analysis and custom visualizations.Results: Simple somatic mutations (SSM) were detected using a workflow that utilizes four algorithms to identify high-confidence variants with validated default thresholds for filtering of germline variants and common FFPE-associated artifacts, allowing for processing of samples without matched normal tissue. This automated and reproducible workflow facilitated the discovery of novel genes significantly mutated across lymphomas and broadened our understanding of the scope of aberrant somatic hypermutation (aSHM) and other non-coding mutations. Specifically, HNRNPU, STAT3, TFAP4, RRAGC were found to be mutated at relatively low frequencies, and their presence is a distinct feature of certain lymphomas or novel genetic subgroups within lymphoma types (Figure 1A).The aSHM analysis and discovery of novel hypermutated regions is handled by a custom tool Rainstorm. As a result, we were able to detect sites preferentially hypermutated in a single entity, such as the transcription start site of BACH2, mutated at lower rates than the other common target sites but significantly more in BL compared to other entities (Figure 1B). Combining aSHM at target sites discovered using our toolkit with other genetic features allowed us to explore and establish novel genetic subgroups within Burkitt lymphoma and follicular lymphoma.SV analysis can be conducted using Manta, GRIDSS, and JaBbA modules with downstream processing in GAMBLR. In B-cell lymphomas, the most common SVs identified using the automated workflow were targeting MYC, BCL2, and CCND1. Unsurprisingly, the most common translocation partner among B-cell lymphomas was the immunoglobulin heavy chain, but the novel BCL6-FOXP1, CD274-BACH2, BCL6-RHOH translocations in DLBCLs and MYC-BCL6 translocations in BLs were identified, among others (Figure 1C).Conclusions: We present here the modularized workflow for scalable and automated analysis of genomic and transcriptomic data and demonstrate that it can be successfully deployed across thousands of tumour samples for the discovery of known and novel lymphoma biology. This represents an important advancement in reproducibility that will facilitate clinical translation of genomic discoveries. [Display omitted] DisclosuresGrande: Sage Bionetworks: Current Employment. Coyle: Allakos, Inc.: Consultancy. Steidl: AbbVie: Consultancy; Trillium Therapeutics: Research Funding; Epizyme: Research Funding; Seattle Genetics: Consultancy; Curis Inc.: Consultancy; Bayer: Consultancy; Bristol-Myers Squibb: Research Funding. Scott: Abbvie: Consultancy; NanoString Technologies: Patents & Royalties: Patent describing measuring the proliferation signature in MCL using gene expression profiling.; Celgene: Consultancy; AstraZeneca: Consultancy; Incyte: Consultancy; Janssen: Consultancy, Research Funding; Rich/Genentech: Research Funding; BC Cancer: Patents & Royalties: Patent describing assigning DLBCL COO by gene expression profiling–licensed to NanoString Technologies. Patent describing measuring the proliferation signature in MCL using gene expression profiling. . Morin: Epizyme: Patents & Royalties; Celgene: Consultancy; Foundation for Burkitt Lymphoma Research: Membership on an entity's Board of Directors or advisory committees.

Targeted Next Generation Sequencing Reveals a Third Breakpoint Cluster Region and New Partner Genes in the KMT2A Recombinome

Chromosomal rearrangements of the KMT2A gene are associated with acute leukemias and myelodysplastic syndromes. The large number of known KMT2A fusions (>100) renders a precise diagnosis a demanding task. More than 50% of all KMT2A partner genes have been analyzed at the DCAL, including the novel partner genes BCAS4, FAM13A, RANBP3, and STK4. Even though all KMT2A rearrangements are associated with high-risk acute leukemia, the outcome (poor or very poor) is influenced by the partner gene. So far, we have analyzed more than 3,200 patients positive for a KMT2A rearrangement. The breakpoints of these cases are located mainly in the major breakpoint cluster region (bcr1) and to a small extent in the recently described minor bcr (bcr2). A small number of breakpoints were also found outside of these two bcrs.Most of these patients were analyzed by long distance inverse (LDI)- or multiplex-PCR which only cover bcr1. More recently, we used targeted KMT2A-NGS with whole gene coverage in over 450 patients, which was initially applied selectively in patients negative by LDI- and multiplex-PCR and then used more widely.Within the KMT2A-NGS group, 410 patients had bcr1 breakpoints mainly between the KMT2A exons 7 and 13, while 46 patients bcr2 breakpoints mainly between exons 20 and 24. Of note, five patients had their breakpoint outside of these two bcrs: three of them within intron 2 and no functional KMT2A rearrangement; the other two within intron 35 and intron 36, fusing almost the whole KMT2A gene in frame to the respective partner genes ARHGEF12 and MLLT4. These two breakpoints may define a third and rare bcr (bcr3), although further cases are needed to support this hypothesis. Interestingly, 70 patients displayed a 3‘-KMT2A deletion, indicating that the number of terminal deletions is higher than described previously. Two patients had a 5‘-KMT2A deletion. All deletions started or ended in bcr1 and bcr2.We also observed a striking difference in the distribution of partner genes between bcr1 and bcr2. The most frequent translocation partners fused to bcr1 sites are transcription factors, while the partner genes linked to bcr2 sites generally code for cytosolic proteins. In bcr1, the 4 most frequent partner genes AFF1, MLLT3, MLLT1, and MLLT10, found in 80% of cases, all code for transcription factors that are part of the super elongation complex (SEC). These fusions therefore all lead to disruption of the hematopoietic lineage commitment.In contrast in bcr2, 3 partner genes USP2, MLLT4, and USP8 account for 85% of the cases. USP2 and USP8 are ubiquitin specific peptidases involved in cell signaling and exclusively fused to bcr2 in KMT2A. While MLLT4 is found as a partner in bcr1, bcr2 and bcr3 fusions; unlike other recurrent KMT2A partners linked to bcr1, it is not a transcription factor and it exerts oncogenic potential via dimerization like other cytosolic partners. We hypothesize that the oncogenic properties of USP2 and USP8 are dependent on dimerization like MLLT4 and that the most frequent fusions involving at different bcrs favor different oncogenic mechanisms: bcr1 transactivation and bcr2 dimerization. Further studies are needed to explain why USP2 and USP8 are exclusively associated with bcr2, and why the most frequent partner genes AFF1 and MLLT3 of the bcr1 are less frequent in bcr2.In conclusion, targeted NGS combined with bioinformatic analysis has expanded our knowledge of the KMT2A recombinome to include more fusion partners and has generated new hypotheses for future research on oncogenic mechanisms. DisclosuresNo relevant conflicts of interest to declare.

Whole genome sequencing demonstrates substantial pathophysiological differences of MYC rearrangements in patients with plasma cell myeloma and B-cell lymphoma

MYC rearrangements (MYCr) occur in several B-cell neoplasms and impact disease progression and overall survival. We used whole genome sequencing (WGS) and whole transcriptome sequencing (WTS) to analyze and compare MYCr in different B-cell neoplasms. The MYCr features of cases with plasma cell myeloma (PCM) (n = 88) showed distinct characteristics compared to cases with mature B-cell lymphomas (n = 62, including Burkitt lymphoma (BL), diffuse large B-cell lymphoma (DLBCL) and high grade lymphoma with MYC and BCL2 and/or BCL6 rearrangements (HGBL)): they were more complex and showed a wider variety of translocation partners and breakpoints. Additionally, unlike B-cell lymphomas, they showed no evidence of activation-induced deaminase (AID) involvement in the formation of MYCr with immunoglobolin heavy chain (IGH), indicating a different mechanism of origin. The different MYCr characteristics resulted in poor MYCr detection rates by fluorescence in situ hybridization of only 50% in PCM, compared to 94% in lymphoma.

AF10 Fusion Transcripts Are Identified By HOXA9/10 and MEIS1 Overexpression In T-ALL: A Report From Children's Oncology Group AALL0434

The AF10 (MLLT10) gene can be fused to the CALM (10p13-14) or mixed-lineage leukemia (MLL; 11q23) genes, in patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) by complex rearrangements of chromosomes 10 and 11. Oncogenic fusion proteins produced by recurrent chromosomal translocations involving MLL or AF10 genes produce aberrant transcription factors, the expression of which typically leads to upregulation of HOXA cluster genes and their co-factors. HOXA9 has been correlated with poor prognosis in AML and B-ALL. We hypothesized that the HOXA9/10 and MEIS1 gene expression signature might identify cases of T-ALL with AF10 fusion transcripts. Because the HOXA9/10 and MEIS1 gene expression signature is not known to specifically detect AF10 fusions, we performed fluorescence in situ hybridization (FISH) using a custom AF10 break-apart probe (BAP) on 98 T-ALL cases from the Children's Oncology Group (COG) AALL0434 study. We identified 7 cases (∼7%) with AF10 rearrangements (AF10-R) that were further tested using a custom AF10/CALM double fusion FISH (D-FISH) probe. Four cases were found to have AF10-CALM fusion, one case had no fusion to CALM suggesting the presence of a different translocation partner, and two cases require further characterization. Using the Affymetrix U133 Plus 2.0 microarray to assess gene expression, we examined HOXA9/10 and MEIS1 expression in 102 T-ALL cases from COG AALL0434. Following Robust Multi-array Average (RMA) normalization and Recognition of Outliers by Sampling Ends (ROSE) analysis, we found that all seven AF10-R cases were associated with overexpression of HOXA9/10 and/or MEIS1 genes. In combination with previously reported 9 MLL-R cases in the cohort of 102 cases from COG AALL0434 study (Matlawska-Wasowska et al., 2012, ASH poster #2505), we report that at least 16% of patients in our series have MLL or AF10 rearranged T-ALL. These rearrangements are more common than previously appreciated, suggesting that HOXA overexpression may be a valid therapeutic target in T-ALL. Disclosures:No relevant conflicts of interest to declare.

High-Risk Myeloma Is Demarcated By Immunoglobulin Lambda Light Chain Translocations

Multiple myeloma is the second most common hematological malignancy, and is the consequence of uncontrolled proliferation of antibody-secreting B cells, known as plasma cells. Myeloma causes lytic bone lesions and renal failure and is characterized by heterogeneous genetic mutations and clonal selection. Subsequently, understanding the complex mutational repertoire in the context of myeloma prognosis remains challenging. We report the translocation architecture of 826 newly diagnosed myeloma patients as part of the Clinical Outcomes in Multiple Myeloma to Personal Assessment (CoMMpass) study. These data are compared to other genetic mutations, gene expression, and patient outcome to better understand high-risk disease.Whole genome sequencing identified 31% of newly diagnosed myelomas as containing an Immunoglobulin heavy chain (IgH) translocation. The vast majority of IgH translocations occurred with CCND1, WHSC1, MYC, or MAF; all of which were upregulated upon translocation. IgH-CCND1 translocations were more likely to express low levels of IgH (25%), but the majority expressed high levels of IgG1 consistent with other myelomas. Conversely, IgH-WHSC, -MYC, and -MAF translocations were more likely to express IgA (31%) and only IgH-MAF translocated myeloma expressed IgA2. IgH translocations primarily occurred at sites of class-switch recombination except for IgH-MYC translocations that originated from IgH intergenic enhancers suggesting that these occur by a distinct mechanism.MYC translocations occurred in 18% of myelomas and in contrast to IgH, MYC translocation partners were scattered throughout the genome at regions proximal to highly expressed genes. MYC translocations corresponded with MYC amplification which was present in 15% of myelomas, yet half of these contained a translocation. Both types of genetic abnormalities corresponded with increased MYC expression, but neither MYC amplification and/or translocation, nor IgH translocation were prognostic of outcome.Immunoglobulin lambda light chain (IgL) translocations were the most common translocation (7.1%) that did not involve IgH or MYC. Unlike IgH and MYC translocations, IgL translocations were prognostic of poor progression-free and overall survival. IgL translocations occurred at IgL enhancers and most commonly involved MYC, MAP3K14, 6p24.3, CCND (1,2, and 3), and MAF. IgL translocated patients presented myeloma at a similar age and stage and were treated with similar therapies as compared to other patients. IgL translocated myelomas contained a mutational repertoire that mimicked other myelomas and poor prognosis was independent of the IgL translocation partner, suggesting that the prognostic effect was intrinsic to IgL. Interestingly, myelomas with IgL translocations expressed lower levels of inflammatory cytokines including CCL3 and CCL4, suggesting they are less likely to induce anti-tumor innate immune responses. Taken together these data have important insights into myeloma pathology and implications for identifying high-risk myeloma. DisclosuresBoise:Eli Lilly and Company: Research Funding; Abbvie: Consultancy.

Comprehensive Genomic Characterization of Refractory Multiple Myeloma Reveals a Complex Mutational and Structural Landscape Associated with Drug Resistance

Comprehensive Genomic Characterization of Refractory Multiple Myeloma Reveals a Complex Mutational and Structural Landscape Associated with Drug Resistance

Deletion of Rhoh Accelerates Development of Diffuse Large B Cell Lymphoma in Bcl-6 Transgenic Mouse Model

Diffuse large B cell lymphoma (DLBCL) is an aggressive malignancy of mature B lymphocytes, accounting for 30%-40% of cases of non-Hodgkin's lymphoma. DLBCL has been classified by gene expression profiling into three subtypes GC-B-cell like (GCB)-DLBCL, activated B-cell like (ABC)-DLBCL and primary mediastinal B cell lymphoma (PMBL) or by immunohistological analysis into two subtypes, GCB-DLBCL and non-GCB- DLBCL. Rho H, a hematopoietic-specific Rho GTPase is required for CD3-zeta phosphorylation and recruitment of the protein tyrosine kinases Zap70 and Lck to the cellular membrane and immunologic synapse (Gu et al. Nat Immunol. 2006). Therefore, Rho H deficient (Rhoh-/-) mice exhibit T-cell deficiency due to impaired T-cell receptor-mediated selection and maturation of thymocytes. RHOH was first identified as a hypermutable gene and translocation partner in human B cell malignancies (Dallery E, et al . Oncogene. 1995) and RHOH mutations have been reported in 35 of 100 DLBCL cases (Hiraga J, et al. Leukemia. 2007). However, the effect of RHOH mutations and translocations on RHOH expression and the biology of lymphoma are completely unknown.We crossed Rhoh-/- and the DLBCL mouse model Iµ-HABcl-6 transgenic mouse (Cattoretti G, et al. Cancer Cell. 2005) to generate Rhoh-/- ;Bcl-6Tg and RhohWT;Bcl-6Tg mouse, and compared outcomes of these groups. Rhoh-/-; Bcl-6Tg mice developed severe splenomegaly and succumbed to disease more quickly compared with RhohWT; Bcl-6Tg mice (Figure1, Log-rank test p<0.01). Histological examination showed loss of splenic architecture and invasion of large, heterogenous lymphoid cells resembling human DLBCL. In contrast to RhohWT; Bcl-6Tg mice immunohistochemistry showed that RhohKO lymphoma cells were uniformly and strongly positive for IRF4 suggesting that loss of Rho H alters the phenotype of lymphoma at the cellular level to a ABC-DLBCL-like phenotype. Moreover, the number of Ki-67 positive cells showed a 2.5-fold increase in the spleens of Rhoh-/- lymphoma mice compared to RhohWT lymphoma mice (p<0.05). Cleaved Caspase-3, an indicator of apoptosis, was not significantly different between Rhoh-/- and RhohWT lymphoma cells. Western blot analysis of lymphoma cells showed that expression of BCL-6 was consistently increased in Rhoh-/- lymphoma cells compared with RhohWT lymphoma cells while expression of RelA/p65, NF-κB subunit, was upregulated in nuclear fraction of both Rhoh-/- and RhohWT lymphoma cells. Finally, expression of BLIMP-1, a key transcription factor associated with differentiation of B cells into plasma cells, was downregulated in Rhoh-/- lymphoma cells. We conclude that deletion of Rhoh in BCL6-driven DLBCL leads to ABC-DLBCL-like phenotype in this model of lymphoma associated with increased proliferation and more rapid progression of disease. These results support a role for Rho H mutations in the development of diffuse large B cell lymphoma. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Stratification By MYC Protein Expression Level Improves the Prognostic Impact of MYC Translocation in Patients with Large B-Cell Lymphoma

Introduction: In patients with Large B-cell Lymphoma (LBCL) the prognostic significance of MYC translocations is not clearly established. We aimed to investigate if additional identification of MYC translocation partner gene and/or MYC and BCL2 protein expression levels could improve patient prognostication associated with MYC translocations. We also wanted to evaluate the prognostic effect of double hit MYC + BCL2/BCL6 translocation (DH) compared to MYC single hit (SH).Methods: A consecutively collected training cohort of 64 patients and an independent validation cohort of 28 patients all with MYC translocation positive LBCL were investigated. Translocations were identified with fluorescent in situ hybridization (FISH) and MYC and BCL2 protein expression with immunohistochemistry (IHC).Results: MYC> 75% was seen in 50% of patients and was related to frequent bone marrow involvement, high IPI and elevated LDH. MYC>75% was also significantly associated with reduced progression free survival (PFS) and overall survival (OS) in univariate analysis (PFS: HR 6.8 (95%CI 1.5-31), p=0.004. OS: HR 4.3 (95%CI 0.9-21), p=0.05) (Fig. 1). In multivariable analysis adjusting for IPI MYC>75% was independently prognostic for PFS but not OS (PFS: HR 5.4 (95%CI 1.1-25), p=0.04. OS: HR 3.1 (95%CI 0.6-16), p=0.2). DH was seen in 71% of patients and did not confer a worse outcome compared to MYC SH. Immunoglobulin (IG) MYC translocation partner gene was found in 55% and was related to MYC protein expression levels (p=0.047). Translocation partner gene was not prognostic for PFS (p=0.8) or OS (p=0.6). High BCL2 expression was related to high MYC expression (p=0.003) and did not add to the prognostic effect observed for MYC. The findings were confirmed in a comparable, independent validation cohort of 28 MYC translocation positive LBCL. The patients included in the survival analyses were treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) or R-CHOEP (R-CHOP + etoposide).Conclusions: These findings suggest that stratification by MYC protein expression level significantly improves the prognostic impact of MYC translocation in patients with large B-cell lymphoma. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

CCG 1953: Acute Lymphoblastic Leukemia in Infants: Analysis of Prognostic Factors: A Report from the Children's Oncology Group.

Background: Infant ALL has a poor therapeutic outcome. In contrast to other subtypes of ALL, infants have not benefited from risk-adapted therapy and intensification of therapy. This is the first cooperative group trial characterizing all infants at the molecular level for MLL/11q23 rearrangements for better stratification in future trials.Procedure: All infants enrolled on CCG 1953 were tested for MLL rearrangement by Southern Blot, and the 11q23 translocation partner was identified (4;11, 9;11, 11;19, or “other”) by reverse-transcriptase PCR.Results: 115 infants were enrolled (July 1996 to August 2000). Treatment for patients consisted of 4 courses of induction-consolidation-intensification followed by 3 cycles of intensified maintenance and 4 cycles of routine maintenance. Infants with 11q23/MLL abnormalities and a protocol-defined 5-6/6 related or unrelated donor identified within 4 months were assigned to BMT. Central nervous system prophylaxis consisted of triple intrathecal therapy during the first 10 weeks of therapy. Infants not undergoing BMT received additional CNS prophylaxis with very high dose methotrexate. Patients then received one year of intensified maintenance, followed by a year of standard maintenance. Overall event-free survival (EFS) was 41.7% (SD = 9.2%) and overall survival (OS) was 44.8% at 5 years. Five-year EFS for MLL rearranged cases was 33.6%, and for MLL non-rearranged cases was 60.3% (p=.006). 5-year EFS for MLL/11q23 subgroups was as follows: t(4;11): 29.0%; t(11;19): 30.0%; t(9;11): 22.2%; and “other 11q23” 53.5% (p=.122). Multivariate Cox regression analyses showed a rank order of significance for negative impact on prognosis for CD10 negativity, age less than 6 months, and MLL rearrangement, in that order. We did not observe a statistically significant difference in outcome between different MLL translocation partners, though we did observe a non-significant trend toward improved outcome in patients with “other” MLL translocation partners as compared to those with t(4;11), t(9;11) or t(11;19). Toxicity was the most frequent cause of death. Relapse as a first event in 1953 was later (median 295 days) compared to the predecessor1883 infant ALL trial (median 207 days).Conclusions: MLL/11q23 rearrangement, CD10 expression, and age are important prognostic factors in infant ALL, but individual molecular 11q23 translocation partners do not predict outcome. These results indicate that certain subgroups have an unusually poor outcome and are therefore candidates for novel therapeutic approaches in first remission. Given the high mortality, further dose intensification strategies are unlikely to result in better long-term survival.

Concomitant mutation status of ALK-rearranged non-small cell lung cancers and its prognostic impact on patients treated with crizotinib.

BackgroundIn non-small cell lung cancer (NSCLC), anaplastic lymphoma kinase (ALK) rearrangement characterizes a subgroup of patients who show sensitivity to ALK tyrosine kinase inhibitors (TKIs). However, the prognoses of these patients are heterogeneous. A better understanding of the genomic alterations occurring in these tumors could explain the prognostic heterogeneity observed in these patients.MethodsWe retrospectively analyzed 96 patients with NSCLC with ALK detected by immunohistochemical staining (VENTANA anti-ALK(D5F3) Rabbit Monoclonal Primary Antibody). Cancer tissues were subjected to next-generation sequencing using a panel of 520 cancer-related genes. The genomic landscape, distribution of ALK fusion variants, and clinicopathological characteristics of the patients were evaluated. The correlations of genomic alterations with clinical outcomes were also assessed.ResultsAmong the 96 patients with immunohistochemically identified ALK fusions, 80 (83%) were confirmed by next-generation sequencing. TP53 mutation was the most commonly co-occurring mutation with ALK rearrangement. Concomitant driver mutations [2 Kirsten rat sarcoma viral oncogene homolog (KRAS) G12, 1 epidermal growth factor receptor (EGFR) 19del, and 1 MET exon 14 skipping] were also observed in 4 adenocarcinomas. Echinoderm microtubule associated protein-like 4 (EML4)-ALK fusions were identified in 95% of ALK-rearranged patients, with 16.2% of them also harboring additional non–EML4-ALK fusions. Nineteen non-EML4 translocation partners were also discovered, including 10 novel ones. Survival analyses revealed that patients concurrently harboring PIK3R2 alterations showed a trend toward shorter progression-free survival (6 vs. 13 months, P=0.064) and significantly shorter overall survival (11 vs. 32 months, P=0.004) than did PIK3R2-wild-type patients. Patients with concomitant alterations in PI3K the signaling pathway also had a shorter median overall survival than those without such alterations (23 vs. 32 months, P=0.014), whereas progression-free survival did not differ significantly.ConclusionsThe spectrum of ALK-fusion variants and the landscape of concomitant genomic alterations were delineated in 96 NSCLC patients. Our study also demonstrated the prognostic value of concomitant alterations in crizotinib-treated patients, which could facilitate improved stratification of ALK-rearranged NSCLC patients in the selection of candidates who could optimally benefit from therapy.

Rationale for Early Detection of EWSR1 Translocation-Associated Sarcoma Biomarkers in Liquid Biopsy.

Simple SummaryTumour cells often spread from the primary site to new tissues in a process known as metastasis. It has been demonstrated that there is a relationship between the number of circulating tumour cells in the blood and the tumour burden in patients with some forms of sarcoma, which is a cancer of bone and connective tissue. Sarcomas have a particular bias towards metastasis via the blood stream, which is able to be sampled relatively non-invasively, and many forms of sarcoma have well-characterised biomarkers that distinguish them from other blood cells. These characteristics potentiate the use of blood for ‘liquid biopsies’ for patients who are in remission, to detect a relapse as early as possible. This review summarises developments for sarcomas that are associated with the translocation of EWSR1 and similar genes.Sarcomas are mesenchymal tumours that often arise and develop as a result of chromosomal translocations, and for several forms of sarcoma the EWSR1 gene is a frequent translocation partner. Sarcomas are a rare form of malignancy, which arguably have a proportionally greater societal burden that their prevalence would suggest, as they are more common in young people, with survivors prone to lifelong disability. For most forms of sarcoma, histological diagnosis is confirmed by molecular techniques such as FISH or RT-PCR. Surveillance after surgical excision, or ablation by radiation or chemotherapy, has remained relatively unchanged for decades, but recent developments in molecular biology have accelerated the progress towards routine analysis of liquid biopsies of peripheral blood. The potential to detect evidence of residual disease or metastasis in the blood has been demonstrated by several groups but remains unrealized as a routine diagnostic for relapse during remission, for disease monitoring during treatment, and for the detection of occult, residual disease at the end of therapy. An update is provided on research relevant to the improvement of the early detection of relapse in sarcomas with EWSR1-associated translocations, in the contexts of biology, diagnosis, and liquid biopsy.

Mantle cell lymphomas with concomitant MYC and CCND1 breakpoints are recurrently TdT positive and frequently show high-grade pathological and genetic features.

Chromosomal breakpoints involving the MYC gene locus, frequently referred to as MYC rearrangements (MYC - R+), are a diagnostic hallmark of Burkitt lymphoma and recurrent in many other subtypes of B-cell lymphomas including follicular lymphoma, diffuse large B-cell lymphoma and other high-grade B-cell lymphomas and are associated with an aggressive clinical course. In remarkable contrast, in MCL, only few MYC - R+ cases have yet been described. In the current study, we have retrospectively analysed 16 samples (MYC - R+, n = 15, MYC - R-, n = 1) from 13 patients and describe their morphological, immunophenotypic and (molecular) genetic features and clonal evolution patterns. Thirteen out of fifteen MYC - R+ samples showed a non-classical cytology including pleomorphic (centroblastic, immunoblastic), anaplastic or blastoid. MYC translocation partners were IG-loci in 4/11 and non-IG loci in 7/11 analysed cases. The involved IG-loci included IGH in 3 cases and IGL in one case. PAX5 was the non-IG partner in 2/7 patients. The MYC - R+ MCL reported herein frequently displayed characteristics associated with an aggressive clinical course including high genomic-complexity (6/7 samples), frequent deletions involving the CDKN2A locus (7/10 samples), high Ki-67 proliferation index (12/13 samples) and frequent P53 expression (13/13 samples). Of note, in 4/14 samples, SOX11 was not or only focally expressed and 3/13 samples showed focal or diffuse TdT-positivity presenting a diagnostic challenge as these features could point to a differential diagnosis of diffuse large B-cell lymphoma and/or lymphoblastic lymphoma/leukaemia.

ALK-positive diffuse large B-cell lymphoma is associated with Clathrin-ALK rearrangements: report of 6 cases

AbstractExpression of ALK protein by lymphoid cells and the description of variant anaplastic lymphoma kinase (ALK) translocations have typically been restricted to cases of T-cell and null anaplastic large-cell lymphoma (ALCL). All such cases result from a novel fusion created by the ALK gene on chromosome 2p23 and NPM on 5q35 or other variant translocation partners. A rare variant of diffuse large B-cell lymphoma (DLBCL), originally described in 1997, was thought to overexpress full-length ALK in contrast to a chimeric protein characteristic of ALCL. However, full-length ALK protein lacks tyrosine kinase activity and thus the mechanism of oncogenesis has remained elusive. We describe 6 cases of ALK+ DLBCL characterized by a simple or complex t(2;17)(p23;q23) involving the clathrin gene (CLTC) at chromosome band 17q23 and the ALK gene at chromosome band 2p23. All cases were studied using fluorescence in situ hybridization (FISH), complemented in one case with standard cytogenetic analysis, multicolor karyotyping (M-FISH), and reverse transcriptase-polymerase chain reaction. These results clearly demonstrate that most cases of ALK+ DLBCL share the same mechanism of deregulated ALK expression. Moreover, these results demonstrate the presence of CLTC-ALK fusions in these tumors and extend the list of diseases associated with this genetic abnormality to include classical T-cell or null ALCL, ALK+ DLBCL, and inflammatory myofibroblastic tumors. (Blood. 2003;102:2568-2573)

The Molecular Characteristics and Clinical Relevance of NUP98-Other Translocations in Pediatric Acute Myeloid Leukemia

Background Cytogenetic and molecular aberrations are important prognostic factors in pediatric acute myeloid leukemia (AML). NUP98 translocations with more than 30 different partner genes have been identified in pediatric AML. The 2 most common fusions, NUP98-NSD1 and NUP98-KDM5A, have been shown to have distinct characteristics and are both associated with adverse outcomes. Although NUP98 fusions with less common fusion partners have been identified, the biological and clinical implications of these variants are unknown. Methods To determine the biological and clinical implications of the less common "other" NUP98 translocations (NUP98-X), we evaluated the clinical characteristics and transcriptome and genome sequencing data from 2396 children and young adults with AML within 4 consecutive Children's Cancer Group (CCG) and Children's Oncology Group (COG) trials CCG-2961, AAML03P1, AAML0531 and AAML1031. All NUP98-X translocations were confirmed by RNA sequencing. Results Of the 2396 patients screened, 164 patients (6.8%) had a NUP98 translocation. We identified 20 patients with a NUP98-X fusion (0.83%) and compared them with those with NUP98-NSD1 (n=110, 4.5%), NUP98-KDM5A(n=34, 1.4%), and a reference cohort without NUP98 translocations (n=2232). Translocation partners identified in the NUP98-X group were HOXA9 (n=4), HOXD13 (n=3), PHF15 (n=2), PHF23 (n=2), and single cases of BPTF, BRWD3, DDX10, HMGB3, HOXA13, KAT7, PRRX1, SET and TOP1. Besides the distinct characteristics of NUP98-NSD1 and NUP98-KDM5A, the NUP98-X group showed high inter-patient variance in clinical characteristics compared to our reference cohort. NUP98-X patients showed a clear bimodal age distribution with half of the patients being in the older age category and a similar number in the category &amp;lt;3 years (Figure 1). White blood cell count and blast percentages were in line with those of the reference cohort. We investigated the co-occurrence of common pediatric AML mutations within our cohort (Figure 2). There was a lack of additional driving mutations with the exception of WT1 mutations that are significantly more prevalent in the NUP98-X group compared to the reference cohort (25% vs 8%, p=0.018). NUP98-X patients with a WT1 mutation have a median age of 16.3 years compared to 2.3 years for those without a WT1 mutation. Also, in contrast to NUP98-NSD1 translocated patients, the co-occurrence of FLT3-ITD did not occur in NUP98-X translocated patients. Further, NUP98-X patients had a more varied transcriptome profile than did patients with NSD1 or KDM5A translocations (Smith J, et al. ASH abstract 2020). We evaluated the impact of NUP98-X translocations in response to the initial induction therapy. The morphological complete remission (CR) rate after course 1 was 65% in the NUP98-X cohort versus 76% in the reference cohort (p=0.266). NUP98-NSD1 patients had an inferior CR rate (36%, p&amp;lt;0.001), but the CR rate in NUP98-KDM5A patients was similar (77%) to the reference cohort. Of all NUP98-X patients, 11% underwent stem cell transplantation (SCT), compared to 17% in the reference cohort, 40% in the NUP98-NSD1 and 23% in the NUP98-KDM5A cohort. Outcome analysis for NUP98-X patients demonstrated that despite differences in disease characteristics, they have similar adverse outcomes as patients with NSD1 or KDM5A translocations (Figure 3). Overall survival (OS) at 5 years from diagnosis was 35% compared to 65% in the group without NUP98 translocations (p=0.006, Figure 3). Event-free survival was 35% for NUP98-X patients, compared to 48% for those without NUP98 translocations (p=0.282). These adverse outcome rates are comparable to those reported in studies on high-risk pediatric AML patients. Conclusion NUP98-X translocated pediatric AML patients represent a rare cohort with a high variability in both translocation partners and other clinical characteristics. Despite this heterogeneity, the OS of these patients is comparable to high-risk pediatric AML patients, which justifies a high-risk stratification of these patients and emphasizes the need for developing new treatment strategies. Further research within large patient cohorts is needed to investigate the biologic and clinical characteristics of these rare translocations and potential differences between the different NUP98-X fusion partners. Disclosures Kaspers: AbbVie: Ended employment in the past 24 months; Helsinn Healthcare: Ended employment in the past 24 months; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees; Janssen R&amp;D: Ended employment in the past 24 months. Cooper:Celgene: Other: Spouse was an employee of Celgene (through August 2019).

Characterizing Proteins That Mediate CALM-AF10 Leukemogenesis

Background: Leukemia is the most common type of childhood cancer. Although the prognosis for many pediatric leukemias has improved, leukemias associated with the t(10;11) CALM-AF10 translocation remain difficult to treat. CALM-AF10 leukemias account for ~5-10% of childhood T-cell acute lymphoid leukemia (T-ALL) as well as a subset of acute myeloid leukemia (AML). CALM-AF10 leukemias exhibit increased expression of proleukemic HOXA genes, but relatively little is known about the cellular mechanisms that drive CALM-AF10 leukemogenesis. Our laboratory has demonstrated that the CALM protein contains a nuclear export signal (NES) that is critical for CALM-AF10-dependent leukemogenesis. The NES interacts with the CRM1/XPO1 nuclear export receptor, which shuttles proteins from the nucleus to the cytoplasm through the nuclear pore complex. We have shown that transcriptional activation of HOXA genes by CALM-AF10 is critically dependent on its interaction with CRM1. Importantly, CRM1 does not contain a recognized DNA binding domain, and it is not currently understood how the CALM-AF10/CRM1 complex interacts with regulatory regions of HOXAgenes. In order to identify proteins that mediate the interaction between the CALM-AF10/CRM1 complex and DNA, we took advantage of a proximity-based labeling approach using BioID2, a second-generation biotin ligase. When fused to a protein of interest and in the presence of biotin, BioID2 biotinylates proteins in close proximity to the ligase. These biotinylated proteins can then be identified by mass spectrometry (MS). Methods: We prepared an expression plasmid in which BioID2 was cloned in-frame with CALM-AF10. We then transiently transfected Human Embryonic Kidney 293 (HEK293) cells with the BioID2-CALM-AF10 plasmid, grew them in the presence or absence of biotin, and performed streptavidin-pulldown followed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) to identify candidate interacting proteins. Proteins were considered candidates if they had a peptide spectrum match (PSM) score &amp;gt; 10 and at least a two-fold greater PSM score versus negative control. We validated direct interactions of candidate proteins with CALM-AF10 by performing co-immunoprecipitation experiments. Results: We first confirmed that the addition of BioID2 to CALM-AF10 does not affect the transcriptional activation of HOXA genes or CALM-AF10 mediated immortalization of hematopoietic stem cells. We carried out three independent transfections/LC-MS/MS experiments, which identified 71, 95 and 61 proteins, respectively. Of the proteins identified, 11 candidates were common to all three experiments.Of particular interest, we identified Disruptor Of Telomeric silencing 1-Like (DOT1L), a protein known to interact with AF10, and Nuclear pore complex protein 214 (NUP214), a protein that has been identified in leukemogenic translocations. The nine additional candidate proteins included: EPS15, DVL2, DVL3, and DDX3X -all known to play a role in leukemogenesis. We performed initial validation of direct interactions via co-immunoprecipitation and found that Epidermal Growth Factor Receptor Substrate 15(EPS15) co-precipitates with CALM-AF10. Conclusion: We used biotin ligase-dependent proximity-based labeling to identify candidate proteins that potentially interact with the CALM-AF10 fusion protein. Our identification of DOT1L validates the approach, since DOT1L is known to interact with CALM-AF10. We have started to investigate other candidate proteins, focusing on known translocation partners in various leukemias. Our screen identified EPS15, a protein involved in receptor-mediated endocytosis of epidermal growth factor and a known translocation partner for MLL/KMT2A. KMT2A-EPS15 translocations (t(1;11)(p32;q23)) have been identified in both AML and ALL, and KMT2A-EPS15 is among the eight most common KMT2A rearrangements. We have shown that EPS15 co-immunoprecipitates with CALM-AF10, suggesting that EPS15 may also play a role in CALM-AF10 leukemogenesis. Further evaluation of this interaction is underway, and may lead to identification of novel pathways involved in CALM-AF10 leukemogenesis. Disclosures No relevant conflicts of interest to declare.

Outcome of (Novel) Subgroups in 1257 Pediatric Patients with KMT2A-Rearranged Acute Myeloid Leukemia (AML) and the Significance of Minimal Residual Disease (MRD) Status: A Retrospective Study By the I-BFM-SG

Introduction Outcome of KMT2A-rearranged (KMT2A-r) pediatric AML (pAML) is in general poor with a 5-year probability of event-free survival (5y-pEFS) and overall survival (5y-pOS) of 44% and 56%, respectively (Balgobind et al., 2009). However, over the past decades, the heterogeneity of KMT2A-r pAML has emerged, showing differences in outcome between subgroups based on translocation partners. The predictive value of MRD in KMT2A-r pAML is undefined. This retrospective study aimed to confirm the outcome of pediatric KMT2A subgroups (Balgobind et al., 2009) in a more recent era and to study the significance of MRD status during and after induction. Methods Outcome and MRD data of 1257 KMT2A-rde novo pAML patients from 15 AML groups affiliated with the I-BFM-AML study group, diagnosed between 2005 and 2016 were retrospectively collected. Patients were assigned to KMT2A subgroups, or to the KMT2A-other group in case of unknown translocation partner. Flow cytometry MRD levels &amp;lt;0.1% were considered negative, and levels ≥0.1% positive. Kaplan-Meier methods were used to estimate probabilities of disease-free survival (pDFS), pEFS and pOS. Cox regression analyses were performed to study the independent impact of KMT2A subgroups and potentially prognostic factors: white blood cell count (WBC), age and MRD status. Results The 1257 patients were assigned to 13 KMT2A subgroups, or the KMT2A-other group. Two novel subgroups were identified: t(X;11)(q24;q23) (n=21, 2%) and t(1;11)(p32;q23) (n=12, 1%). The median age was 2.5 years (range, 0-18.9). The median WBC was 21.4 x 109/L (range, 0.2-727). Overall complete remission rate was 91%. The 5y-pEFS was 46% [SE, 2%] and the 5y-pOS was 62% [SE, 2%]. Differences across subgroups in 5y-pEFS (Figure 1) ranged from 24% [SE, 5%] to 76% [SE, 9%], and in 5y-pOS from 25% [SE, 13%] to 92% [SE, 8%] (both p&amp;lt;0.0001). The median follow-up time of patients at risk was 5 years. The subgroups t(10;11)(p12;q23) (HR 1.7, p&amp;lt;0.0001), t(6;11)(q27;q23) (HR 1.9, p&amp;lt;0.0001), t(4;11)(q21;q23) (HR 2.9, p=.003) and t(10;11)(p11.2;q23) (HR 2.7, p&amp;lt;0.0001), WBC of &amp;gt;100 x 10^9/L (HR 1.3, p=.006), and age &amp;gt;10y (HR 1.3, p=.005) were revealed as independent predictors of poor EFS. These factors also predicted OS. MRD data after induction course one were available for n=635 (MRD-positivity (range, 0.1-94) n=126, 20%) and after course two for n=527 (MRD-positivity (range, 0.1-88) n=51, 10%). In the four KMT2A poor-risk subgroups, MRD-positivity was not significantly more common after induction course one (p=.0232) or two (p=.066), compared with the other subgroups. MRD-positivity was associated with inferior 5y-pDFS after both induction course one (36% [SE, 4%] vs 48% [SE, 2%]; p=.002) and course two (28% [SE, 6%] vs 49% [SE, 2%]; p&amp;lt;0.0001) (Figure 2). Within the t(9;11)(p22;q23) subgroup, MRD-positivity after induction course one, and within the t(10;11)(p12;q23) subgroup after course two, was associated with inferior 5y-pDFS (36% [SE, 8%] vs 56% [SE, 4%]; p=.004, and 0% [SE, 0%] vs 35% [SE, 5%]; p&amp;lt;0.0001, respectively). After induction course one, the subgroups t(10;11)(p12;q23) (HR 1.7, p&amp;lt;0.0001) and t(10;11)(p11.2;q23) (HR 4.0, p&amp;lt;0.0001), and MRD-positivity (HR 1.5, p=.003) were revealed as independent predictors of poor DFS. After induction course two, the subgroups t(10;11)(p12;q23) (HR 1.8, p&amp;lt;0.0001), t(4;11)(q21;q23) (HR 4.9, p=.008) and t(10;11)(p11.2;q23) (HR 3.2, p&amp;lt;0.0001), MRD-positivity (HR 2.0, p&amp;lt;0.0001), and age &amp;gt;10y (HR 1.5, p=.002) were revealed as independent predictors of poor DFS. Within the group of patients with MRD-negativity after induction course two, the subgroups t(10;11)(p12;q23) and t(10;11)(p11.2;q23) were independent predictors of poor EFS (5y-pEFS 35%, HR 1.7, p=.003 and 5y-pEFS 18%, HR 2.7, p=.004, respectively). Conclusion Outcome for KMT2A-r pAML patients has improved slightly, but similar subgroups were identified as poor risk (Balgobind et al., 2009), including t(10;11)(p12;q23), t(10;11)(p11.2;q23) and t(6;11)(q27;q23). In our study, t(4;11)(q21;q23) was poor risk as well. These subgroups should be considered for high-risk pAML therapy protocols. The favorable risk of t(1;11)(q21;q23) could not be confirmed in our cohort. MRD status is highly predictive of outcome within KMT2A subgroups. In MRD-negative patients after induction course two, both t(10;11) KMT2A subgroups were associated with poor outcome. Disclosures Guest: Syndax Pharmaceuticals: Consultancy. Locatelli:Medac: Speakers Bureau; Miltenyi: Speakers Bureau; Bellicum Pharmaceutical: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz Pharmaceeutical: Speakers Bureau. Rubnitz:AbbVie Inc.: Research Funding. Kaspers:Helsinn Healthcare: Ended employment in the past 24 months; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees; Janssen R&amp;D: Ended employment in the past 24 months; AbbVie: Ended employment in the past 24 months.

Analysis of Racial Differences in the Incidence of a Targetable Biomarker, t(11;14), in Patients with Multiple Myeloma

Introduction Compared with Caucasian Americans (CA), African Americans (AA) have an increased incidence of multiple myeloma (MM), earlier age at diagnosis, and overall better prognosis [1]. The molecular mechanisms underlying such racial disparity are not well understood. Using targeted next generation sequencing assay or traditional fluorescence in situ hybridization (FISH) methods, previous studies reported that t(11;14) is more common in AA compared with CA with MM and monoclonal gammopathies [2,3]. However, the number of AA cases studied were small and conflicting data exists. Clinical trials in relapsed or refractory MM indicate that t(11;14) is a biomarker which may be used to predict response to a therapeutic agent (venetoclax) which targets BCL-2 [4,5]. Identifying racial differences in molecular biomarkers would be helpful in our understanding of the known racial disparities of incidence in MM and in the development of therapeutic trials. Methods 737 patients with newly diagnosed MM or smoldering myeloma (SM) at University Hospitals Seidman Cancer Center between 2009 and 2020 were identified. All had myeloma FISH panel sent at diagnosis, which included trisomy of chromosomes 3, 7, or 11, deletion 13q14.3 or loss of chromosome 13, deletion 17p13.1, 1q21 (CKS1B) amplification, and 14q32.3 rearrangements. IGH/CCND1 [t(11;14)(q13;q32)] dual fusion probe was used prior to 2018. Extra signal would trigger reflex test for IGH/FGFR3 [t(4;14)(p16.3;q32)] and IGH/MAF [t(14;16)(q32;q23)]. IGH break apart probe was used since 2018. IGH rearrangement would trigger reflex testing for translocation partners as listed above. Between-group differences were assessed with T-test for continuous variables, and Chi-square / Fisher's exact test for categorical variables. Results Of the 737 patients (661 MM, 76 SM), 502 (68.1%) were self-reported as CA, 213 (28.9%) were AA, and 22 (3.0%) were of other races or listed as unknown. Median age was 71 among CA and 70 among AA (p=0.67). The male-female ratio was 291/211 (58% male) among CA and 101/112 (47% male) among AA (p=0.0095). Overall t(11;14) was detected in 4.5% of cases, 5.2% CA and 2.8% AA (p=0.165); among 661 MM, t(11;14) was tested positive in 30/656 (4.57%), including 23 (5.1%) CAs, 6 (3.1%) AAs, and 1 others (p= 0.80); among 76 SM, t(11;14) was tested positive in 3/76 (3.95%), all were CAs. The percentages of patients who tested positive for other cytogenetic abnormalities were as follows: trisomy 3,7, or 11 was detected in 35.6% CA and 32.4% AA (p=0.42); 1q21 amplification was detected in 25.5% CA and 23.9% AA (p=0.72); deletion 13q14.3 or loss of chromosome 13 was detected in 16.5% CA and 10.7% AA (p=0.08); deletion 17p13.1 was detected in 6.4% CA and 5.2% AA (p=0.54); t(4;14) was detected in 2.8% CA and 1.4% AA (p=0.27); t(14;16) was detected in 0.4% CA and 0.5% AA (p=0.89) Conclusions This retrospective series of 737 MM and SM patients did not find an increased incidence of the targetable biomarker t(11;14) in AA patients. The overall percentage of t(11;14) cases was lower than expected. The lack of our finding a racial difference differs from some other reports, perhaps due to a fairly enriched AA population. There were also no significant racial differences found in other cytogenetic abnormalities. Further investigation at the molecular level should be performed to elucidate the mechanisms of racial disparity in MM.

Meta-Analysis of Genome-Wide Association Studies of Acute Myeloid Leukemia (AML) Patients Identifies Variants Associated with Risk of 11q23/KMT2A-Translocated and Core-Binding Factor (CBF) AML and Suggests a Role for Transcription Elongation in Leukemogenesis

Meta-Analysis of Genome-Wide Association Studies of Acute Myeloid Leukemia (AML) Patients Identifies Variants Associated with Risk of 11q23/KMT2A-Translocated and Core-Binding Factor (CBF) AML and Suggests a Role for Transcription Elongation in Leukemogenesis