Feldman, Andrew L.

Abstract Background: Peripheral T-cell lymphomas (PTCLs) comprise a group of non-Hodgkin lymphomas (NHLs) of mature T-cell origin with generally aggressive clinical behavior. Most systemic PTCLs are treated with anthracycline-based combination chemotherapy; however, outcomes remain relatively poor for most subtypes except ALK-positive anaplastic large cell lymphoma (ALCL). We have used landmark analyses based on event-free survival (EFS) to identify clinically useful endpoints in B-cell NHLs, with EFS at 24 (EFS24) months identified to stratify overall survival (OS) in aggressive B-cell NHL. Here we examined the ability of EFS24 to predict subsequent OS in a large, multinational PTCL cohort. Methods: A cohort of newly diagnosed PTCL patients treated with curative intent combination chemotherapy regimens was assembled from the University of Iowa/Mayo Clinic SPORE Molecular Epidemiology Resource (MER), Swedish Lymphoma Registry (SWE), and British Columbia Cancer Agency (BCCA). Subtypes included ALK-negative ALCL, angioimmunoblastic T-cell lymphoma (AITL), PTCL, not otherwise specified (NOS), enteropathy-associated T-cell lymphoma (EATL), extranodal NK/T-cell lymphoma, nasal type (ENKTL), and hepatosplenic T-cell lymphoma (HSTCL). Patients were followed based on local institution guidelines, and EFS was defined as time from the date of pathologic diagnosis to progression, re-treatment, or death due to any cause. EFS24 was defined as being alive and event-free 24 months from diagnosis. Subsequent OS was defined as time from achieving EFS24 (24 months from diagnosis) or time from progression in patients failing to achieve EFS24 (progression within 24 months of diagnosis). OS was compared to the age-, sex-, and country-matched general population using United States, Sweden, and British Columbia rate tables via standardized mortality ratios (SMR) and expected survival. Results: 775 patients diagnosed from 2000-2012 were included in the combined analysis with diagnosis by the WHO classification at the respective institutions (MER=138, SWE=422, BCCA=215). Median age at diagnosis was 64 years (range 18-89) and 63% were male. Patient characteristics are summarized in the table. 736 (95%) received anthracyline-based therapy at diagnosis. At a median follow-up of 77 months (range 1-185), 516 patients (67%) had died. The percentage of patients achieving EFS24 was similar across the 3 cohorts (MER=39%, SWE=35%, BCCA= 36%, combined=36%). Median survival after progression within the first 24 months was only 4.9 months (95% CI: 3.8-5.9), with a 5-year OS of 11% and SMR of 46.4 (95% CI: 41.8-51.3). In contrast, median survival after achieving EFS24 was not reached, with a 5-year OS of 78% (95% CI: 73%-84%). This was inferior to the expected survival of 92% in the age-, sex-, and country matched population (SMR=3.16; 95% CI: 2.48-3.98). In EFS24 subgroup analyses, more favorable outcomes were observed in younger patients (age <=60 years, N=137, 5-year survival of 91% vs. 98% expected) and in patients receiving autologous stem cell transplant in first remission (N=72, 5-year survival of 88% vs. 96% expected). Patients achieving EFS24 who were not transplanted in first remission (N=189) had a 5-year survival of 74% vs. 90% expected. Conclusions: Assessment of EFS24 stratifies subsequent outcome in PTCL. Patients with early relapse from PTCL have extremely poor outcomes. However, over one-third of patients with PTCL remain in remission two years from diagnosis after initial chemotherapy and have encouraging OS rates, although survival remains significantly worse than the matched general population. Subset analysis suggests that younger patients and patients who receive autologous stem-cell transplant in first CR have 5-year survival rates that approach 90%, though still below the expected survival of the background population. The marked differences in OS after failing or achieving EFS24 in PTCL patients suggest that this endpoint may be useful for patient counseling, as a clinical trial endpoint, and as an endpoint to assess novel biomarkers for risk stratification. Table Table. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Maurer: Celgene: Research Funding; Kite Pharma: Research Funding. Jerkeman:Mundipharma: Research Funding; Amgen: Research Funding; Janssen: Research Funding; Gilead: Research Funding; Celgene: Research Funding. Connors:Seattle Genetics: Research Funding; Millennium Takeda: Research Funding; NanoString Technologies: Research Funding; F Hoffmann-La Roche: Research Funding; Bristol Myers Squib: Research Funding. Ansell:BMS, Seattle Genetics, Merck, Celldex and Affimed: Research Funding.

Abstract Diffuse large B-cell lymphoma (DLBCL) is a genetically heterogeneous disease characterized by multiple low-frequency alterations including somatic mutations, copy number alterations (CNAs) and chromosomal rearrangements. We sought to identify previously unrecognized low-frequency genetic events, integrate recurrent alterations into comprehensive signatures and associate these signatures with clinical parameters. For these reasons, our multi-institutional international group assembled a cohort of 304 primary DLBCLs from newly diagnosed patients, 87% of whom were uniformly treated with state-of-the-art therapy (rituximab-containing CHOP regimen) and had long term followup. Tumors were subjected to whole exome sequencing with an extended bait set that included custom probes designed to capture recurrent chromosomal rearrangements. In this cohort, 47% of samples had available transcriptional profiling and assignment to associated disease subtypes. Analytical pipelines developed at the Broad Institute were used to detect mutations (MuTect), CNAs (Recapseq+Allelic Capseq) and chromosomal rearrangements (dRanger+Breakpointer) and assess clonality (Absolute). To analyze formalin-fixed paraffin-embedded tumors without paired normals we developed a method which utilized 8334 unrelated normal samples to stringently filter recurrent germline events and artifacts. Significant mutational drivers were identified using the MutSig2CV algorithm and recurrent CNAs were assessed with GISTIC2.0. In addition, we utilized a recently developed algorithm, CLUMPS2, to prioritize somatic mutations which cluster in 3-dimensional protein structure. With this approach, we identified > 90 recurrently mutated genes, 34 focal amplifications and 41 focal deletions, 20 arm-level events and > 200 chromosomal rearrangements in the DLBCL series. Of note, 33% of the mutational drivers were also perturbed by chromosomal rearrangements or CNAs, underscoring the importance of a comprehensive genetic analysis. In the large DLBCL series, we identified several previously unrecognized but potentially targetable alterations including mutations in NOTCH2 (8%) and TET2 (5%). The majority of identified chromosomal rearrangements involved translocations of potent regulatory regions to intact gene coding sequences. The most frequently rearrangements involved Ig regulatory elements which were translocated to BCL2, MYC, BCL6 and several additional genes with known roles in germinal center B-cell biology. After identifying recurrent somatic mutations, CNAs and chromosomal rearrangements, we performed hierarchical clustering and identified subsets of DLBCLs with comprehensive signatures comprised of specific alterations. A large subset of tumors shared recurrent alterations previously associated with follicular lymphoma including mutations of chromatin modifiers such as CREBBP, MLL2, and EZH2 in association with alterations of TNFRSF14 and GNA13 and translocations of BCL2. This cluster was enriched in GCB-type DLBCLs and contained a subset with select genetic alterations associated with an unfavorable outcome. An additional cohort of tumors was characterized by alterations perturbing B-cell differentiation including recurrent BCL6 translocations or alterations of PRDM1. A subset of these DLBCLs had alterations of NOTCH2 and additional pathway components or mutations of MYD88 in association with TNFAIP3, CD70 and EBF1, a master regulator of B-cell differentiation. An additional group of DLBCLs exhibited frequent MYD88 mutations in association with alterations of CD79B, PIM1, TBL1XR1 and ETV6 and BCL2 copy gain; these tumors were highly enriched for ABC-type DLBCLs. This coordinate signature and additional alterations of p53 pathway components were associated with outcome. We explored bases for the identified genetic alterations in DLBCL by performing an in silico mutational signature analysis. The most frequent mutational signatures were those of spontaneous deamination (aging) and AID with rare cases of microsatellite instability. We also assessed the clonality of identified genetic features to define cancer cell fraction and establish the timing of specific genetic events. The comprehensive genetic signatures of clinically annotated DLBCLs provide new insights regarding approaches to targeted therapy. Disclosures Link: Kite Pharma: Research Funding; Genentech: Consultancy, Research Funding. Rodig:Perkin Elmer: Membership on an entity's Board of Directors or advisory committees; BMS: Research Funding. Pfreundschuh:Boehringer Ingelheim, Celegene, Roche, Spectrum: Other: Advisory board; Roche: Honoraria; Amgen, Roche, Spectrum: Research Funding. Shipp:Gilead: Consultancy; Sanofi: Research Funding; BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Abstract Peripheral T- and NK-cell lymphomas (PTCLs) are fatal in the majority of patients, and conventional chemotherapy is minimally effective. Targeted inhibition of tyrosine kinases (TKs) might be a useful treatment strategy, but TK overexpression by PTCLs has not been well characterized (except ALK). Recently a novel translocation t(5;9) fusing the ITK and SYK genes was reported in a subset of unspecified-type PTCLs, associated with high SYK gene expression and Syk protein positivity. Syk is a non-receptor TK important in immunoreceptor signal transduction, providing proliferation and survival signals in a variety of hematopoietic cells. Syk is absent or expressed at very low levels in most normal post-thymic T cells, where this signal transduction role is fulfilled by ZAP70. Since Syk TK inhibitors are now in clinical trials for other diseases, we sought to determine the incidence of t(5;9) and Syk overexpression in PTCL. Tissue microarrays were constructed using triplicate cores from paraffin-embedded tissue blocks. Cases were studied using fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC). Additional studies were performed using flow cytometry and Western blot. There were 141 PTCLs, including 35 angioimmunoblastic, 66 unspecified, 21 anaplastic large cell, 2 enteropathy-associated, 5 hepatosplenic, 5 extranodal NK/T, and 7 other. No evidence of t(5;9) was identified by FISH in 86 informative cases. Normal T-cell subsets from peripheral blood, spleen, and lymph node were negative for Syk by IHC, flow cytometry, and Western blot. Syk was positive by immunohistochemistry in 133 of 141 (94%) PTCLs. All 8 Syk negative cases were extranodal, cytotoxic PTCLs. Western blot on frozen tissue correlated with IHC results in paraffin. All 4 Syk-positive cases tested showed phosphorylation of tyrosine residues 525/526, known to be required for Syk activation. We conclude that Syk is overexpressed in most PTCLs, including the vast majority of nodal cases. Syk may substitute for ZAP70 in these tumors and provide ongoing proliferation and survival signaling. The overexpression of Syk and phosphorylation of its Y525/526 residues suggest Syk may be a suitable target for pharmacologic TK inhibition as a treatment option for patients with PTCL.

Abstract Background: Follicular lymphoma (FL) is an indolent lymphoma generally considered incurable with current standard therapies. Recent advances have resulted in prolongation of overall survival (OS) for patients with FL such that death from competing causes may now limit the mortality impact of FL in some patient groups. Identification of patients for whom FL related mortality is expected to be minimal, or conversely those at high risk of disease related mortality, is highly clinically relevant. We recently reported (Maurer et al, JCO 2014;32:1066-73) that event-free survival (EFS) at 24 months from diagnosis is a robust endpoint for disease related outcome in patients with diffuse large B cell lymphoma (DLBCL). Here we use the same approach to assess if landmark timepoints of EFS can stratify subsequent OS in FL. Methods: All newly diagnosed grade 1-3a FL patients enrolled on the University of Iowa/Mayo Clinic Lymphoma SPORE Molecular Epidemiology Resource (MER) from 2002-2011 were eligible. Patients with grade 3b FL, transformation, or presence of DLBCL at diagnosis were excluded. EFS was defined as time from diagnosis to progression, relapse, re-treatment, or death due to any cause. EFS12 was defined based on EFS status 12 months after date of diagnosis; we also assessed EFS at 24 months. OS was defined as time from a specific timepoint (diagnosis, event, or EFS12) until death due to any cause. OS was compared to age and sex matched survival in the general US population using an expected survival approach and standardized mortality ratios (SMR) and 95% confidence intervals (CI). Outcomes were examined in all patients as well as selected subsets defined by initial treatment. Replication was performed using a Lyon, France hospital registry of newly diagnosed grade 1-3a FL patients enrolled from 2002-2010 with survival compared to French population data. Results: 936 patients with grade 1-3a FL were eligible from the MER. The median age at diagnosis was 60 years (range 19-91) and 53% were male. 86% had grade 1-2 disease and 14% grade 3a disease. 23% had high-risk disease (FLIPI score ≥3). 347 (37%) were initially treated with alkylator or anthracyline based immunochemotherapy (IC), 113 (12%) rituximab monotherapy (RM), and 318 (34%) were initially observed; the remaining patients received radiation for limited stage disease (8%), chemotherapy without rituximab (4%), or other therapy (5%). At a median follow-up of 59 months (range 1-131), 403 patients (43%) had an event and 120 patients (13%) had died; 155 patients (17%) failed to achieve EFS12. From diagnosis, patients with FL had inferior OS compared to the general population (SMR=1.24, 95% CI: 1.03-1.48, p=0.018); results were similar for patients with grade 1-2 (SMR=1.23) and grade 3a (SMR=1.29) disease. The survival deficit was eliminated in patients who achieved EFS12 (SMR=0.85, 95% CI: 0.66-1.09, p=0.20, Fig 1a), and so we did not pursue modeling EFS24. In contrast, patients with a non-death event (relapse, retreatment, or progression) within 12 months of diagnosis had inferior subsequent OS (SMR=3.90, 95% CI: 2.89-5.25, p=4.8x10-19, Fig 1b). These results were replicated in 153 FL patients from the Lyon registry: patients who achieved EFS12 had equivalent subsequent OS to the general French population (SMR=0.82, 95% CI: 0.39-1.72, p=0.60, Fig 1c), while patients who failed to achieve EFS12 had poor subsequent OS (SMR=4.16, 95% CI: 1.34-12.91, p=0.013, Fig 1d). In subset analysis of the MER, patients achieving EFS12 initially treated with IC (SMR=0.98, 95% CI: 0.63-1.54, p=0.93), RM (SMR=0.66, 95% CI: 0.31-1.38, p=0.27), or observation (SMR=0.73, 95% CI: 0.47-1.15, p=0.18) had equivalent OS to the population. In contrast, for patients not achieving EFS12, OS after event was inferior for those treated with IC (SMR=15.0, 95% CI: 10.22-22.05, p=2.0x10-43) or RM (SMR=4.96, 95% CI: 1.24-19.84, p=0.023), while trending towards inferior for those initially observed (SMR=1.55, 95% CI: 0.81-2.99, p=0.19). Summary: Events within the first 12 months of diagnosis are associated with poor OS in FL, especially in patients treated with IC, while patients achieving EFS12 have excellent subsequent survival, overall and in the main treatment subsets. Prognosis for FL patients should be recalibrated at 12 months from diagnosis. EFS12 will be useful in counseling and should be considered as an endpoint in studies of newly diagnosed FL. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Abstract To date, whole genome and exome sequencing studies of follicular lymphoma (FL) have primarily focused on identification of small site mutations that are recurrent in FL tumorigenesis or involved in tumor clonal evolution. A comprehensive genomic and transcriptomic survey of various mutation types including large structural variants (SVs) in FL cases with detailed clinical annotations and long-term follow-up has not been accomplished. To gain insight into genetic biomarkers that may predict clinical features, we performed exome and whole genome mate-pair sequencing of fresh frozen tumor and paired peripheral blood DNAs, and transcriptome sequencing of tumor RNAs, from 8 FL patients. The patients we selected were either below the median age of FL onset (n=7, median 54.5 yrs) or had a family history of lymphoma (n=1). These patients were clinically diverse, and included patients who had Grade 1 or 2 disease (n=4), classified as “indolent”; and patients with Grade 3a disease (n=2) or who subsequently had pathologic transformation (n=2), classified as “aggressive”. The coding regions of the genome (exome) were captured using Agilent SureSelect Target Capture Kit V2.0, and sequenced at 100-bp paired-end. The single nucleotide variants (SNVs) and small insertions and deletions (INDELs) were called using The Genome Analysis Toolkit (GATK), and the exon level copy number variants (CNVs) we identified using patternCNV. The whole-genome mate-pair libraries of both normal and tumor DNAs with 3kb insert sizes were sequenced paired end at 50-bp. The large SVs of CNVs, large INDELs, translocations, and inversions were identified using the SnowShoes-SV algorithm. The RNA sequencing libraries of 8 FL tumors were constructed using Illumina TruSeq protocol, and sequenced at 50-bp paired end. The RNA-Seq data were analyzed using TopHat and the fusion transcripts were identified using SnowShoes-FTD. Our analysis of SNVs and INDELs revealed mutations in previously reported genes including MLL2, CREBBP, TNFRSF14, and histone cluster genes (HIST1H2AM, HIST1H2BD). In addition, we identified novel recurrent mutations in cysteine-rich PAK1 inhibitor (CRIPAK) in 25% of the tumors. In a secondary analysis performed by Sanger sequencing or re-analysis of publically available RNA sequencing data, we identified CRIPAK mutations in 44% of FL (n=32) and 28% of DLBCL tumors (n=102). Bioinformatics analysis shows that the coding region of CRIPAK is highly enriched with the protein functional domain, post-SET, which is usually found in histone lysine methyltransferases (HMTase) genes including MLL2 and EZH2 that are known to be important in lymphomagenesis. Interestingly, CRIPAK is part of the same regulatory network consisted of previously identified lymphoma genes including MLL2, EZH2, CREBBP, and EP300, according to the shortest path algorithm by MetaCore (Philadelphia, Pennsylvania). Recurrent SVs identified in the FL tumors included the well-known IGH-BCL2 translocation, or t(14;18), in 6 out of 8 cases (75%) and the chr1q amplifications in 4 out of 8 (50%) tumors. Other non-recurrent large CNVs involving entire chromosomes or chromosome arms, as well as other inter- and intra-chromosomal structural variants were detected in individual tumors. In addition, we identified and validated 6 fusion transcripts from the transcriptome sequencing data in 3 out of 8 cases (38%). While our sample size is small, we found that SNVs and INDELs in MLL2, CREBBP, TNFRSF14, CRIPAK, and histone cluster genes, as well as t(14;18), did not distinguish indolent or aggressive tumors. However, all aggressive (4/4, 100%) and none of the indolent tumors had gains in chr1q; and the presence of RNA fusion transcripts were observed in aggressive tumors only (3/4, 75%). Additionally, we found that aggressive tumors had higher numbers of genes with point mutations (SNVs and short INDELs) (40 ± 7.6 vs. 26 ± 2.6; aggressive vs. indolent), higher numbers of genes impacted by copy number aberrations (1060 ± 263.7 vs. 233 ± 133.9), and higher numbers of large SVs (24 ± 10 vs. 6 ± 1.6). Taken together, our comprehensive analysis of 8 FL tumors reveals genetic diversity among newly diagnosed FL patients, identifies novel and recurrent mutations in CRIPAK, and finds that high tumor complexity and DNA instability may be indicators of aggressive disease. Disclosures No relevant conflicts of interest to declare.

Abstract Introduction T-cell prolymphocytic leukemia (T-PLL) is a rare mature T-Cell malignancy typically associated with aggressive clinical course. Leukemic T-cells demonstrate post-thymic T-cell phenotypes (Tdt-, CD1a-, CD5+, CD2+ and CD7+) and commonly are CD4+/CD8- T-cells, but co-expression of CD4+/CD8+ or CD8+/CD4- have also been observed. Rearrangement of chromosome 14 involving TCL1 locus is the cornerstone for T-PLL diagnosis which leads to overexpression of oncogene TCL1. As a binding partner for TCL1, AKT expression correlates with worse prognosis. Despite advances in identification of novel mutations, therapeutic option is limited with most patients having very short survival. Herein, we performed a detailed analysis of specific T-cell subsets affected in T-PLL and a comprehensive genomic analysis by whole exome sequencing (WES) and RNA sequencing. We also explored the preclinical efficacy of targeting AKT activation by AKT inhibitor MK2206 on leukemic T-cells isolated from T-PLL patients. Methods T-PLL leukemic cells were isolated from blood or marrow samples of T-PLL patients (n=9) and were tested for involved T-cell subsets by multicolor flow cytometric analysis. Leukemic T-cells were treated with escalating doses of MK2206 (0 to 10 µM) for about 80 hours and were assessed for their apoptosis levels using Annexin V flow cytometric analysis. Whole exome sequencing (WES) and RNA sequencing were conducted using genomic DNA and RNA isolated from purified leukemic T cells from T-PLL patients. Results Phenotypic analysis of T-cell subsets in T-PLL patients showed that leukemic T-cells in 4 untreated T-PLL patients are consistent with naïve T-cell phenotype (CD45RA+, CD45RO-, CCR7+). Leukemic T-cells in 3 of the untreated patients and in 2 of the treated patients have central memory T (CD45RA-, CD45RO+, CCR7+) and effector memory T phenotypes (CD45RA-, CD45RO+,CCR7-) respectively. MK2206 treatment was able to induce dose-dependent apoptosis on the isolated PBMC (containing > 90% leukemic T-cells) of T-PLL patients (n=4) (IC50: 5 µM). FISH analysis found a rearrangement of TCL1 locus on chromosome 14 in all T-PLL cases (n=9). Three cases have also been detected to have del (11q) involving ATM locus and one patient has both del(11q) and del(17p). Subsequent WES (n=7) and RNA sequencing (n=6) analysis revealed recently reported mutations in ATM (frame shift mutation and early stop mutation W579*) in 2 cases, JAK3 (M511I) in 2 cases and STAT5B (T628S and N642H) in 2 cases. Importantly, novel somatic mutations in gene IKZF1 (N159S), NTRK1 (R33W), AP2A2 (P514L), HDAC8 (I115R), RARB (G90W) and TNIP2 (K104Q) were detected by WES. Mutations in EML4 (L548W and F304S) and VAV3 (C282Y and splice site mutation) were also identified in 2 different T-PLL cases. RNA sequencing revealed several fusion transcripts resulting in early stop of several different genes including PTPRT, L3MBTL1, UCKL1 in one T-PLL case. Conclusion T-PLL leukemic T-cells are consistent with either naïve or central memory T-cell subsets in untreated patients. The AKT inhibitor MK-2206 was capable of inducing apoptosis and could be a potential therapeutic agent for T-PLL patients. In addition, we detected known mutations in ATM and JAK-STAT pathways. Novel mutations in genes involving DNA binding and chromatin remodeling (IKZF1, HDAC8) or kinase signal pathway (NTRK1, TNIP2, VAV3, EML4) were uncovered. These results suggest that further therapeutic approaches could be developed to target DNA binding factors or JAK-STAT or AKT-TCL1 signal pathway with an ultimate goal to improve survival of T-PLL patients. Disclosures Off Label Use: Off label use of MK2206: MK-2206 is an AKT inhibitor obtained from Selleck Chemicals and is used to treat leukemic cells in vitro to test the leukemic sensitivity to AKT inhibition. .

Abstract Abstract 140 Background: Peripheral T-cell lymphomas (PTCLs) have poor outcomes, and there is a lack of prognostic biomarkers and therapeutic targets to guide treatment. We recently proposed that the transcription factor, interferon regulatory factor-4 (IRF4, also called multiple myeloma oncogene-1 [MUM1]), might be oncogenic in PTCLs based on its expression in association with translocations between IRF4 and the T-cell receptor gene, TRA@. IRF4 is a therapeutic target in multiple myeloma, where high expression is a poor prognostic factor. In addition, at least two germline IRF4 single nucleotide polymorphisms (SNPs), rs12203592 and rs872071, are associated with IRF4 expression and disease risk and progression in various lymphoid neoplasms. However, the prognostic effects of IRF4/MUM1 expression and IRF4 SNPs in PTCLs are unknown. Methods: Forty seven newly diagnosed PTCL patients with available tissue were identified from the University of Iowa/Mayo Clinic Lymphoma SPORE Molecular Epidemiology Resource. There were 5 anaplastic large cell lymphomas, 14 cutaneous T-cell lymphomas (CTCLs), 6 cytotoxic T-cell lymphomas (cytTCLs: 4 extranodal NK/T-cell and 2 enteropathy type), and 22 PTCLs, not otherwise specified (NOS). Patients were diagnosed between September 2002 and February 2008 and systematically followed through March 2010 for overall survival (OS). Tumor cell IRF4/MUM1 expression was examined by immunohistochemistry on paraffin tissue sections (MUM1p clone; Dako). Positivity was defined as >30% of tumor cells with nuclear staining, as in previous studies. rs12203592 and rs872071 were genotyped in peripheral blood DNA. Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for both IRF4/MUM1 expression and SNPs with OS. Chi-squared tests were used to assess the relationship between IRF4/MUM1 expression and IRF4 SNPs. Results: The median age at diagnosis was 60 years (range, 24–88). At a median follow-up of 62 months (range, 29–89), 22 (47%) of the patients had died. Fifteen (32%) of the 47 T-cell patients had IRF4/MUM1 positive tumors. IRF4/MUM1 positivity was associated with poorer overall survival (HR=4.3; 95% CI: 1.8–10.2; p=0.0008). This association was seen across PTCL subtypes, including PTCL, NOS (HR= 6.5; 95% CI: 1.5–27.7; p=0.01), CTCL (HR=13.4; 95% CI: 1.2–150.1; p=0.03), and cytTCL (HR=5.8; CI: 0.5–65.9; p=0.15). The minor allele (T) in SNP rs12203592 was positively associated with IRF4/MUM1 positivity in a dominant model, with IRF4/MUM1 expression in 60% of patients with CT or TT genotypes compared to 19% of patients with CC genotype (p=0.01). Patients with the CT/TT genotype at rs12203592 also had inferior overall survival (HR=3.7; 95% CI: 1.4–9.5; p=0.007). The rs872071 SNP showed no significant association with either IRF4/MUM1 expression (p=0.38) or overall survival (p=0.71). Conclusions: This study is the first to demonstrate that IRF4/MUM1 expression is poor prognostic factor in PTCLs. This association was observed across PTCL subtypes, including the most common subtype, PTCL, NOS. IRF4/MUM1 expression and poor survival in our patients also were associated with the minor allele (T) in the IRF4 SNP rs12203592; these findings are consistent with previous in vitro data showing the major allele (C) represses IRF4 promoter activity. Interestingly, rs872071 was not associated with IRF4/MUM1 expression or prognosis, similar to findings in multiple myeloma. In contrast, rs872071 is a risk and prognostic factor in chronic lymphocytic leukemia and classical Hodgkin lymphoma, diseases in which IRF4/MUM1 expression has been associated with favorable prognosis. IRF4/MUM1 expression is a poor prognostic factor in PTCLs. Disclosures: No relevant conflicts of interest to declare.

One-third of peripheral T-cell lymphomas are “not otherwise specified” (PTCL-NOS), but they have been subdivided into 2 subgroups based on gene expression profiling. Amador and colleagues generated an immunohistochemical algorithm that parallels the molecular separation of PTCL-NOS and provides useful prognostic information.

AimsThe aims of this study were to review our 5‐year experience with clinical FISH testing for TP63 rearrangements using both TP63 break‐apart (BAP) and TBL1XR1/TP63 dual‐fusion (D‐FISH) probes to evaluate the frequency of TP63 rearrangements and the distribution of TBL1XR1 vs. alternate partner loci, and to assess whether both probe sets are necessary in all cases undergoing FISH testing.Methods and resultsA retrospective review of the Mayo Clinic cytogenetic database identified 470 patients evaluated by FISH testing for TP63 rearrangements in formalin‐fixed paraffin‐embedded (FFPE) tissue using both BAP and D‐FISH probes. Of these, 25 (5.3%) had TP63 rearrangements. All samples were being investigated for anaplastic large‐cell lymphoma or other T cell lymphoma subtypes. A TBL1XR1 partner was identified by D‐FISH in 12 (48%) of 25 cases. All cases positive by TBL1XR1/TP63 D‐FISH were also positive by TP63 BAP FISH.ConclusionThis is the largest series of TP63 rearrangements to date. The frequency of positive results among cases referred to a large reference laboratory for TP63 FISH testing was 5.3%. Approximately half of TP63 rearrangements have a TBL1XR1 partner. TP63 BAP FISH testing is sufficient for up‐front testing of FFPE tissue samples. However, because of the genomic proximity of the TP63 and TBL1XR1 loci, we recommend reflex TBL1XR1/TP63 D‐FISH testing in positive and equivocal cases.

AbstractBackgroundHuman pegivirus (HPgV) is a single-strand RNA virus belonging to the Flaviviridae. Although no definitive association between HPgV infection and disease has been identified, previous studies have suggested an association of HPgV viremia with risk of lymphomas.MethodsWe conducted a systematic review and meta-analysis, including 1 cohort study and 14 case-control studies, assessing the association of HPgV viremia with adult lymphomas. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model, overall and by geographic region and lymphoma subtype.ResultsThe overall OR for lymphoma was 2.85 (95% CI, 1.98–4.11), with statistically significantly elevated ORs observed in 8 of 15 studies. There was a small amount of heterogeneity among studies (I2 = 28.9%; Q = 18.27, P = .16), and the funnel plot provided no evidence for publication bias. The strongest association with lymphoma risk was observed for studies from Southern Europe (OR, 5.68 [95% CI, 1.98–16.3]), whereas weaker ORs (with 95% CIs) were observed for studies from North America (2.24 [1.76–2.85]), Northern Europe (2.90 [.45–18.7), and the Middle East (2.51 [.87–7.27]), but all of similar magnitude. Participants with HPgV viremia had statistically significantly increased risks (OR [95% CI]) for developing diffuse large B-cell (3.29 [1.63–6.62]), follicular (3.01 [1.95–4.63]), marginal zone (1.90 [1.13–3.18]), and T-cell (2.11 [1.17–3.89]) lymphomas, while the risk for Hodgkin lymphoma (3.53 [.48–25.9]) and chronic lymphocytic leukemia (1.45 [.45–4.66]) were increased but did not achieve statistical significance.ConclusionsThis meta-analysis supports a positive association of HPgV viremia with lymphoma risk, overall and for the major lymphoma subtypes.