Abstract Background. DLBCL is the most common non-Hodgkin lymphoma (NHL) subtype in western countries and is known to be clinically heterogeneous. Gene expression profiling has identified two major, biologically distinctive DLBCL subtypes on the basis of their cell-of-origin (COO): the germinal center B-cell (GCB) - characterized by BCL2 rearrangement and C-REL amplification, and activated B-cell (ABC) - characterized by constitutive activation of the NF-kB pathway. Recently, the InterLymph Subtypes Project identified medical history, lifestyle, and family history risk factors for DLBCL using a large pooled analysis of case-control studies. In this study we evaluated these same risk factors for etiologic heterogeneity as defined by DLBCL COO. Methods. For this analysis we used a clinic-based study of newly diagnosed NHL cases and frequency matched controls, enrolled from 2002-2012, with 474 DLBCL cases and 2203 controls. COO was determined clinically using the Hans algorithm, which is based on immunohistochemistry markers using formalin-fixed, paraffin-embedded tumor tissue. Amongst DLBCL cases 107 were ABC, 207 were GCB, and 160 were missing subtype (tissue unavailable). Risk factor data, including body mass index (BMI), smoking, alcohol use, any allergy, asthma, blood transfusion, diabetes, rheumatoid arthritis, sun exposure, lived on a farm and family history of hematologic malignancy, were collected from self-administered questionnaires. Polytomous logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals for ABC and GCB subtypes, adjusted for age and sex. Results. The mean age of cases was 60.4 years with 53% male; the mean age of controls was 61.6 years and 53% male. We identified a strong positive association for BMI with risk of ABC but not GBC DLBCL (p-heterogeneity 0.025). Compared to BMI 18.5-24.9 kg/m2, those with a BMI of 25.0-29.9 (OR = 1.65; 0.93-2.93) or 30+ (OR = 2.61; 1.48-4.62) were at increased risk of ABC DLBCL. There was no association for a BMI of 25.0-29.9 (OR = 0.91; 0.63-1.31) or 30+ (OR = 1.21; 0.83-1.76) with GCB DLBCL. There was no evidence of significant heterogeneity between ABC and GCB DLBCL for the other risk factors that we evaluated. Further adjustment of the BMI association for educational level, smoking, and alcohol only slightly attenuated these findings. Conclusions. We observed a strong positive association of BMI with ABC but not GCB DLBCL. In contrast, other evaluated risk factors showed no heterogeneity by COO. While BMI has not been clearly associated with NHL overall, there has been evidence for an association with DLBCL. The etiologic heterogeneity we observed for ABC DLBCL is notable as BMI is also a strong risk factor for multiple myeloma, another post-germinal center B-cell malignancy. While requiring replication, our findings suggest BMI may influence B-cell neoplasia through effect on post-germinal center pathways. Citation Format: Matthew K. Breitenstein, Megan M. O’Byrne, Andrew L. Feldman, Carrie A. Thompson, William R. Macon, Grzegorz S. Nowakowski, Stephen M. Ansell, Susan L. Slager, Thomas M. Habermann, James R. Cerhan. Body mass index shows etiologic heterogeneity for risk of diffuse large B-cell lymphoma (DLBCL) subtype defined by cell-of-origin. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1762.
Integrated mate-pair and RNA sequencing identifies novel, targetable gene fusions in peripheral T-cell lymphoma
Abstract Peripheral T-cell lymphomas (PTCLs) represent a heterogeneous group of T-cell malignancies that generally demonstrate aggressive clinical behavior, often are refractory to standard therapy, and remain significantly understudied. The most common World Health Organization subtype is PTCL, not otherwise specified (NOS), essentially a “wastebasket” category because of inadequate understanding to assign cases to a more specific diagnostic entity. Identification of novel fusion genes has contributed significantly to improving the classification, biologic understanding, and therapeutic targeting of PTCLs. Here, we integrated mate-pair DNA and RNA next-generation sequencing to identify chromosomal rearrangements encoding expressed fusion transcripts in PTCL, NOS. Two of 11 cases had novel fusions involving VAV1, encoding a truncated form of the VAV1 guanine nucleotide exchange factor important in T-cell receptor signaling. Fluorescence in situ hybridization studies identified VAV1 rearrangements in 10 of 148 PTCLs (7%). These were observed exclusively in PTCL, NOS (11%) and anaplastic large cell lymphoma (11%). In vitro, ectopic expression of a VAV1 fusion promoted cell growth and migration in a RAC1-dependent manner. This growth was inhibited by azathioprine, a clinically available RAC1 inhibitor. We also identified novel kinase gene fusions, ITK-FER and IKZF2-ERBB4, as candidate therapeutic targets that show similarities to known recurrent oncogenic ITK-SYK fusions and ERBB4 transcript variants in PTCLs, respectively. Additional novel and potentially clinically relevant fusions also were discovered. Together, these findings identify VAV1 fusions as recurrent and targetable events in PTCLs and highlight the potential for clinical sequencing to guide individualized therapy approaches for this group of aggressive malignancies.
Abstract B143: Pharmacogenomic of refractory response to R-CHOP therapy in diffuse large B-cell lymphoma (DLBCL) patients
Abstract Background: Rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) therapy is standard of care for patients with newly diagnosed DLBCL. A majority of patients respond to R-CHOP, however ∼9% will have primary refractory disease and outcomes in these patients are extremely poor. While there is some knowledge of the pharmacogenomic (PGx) determinants of individual agents within R-CHOP, little is known about the PGx determinants of combination therapy. Our study aims to elucidate germline PGx determinants of drug bioavailability and undesirable side chain reactions in DLBCL patients treated with R-CHOP having potential to influence refractory disease. Methods: Newly diagnosed, DLBCL patients treated with R-CHOP between 2002 and 2012 with germline DNA and genotyping data were selected from the Molecular Epidemiology Resource within the Iowa/Mayo Lymphoma SPORE. Refractory disease was defined as either i) a best response of stable or progressive disease or ii) progressive disease by the end of the planned number of cycles of R-CHOP. PGx candidates within known pharmacokinetics and pharmacodynamics (PD) pathways for 11 genes (1,040 single nucleotide polymorphisms (SNPs)) were selected for study (CPT 2012;92(4):414-7). Odds ratios (ORs) and 95% confidence intervals (CI) were used to estimate the association of SNPs with refractory disease, controlling for age, gender, and age-adjusted International Prognostic Index. Results: The median age at diagnosis of 424 of DLBCL patients treated with R-CHOP was 62 years (range 18-92); 45.7% were female; and 58.4% had Ann Arbor Stage III-IV. By the end of initial therapy 40 patients had primary refractory disease. Of the 1,040 SNPs evaluated, 120 (12%) were significantly associated with refractory disease at the 5% significance threshold suggesting novel associations with drug metabolism. The top SNP from each PGx candidate gene are shown in Table, with ALDH5A1 and CYP2B6 showing the most significant associations. Conclusions: While needing replication, we identified associations within two PGx candidate genes that are potentially functionally related to cyclophosphamide PD: alleles within CYP2B6 may have relevance in R-CHOP outcomes due to potential competition with other drug metabolizing enzymes shared with prednisone and vincristine biotransformation in the liver, and alleles withinALDH5A1 may impact a deactivating side chain reaction in B lymphocytes. Table: R-CHOP PGx candidates with known side chain reactionsPGx candidaten SNPsTop SNPChrOR* (95% CI)P-valueMAFABCB1365rs3480093571.86 (1.14 – 3.04)1.32E-020.29ADH1A32rs122996841.66 (0.60 - 4.53)3.27E-010.038ALDH3A116rs2228100171.26 (0.71 - 2.22)4.28E-010.24ALDH5A1192rs946103466.30 (2.43 - 16.4)1.55E-040.030CBR110rs2835266212.10 (0.90 - 4.89)8.76E-020.052CBR356rs45527331212.12 (0.91 - 4.98)8.29E-020.050CYP2B6107rs1038376192.38 (1.44 - 3.94)7.74E-040.27CYP3A421rs2898858372.32 (0.80 - 6.78)1.23E-010.028CYP3A531rs778032871.69 (0.68 - 4.16)2.57E-010.054SLC22A16193rs11217403561.80 (1.06 - 3.03)2.78E-020.21SOD116rs1041740211.35 (0.83 - 2.19)2.26E-010.32Chr=chromosome, MAF=minor allele frequency, *Adjusted for age, sex, and age-adjusted International Prognostic Index Citation Format: Matthew K. Breitenstein, Susan L. Slager, Anne J. Novak, Matthew J. Maurer, Carrie A. Thompson, Umar Farooq, Brian K. Link, Thomas M. Habermann, Curtis L. Olswold, Andrew L. Feldman, Grzegorz S. Nowakowski, Stephen M. Ansell, Thomas E. Witzig, Richard M. Weinshilboum, Liewei Wang, James R. Cerhan. Pharmacogenomic of refractory response to R-CHOP therapy in diffuse large B-cell lymphoma (DLBCL) patients. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B143.
UCH-L1 is induced in germinal center B cells and identifies patients with aggressive germinal center diffuse large B-cell lymphoma
Key Points The neuronal marker UCH-L1 is induced in, and specifically augments the oncogene-induced transformation of, GCB cells. High levels of UCHL1 identify patients with GC DLBCL with an increased risk for poor outcomes.
Personalized risk prediction for event‐free survival at 24 months in patients with diffuse large B‐cell lymphoma