Ennas, Maria Grazia

AbstractEpidemiologic studies show an increased risk of non‐Hodgkin lymphoma (NHL) in patients with autoimmune disease (AD), due to a combination of shared environmental factors and/or genetic factors, or a causative cascade: chronic inflammation/antigen‐stimulation in one disease leads to another. Here we assess shared genetic risk in genome‐wide‐association‐studies (GWAS).Secondary analysis of GWAS of NHL subtypes (chronic lymphocytic leukemia, diffuse large B‐cell lymphoma, follicular lymphoma, and marginal zone lymphoma) and ADs (rheumatoid arthritis, systemic lupus erythematosus, and multiple sclerosis). Shared genetic risk was assessed by (a) description of regional genetic of overlap, (b) polygenic risk score (PRS), (c)"diseasome", (d)meta‐analysis.Descriptive analysis revealed few shared genetic factors between each AD and each NHL subtype. The PRS of ADs were not increased in NHL patients (nor vice versa). In the diseasome, NHLs shared more genetic etiology with ADs than solid cancers (p = .0041). A meta‐analysis (combing AD with NHL) implicated genes of apoptosis and telomere length.This GWAS‐based analysis four NHL subtypes and three ADs revealed few weakly‐associated shared loci, explaining little total risk. This suggests common genetic variation, as assessed by GWAS in these sample sizes, may not be the primary explanation for the link between these ADs and NHLs.

Abstract A growing number of loci within the human leukocyte antigen (HLA) region have been implicated in non-Hodgkin lymphoma (NHL) etiology. Here, we test a complementary hypothesis of “heterozygote advantage” regarding the role of HLA and NHL, whereby HLA diversity is beneficial and homozygous HLA loci are associated with increased disease risk. HLA alleles at class I and II loci were imputed from genome-wide association studies (GWAS) using SNP2HLA for 3,617 diffuse large B-cell lymphomas (DLBCL), 2,686 follicular lymphomas (FL), 2,878 chronic lymphocytic leukemia/small lymphocytic lymphomas (CLL/SLL), 741 marginal zone lymphomas (MZL), and 8,753 controls of European descent. Both DLBCL and MZL risk were elevated with homozygosity at class I HLA-B and -C loci (OR DLBCL = 1.31, 95% CI = 1.06–1.60; OR MZL = 1.45, 95% CI = 1.12–1.89) and class II HLA-DRB1 locus (OR DLBCL = 2.10, 95% CI = 1.24–3.55; OR MZL = 2.10, 95% CI = 0.99–4.45). Increased FL risk was observed with the overall increase in number of homozygous HLA class II loci (P trend < 0.0001, FDR = 0.0005). These results support a role for HLA zygosity in NHL etiology and suggests that distinct immune pathways may underly the etiology of the different NHL subtypes. Significance: HLA gene diversity reduces risk for non-Hodgkin lymphoma. Cancer Res; 78(14); 4086–96. ©2018 AACR.

Abstract Marginal zone lymphomas (MZL) are a group of indolent non-Hodgkin's B-cell lymphomas (NHL) comprising extranodal MZL of mucosa-associated lymphoid tissue (MALT) type, splenic MZL and nodal MZL. MZL comprises 7-12% of adult NHLs. The genetic etiology of MZL is poorly understood. To better understand the genetic risk factors for MZL, we conducted the first genome-wide association study (GWAS) of this lymphoid malignancy. The GWAS included 824 MZL cases and 6,220 controls of European ancestry from 22 studies of NHL. Genotyping was carried out at the Cancer Genomics Research Laboratory (CGR) of NCI using Illumina Human OmniExpress arrays. Standard genotyping quality controls were performed. Imputation of common SNPs was performed using IMPUTE2 software and 1000 Genomes Project release version 3 data. Association testing was subsequently performed using SNPTEST, assuming a log-additive genetic model adjusting for age, gender and three significant eigenvectors. We identified one locus at 6p21.32 within the HLA class II region that attained genome-wide significance (P<5x10-8). When a small number of additional cases (n=58) and controls (n=66) genotyped using Taqman assays were included, rs9461741 (BTNL2) was associated with an increased risk of MZL (per-allele odds ratio = 2.38, 95% confidence interval: 1.74-3.24; P=4.32x10-8). Other SNPs at the 6p21.32 locus were also highly associated with MZL, suggesting that this is unlikely to be a chance finding. Promising signals yet to be confirmed were also observed on chromosomes 3 and 14. The BTNL2 protein has extracellular immunoglobulin domains and is expressed in multiple tissues including various immune organs and the gut and it inhibits T-cell activation. Genetic variability at BTNL2 has been associated with inflammatory and infectious phenotypes, highlighting the importance of this locus for immune diseases. In conclusion, findings from this GWAS identify the HLA class II region as an important susceptibility locus for MZL. Citation Format: Joseph Vijai, Zhaoming Wang, Sonja I. Berndt, Susan L. Slager, James R. Cerhan, Christine Skibola, Sophia S. Wang, Angela R. Brooks-Wilson, Silvia de Sanjose, Paige M. Bracci, Mads Melbye, Bengt Glimelius, Rebecca D. Jackson, Wendy Cozen, Nikolaus Becker, Lauren R. Teras, John J. Spinelli, Jenny Turner, Qing Lan, Mark P. Purdue, Kimberly A. Bertrand, Kenneth Offit, Paolo Vineis, Brian K. Link, Graham G. Giles, Anne Zelenuich-Jacquotte, Alain Monnereau, Maria Grazia Ennas, Demetrius Albanes, Laurie Burdett, Nathaniel Rothman, Stephen J. Chanock, Alexandra Nieters, On behalf of the NHL GWAS Consortium. A genome-wide association study suggests evidence of variants at 6p21.32 associated with marginal zone lymphoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5071. doi:10.1158/1538-7445.AM2014-5071