title: A meta-analysis of genome-wide association studies of follicular lymphoma.
abstract: BACKGROUND
  B-cell non-Hodgkin lymphoma represents a diverse group of hematological malignancies, of which follicular lymphoma (FL) is one of the most common subtypes. Family and epidemiological studies suggest an important genetic role in the etiology of FL. In recent genome-wide association studies (GWAS) of FL, several genetic susceptibility loci have been identified on chromosome 6p21.33 (rs6457327) and 6p21.32 (rs10484561, rs2647012) in the human leukocyte antigen class I and class II regions. To identify new genetic variants and further elucidate the genetic basis of FL, a meta-analysis was performed of the top 1000 SNPs associated with FL risk from two GWAS in the US, Denmark and Sweden (592 cases, 1541 controls), with independent validation in 107 cases and 681 controls.
  
  
  RESULTS
  rs9275517 and rs3117222 in the HLA class II region were validated and inversely associated with FL risk (rs9275517: OR = 0.63, 95% CI = 0.55-0.73, p = 4.03 × 10(-11); rs3117222: OR = 0.66, 95% CI = 0.57-0.77, p = 1.45 × 10(-7)). rs9275517, which is in high linkage disequilibrium with rs2647012 (r2 = 0.9), was no longer associated with FL after conditioning on rs2647012. The rs3117222 association was independent of established FL SNPs, but not of the HLA-DPB1*0301 allele. Using publicly available gene expression profiles with matching genotype information, we found that rs3117222 also was significantly correlated with increased HLA-DPB1 expression.
  
  
  CONCLUSIONS
  By performing a meta-analysis of two GWAS of FL, we further validated the relevance of HLA-DPB1*0301 as a protective allele in the pathogenesis of FL. Moreover, the protective rs3117222 A allele correlated with increased levels of HLA-DPB1, suggesting a possible disease mechanism involving HLA-DPB1 expression regulation. Our results add further support to the major role of HLA genetic variation in the pathogenesis of FL.
authors.affiliation: School of Public Health, Division of Environmental Health Sciences, University of California, Berkeley, 94720, USA. chrisfs@berkeley.edu
authors.forename: Christine F
authors.initials: CF
authors.lastname: Skibola
authors.forename: Lucia
authors.initials: L
authors.lastname: Conde
authors.forename: Jia-Nee
authors.initials: JN
authors.lastname: Foo
authors.forename: Jacques
authors.initials: J
authors.lastname: Riby
authors.forename: Keith
authors.initials: K
authors.lastname: Humphreys
authors.forename: Fenna C M
authors.initials: FC
authors.lastname: Sillé
authors.forename: Hatef
authors.initials: H
authors.lastname: Darabi
authors.forename: Sylvia
authors.initials: S
authors.lastname: Sanchez
authors.forename: Henrik
authors.initials: H
authors.lastname: Hjalgrim
authors.forename: Jianjun
authors.initials: J
authors.lastname: Liu
authors.forename: Paige M
authors.initials: PM
authors.lastname: Bracci
authors.forename: Karin E
authors.initials: KE
authors.lastname: Smedby
mesh_terms: D000483:Alleles; D016022:Case-Control Studies; D005260:Female; D005786:Gene Expression Regulation; D056426:Genetic Loci; D020022:Genetic Predisposition to Disease; D055106:Genome-Wide Association Study; D059868:HLA-DP beta-Chains / Q000235:genetics* / Q000276:immunology; D006801:Humans; D015810:Linkage Disequilibrium; D008224:Lymphoma, Follicular / Q000235:genetics* / Q000276:immunology; D008297:Male; D020641:Polymorphism, Single Nucleotide; D012306:Risk
chemical_list: D059868:HLA-DP beta-Chains; C071170:HLA-DPB1 antigen