Relationship between interferon regulatory factor 4 genetic polymorphisms, measures of sun sensitivity and risk for non-Hodgkin lymphoma
Sun exposure and sensitivity, including pigmentation, are associated with risk for non-Hodgkin lymphoma (NHL). One variant in the immune regulatory factor 4 (IRF4) gene (rs12203592) is associated with pigmentation, and a different IRF4 variant (rs12211228) is associated with NHL risk. We evaluated the independent roles of these IRF4 polymorphisms and sun sensitivity in mediating NHL risk and explored whether they are confounded or modified by each other. Genotyping of tag single nucleotide polymorphisms (SNPs) in the IRF4 gene was conducted in 990 NHL cases and 828 controls from a multi-center US study. Measures of sun sensitivity and exposure were ascertained from computer-assisted personal interviews. We used logistic regression to compute odds ratios (OR) and 95% confidence intervals (CI) for NHL in relation to sun exposures, sun exposures in relation to IRF4 genotypes, and NHL in relation to sun exposures. We further assessed the effects of sun exposures in relation to IRF4 genotypes. As previously reported, we found significant associations between IRF4 rs12211228 and NHL and between hair and eye color and NHL. The IRF4 rs12203592 polymorphism (CT/TT genotype) was statistically significantly associated with eye color and particularly with hair color (ORLight Blonde = 0.24, 95% CI = 0.11–0.50, overall Chi square p = 0.0002). Analysis of joint effects between eye and hair color with the IRF4 rs12203592 SNP did not reveal statistically significant p-interactions although NHL risk did decline with lighter hair color and presence of the variant IRF4 rs12203592 allele, compared to those without a variant allele and with black/brown hair color. Our data do not statistically support a joint effect between IRF4 and sun sensitivity in mediating risk for NHL. Further evaluation of joint effects in other and larger populations is warranted.