Variants in , and in vitamin D pathway genes are associated with breast cancer risk: a large-scale analysis of 14 GWASs in the DRIVE study.

Vitamin D has a potential anticarcinogenic role, possibly through regulation of cell proliferation and differentiation, stimulation of apoptosis, immune modulation and regulation of estrogen receptor levels. Because breast cancer (BC) risk varies among individuals exposed to similar risk factors, we hypothesize that genetic variants in the vitamin D pathway genes are associated with BC risk. To test this hypothesis, we performed a larger meta-analysis using 14 published GWAS datasets in the Discovery, Biology, and Risk of Inherited Variants in Breast Cancer (DRIVE) Study. We assessed associations between 2,994 (237 genotyped in the DRIVE study and 2,757 imputed from the 1000 Genomes Project) single nucleotide polymorphisms (SNPs) in 33 vitamin D pathway genes and BC risk. In unconditional logistic regression analysis, we found 11 noteworthy SNPs to be associated with BC risk after multiple comparison correction by the Bayesian false-discovery probability method (<0.80). In stepwise logistic regression analysis, with adjustment for age, principal components and previously published SNPs in the same study populations, we identified three independent SNPs ( rs1047920 C>T, rs11826 C>T and rs3914238 C>T) to be associated with BC risk ( = 0.0014, 0.0020 and 0.0022, respectively). Additional expression quantitative trait loci analysis revealed that the rs73276407 A allele, in a high LD with the rs1047920 T allele, was associated with decreased mRNA expression levels, while the rs11826 T allele was significantly associated with elevated mRNA expression levels. Once replicated by other investigators and additional mechanistic studies, these genetic variants may serve as new biomarkers for susceptibility to BC.