Fok1 polymorphism of vitamin D receptor gene contributes to breast cancer susceptibility: a meta-analysis

Several polymorphisms in the vitamin D receptor (VDR) gene have been reported to influence breast cancer risk. However, the published findings have been conflicting. We conducted a meta-analysis of 21 case-control studies with Fok1 (eight studies with 5,284 cases and 7,500 controls), Bsm1 (14 studies with 5,498 cases and 7,943 controls), Apa1 (four studies with 1,138 cases and 7,943 controls), Taq1 (10 studies with 4,459 cases and 5,485 controls) polymorphisms. The results showed Fok1 polymorphism was associated with an overall significantly increased risk of breast cancer (ff vs. FF: OR = 1.15, 95% CI = 1.03-1.28; the recessive model ff vs. Ff + FF: OR = 1.14, 95% CI = 1.03-1.26). In subgroup analysis, a significant association was evident between Fok1 polymorphism and breast cancer in European population (ff vs. FF: OR = 1.16, 95% CI = 1.04-1.30; the recessive model ff vs. Ff + FF: OR = 1.15, 95% CI = 1.04-1.28). There was no between-study heterogeneity in any of these analyses. No significant associations were observed between the Bsm1, Apa1 and Taq1 variants and breast cancer risk. So, the current meta-analysis shows that Fok1 may be a susceptibility biomarker for breast cancer especially in European population.