FokI polymorphism in vitamin D receptor gene and risk of breast cancer among Caucasian women.

Vitamin D plays a central role in cellular proliferation, apoptosis induction, and tumor growth suppression. The vitamin D receptor (VDR) is a crucial mediator for the cellular effects of vitamin D. A series of epidemiological studies have examined the association between the VDR FokI polymorphism and breast cancer risk, but the findings remain inconclusive. Fifteen eligible case-control studies involving 15,681 cancer cases and 20,632 control subjects were identified through searching PubMed, Embase, and Web of Science. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the association. Heterogeneity across studies was examined with the chi-square-based Q test and the I (2) index. Begg's and Egger's test were also performed to determine publication bias. All statistical data were analyzed by STATA software. The combined estimates did not show significant risks correlated with the FokI polymorphism. However, we found an increased risk in the subgroup analysis by source of control (OR = 1.11, 95% CI = 1.01-1.22; heterogeneity test: P = 0.116, I(2) = 0.0% for ff vs FF; OR = 1.10, 95% CI = 1.01-1.21; heterogeneity test: P = 0.832, I(2) = 0.0% for ff vs Ff + FF). This meta-analysis suggests that the presence of FokI polymorphism may contribute to the risk of breast cancer in Caucasians.