TaqI polymorphism of VDR gene contributes to breast cancer risk.

Previous studies on the association of Vitamin D receptor (VDR) TaqI gene polymorphism with breast carcinogenesis have yielded inconsistent and inconclusive findings. The current meta-analysis was performed to provide a more precise assessment on the role of VDR TaqI polymorphism in breast cancer risk. 20 eligible case-control studies involving 9,055 cases and 10,516 controls were identified after a comprehensive literature search of the PubMed, Embase, Web of Science, and Wanfang databases. The pooled odds ratio (OR) with corresponding 95% confidence interval (95% CI) was calculated. Stratified analyses by ethnicity and study quality were conducted for further estimation. All statistical analyses were conducted by use of STATA (STATA Corporation, College Station, TX, Version 11.0). The overall ORs showed that the variant t allele and tt genotype were related to an increased risk of breast cancer (OR(t vs. T) = 1.05, 95% CI 1.01-1.10, P(OR) = 0.025; OR(tt vs. TT) = 1.12, 95% CI 1.03-1.23, P(OR) = 0.011; OR(tt vs. Tt + TT) = 1.10, 95% CI 1.01-1.20, P(OR) = 0.023). Stratified analyses of studies in Caucasians and with high-quality further confirmed the results. However, no significant relationship was observed among Asians. This meta-analysis suggests that the VDR TaqI polymorphism confers risk effect on the breast cancer development, particularly in Caucasians.