Association of a progesterone receptor gene +331 G/A polymorphism with breast cancer risk: a meta-analysis

Published studies on the association between the progesterone receptor gene +331 G/A polymorphism and breast cancer risk are inconclusive, and meta-analysis is required to verify the association. Six studies, including a total of 6,849 cases and 6,589 controls, were subjected to meta-analysis. When all eligible subjects were pooled for meta-analysis, the AG + AA variant genotype was not associated with a significantly elevated breast cancer risk [odds ratio (OR) = 1.11; 95% confidence interval (95%CI) = 0.99-1.24; P = 0.071]. However, subgroup analysis revealed that the AG + AA variant genotype was associated with an increased risk of breast cancer in American (OR = 1.32; 95%CI = 1.10-1.58; P = 0.003), but not in European or Australian. We could carefully suggest that the progesterone receptor promoter +331 G/A variant polymorphism might increase breast cancer risk, and this effect appeared to be more prominent in Americans than in Europeans and Australians.