Transforming growth factor-β1 polymorphisms and breast cancer risk: a meta-analysis based on 27 case–control studies

The association between transforming growth factor-β1 (TGF-β1) gene polymorphisms and breast cancer risk has been widely reported, but results were somewhat controversial and underpowered. To derive a more precise estimation of the relationship between TGF-β1 polymorphisms and breast cancer risk, we conducted a meta-analysis of all available case–control studies relating the T869C and/or C-509T polymorphisms of the TGF-β1 gene to the risk of developing breast cancer. Eligible articles were identified by search of databases including MEDLINE, PubMed, Web of Science, EMBASE, and Chinese Biomedical Literature database (CBM) for the period up to March 2010. Finally, a total of 17 articles involving 27 case–control studies were identified, 25 with 20,022 cases and 24,423 controls for T869C polymorphism and eight with 10,633 cases and 13,648 controls for C-509T polymorphism. The pooled ORs were performed for the allele contrasts, additive genetic model, dominant genetic model and recessive genetic model, respectively. Subgroup analysis was also performed by ethnicity for T869C polymorphism. With respect to T869C polymorphism, no association was found in overall analysis (C vs. T: OR = 1.033, 95% CI = 0.996–1.072). In the subgroup analysis by ethnicity, significantly increased risk was found in Caucasian population (C vs. T: OR = 1.051, 95% CI = 1.018–1.085; CC vs. TT + TC: OR = 1.083, 95% CI = 1.019–1.151), but not in Asian population (C vs. T: OR = 1.054, 95% CI = 0.983–1.130). With respect to C-509T polymorphism, no significant association with breast cancer risk was demonstrated in overall analysis (T vs. C: OR = 0.986, 95% CI = 0.936–1.039). It can be concluded that potentially functional TGF-Β1 T869C polymorphism may play a low penetrance role in breast cancer susceptibility in an ethnicity-specific manner.