Meta-analysis of transforming growth factor β receptor I 6A/9A gene polymorphism and breast cancer risk: the picture remains murky

AbstractBreast cancer is currently the second most common cancer worldwide and the most frequent malignant tumor among women. However, the exact contribution of various allelic alterations remains unclear. This meta-analysis was conducted to evaluate the association of the transforming growth factor β receptor I 6A/9A (TβR-I 6A/9A) gene polymorphism with breast cancer risk. Relevant studies were identified from PubMed and Cochrane Library on 1 October 2013, and eligible reports were recruited and synthesized. Eleven reports that included a total of 12 studies were recruited into this meta-analysis for the association of the TβR-I 6A/9A gene polymorphism and breast cancer risk. The results indicated that overall the TβR-I 6A allele was associated with breast cancer risk (OR = 1.33, 95% CI: 1.02–1.73, p = 0.04). However, the TβR-I 6A/6A and 9A/9A genotypes were not associated with an increased risk of developing breast cancer (6A/6A: OR = 1.71, 95% CI: 0.95–3.08, p = 0.07; 9A/9A: OR = 0.82, 95% CI: 0.66–1.0...