Heterozygosity for TGF β1 -509C/T Polymorphism is associated with risk for breast cancer in South Indian population

Association of TGF-β1 Polymorphisms with Breast Cancer Risk: A Meta-Analysis of Case-Control Studies †

Reports on the association of TGF-β1 polymorphisms with breast cancer (BC) have been conflicting, inconsistent, inconclusive, and controversial. PubMed, EMBASE, and Google Scholar were used to identify studies on TGF-β1 polymorphisms and BC risk. Data were extracted independently, and of the initial 3043 studies, 39 case-control studies were eligible for inclusion in the meta-analysis. Information from these studies was extracted, and the overall associations of three TGF-β1 polymorphisms (TGF-β1 29>T/C, TGF-β1-509 C/T, and TGF-β1*6A) with BC risk were analyzed using overall allele, homozygous, heterozygous, recessive, and dominant models. None of the three TGF-β1 polymorphisms studied had a significant influence on the development of BC. However, stratified analysis revealed a positive correlation between the TGF-β1 29T>C polymorphism and BC risk according to a heterozygous model of the Asian population (odds ratio (OR) = 1.115, 95% confidence interval (CI) = 1.006–1.237, p = 0.039). Interestingly, this polymorphism was associated with lower odds of BC according to a heterozygous model of the Middle Eastern population (OR = 0.602, 95% CI = 0.375–0.966, p = 0.035). Thus, our analysis of large datasets indicates that the TGF-β1 29T>C polymorphism is significantly associated with BC risk in the Asian population. In contrast, the TGF-β1*6A and TGF-β1-509 C/T polymorphisms failed to show an association with BC.

Association of TGF-β1 -509C/T polymorphisms with breast cancer risk: evidence from an updated meta-analysis

Epidemiological studies have evaluated the association between transforming growth factor-β1 (TGF-β1) -509C/T polymorphisms and breast cancer risk. However, the results remain conflicting rather than conclusive. The aim of this study was to comprehensively clarify the association between TGF-β1 -509C/T polymorphisms and breast cancer risk. All relevant studies were searched in the electronic databases. The potential sources of heterogeneity were detected with the chi-square-based Q test. The strength of associations between TGF-β1 -509C/T polymorphisms and breast cancer risk was measured by odds ratio (OR) and 95 % confidence intervals (CI). Publication bias was tested by Begg's test and Egger's test. A total of 10 studies including 10,913 cases and 14,187 controls were included in the meta-analysis. Overall, there was no evidence of significant association of TGF-β1 -509C/T polymorphisms with breast cancer risk (TT vs. CC [OR = 0.97, 95 % CI = 0.83-1.14]; CT vs. CC [OR = 1.05, 95 % CI = 0.90-1.22]; TT + CT vs. CC [OR = 0.99, 95 % CI = 0.91-1.08]; T allele vs. C allele [OR = 0.99, 95 % CI = 0.93-1.06]). Similar results were also found in the subgroup analyses by ethnicity and source of control. When stratified by estrogen receptor (ER) status, TT genotype and T allele were associated with a decreased ER-positive breast cancer risk (OR = 0.66, 95 % CI = 0.49-0.90 and OR = 0.85, 95 % CI = 0.75-0.96, respectively). The present meta-analysis results suggest that TGF-β1 -509C/T variants may not contribute to the risk of breast cancer overall. However, T allele may be a potential protective factor for developing ER-positive breast cancer. Well-designed studies with larger sample size were required to verify our findings further.