Association between TGFBR1 polymorphisms and cancer risk: a meta-analysis of 35 case-control studies.

BACKGROUND

Numerous epidemiological studies have evaluated the association between TGFBR1 polymorphisms and the risk of cancer, however, the results remain inconclusive. To derive a more precise estimation of the relation, we conducted a comprehensive meta-analysis of all available case-control studies relating the TGFBR1*6A and IVS7+24G>A polymorphisms of the TGFBR1 gene to the risk of cancer.

METHODS

Eligible studies were identified by search of electronic databases. Overall and subgroup analyses were performed. Odds ratio (OR) and 95% confidence interval (CI) were applied to assess the associations between TGFBR1*6A and IVS7+24G>A polymorphisms and cancer risk.

RESULTS

A total of 35 studies were identified, 32 with 19,767 cases and 18,516 controls for TGFBR16A polymorphism and 12 with 4,195 cases and 4,383 controls for IVS7+24G>A polymorphism. For TGFBR16A, significantly elevated cancer risk was found in all genetic models (dominant OR = 1.11, 95% CI = 1.041.18; recessive: OR = 1.36, 95% CI = 1.111.66; additive: OR = 1.13, 95% CI = 1.051.20). In subgroup analysis based on cancer type, increased cancer risk was found in ovarian and breast cancer. For IVS7+24G>A, significant correlation with overall cancer risk (dominant: OR = 1.39, 95% CI = 1.151.67; recessive: OR = 2.23, 95% CI = 1.263.92; additive: OR = 1.43, 95% CI = 1.141.80) was found, especially in Asian population. In the subgroup analysis stratified by cancer type, significant association was found in breast and colorectal cancer.

CONCLUSIONS

Our investigations demonstrate that TGFBR1*6A and IVS7+24G>A polymorphisms of TGFBR1 are associated with the susceptibility of cancer, and further functional research should be performed to explain the inconsistent results in different ethnicities and cancer types.