Association between tumor necrosis factor α-308 G/A polymorphism and bladder cancer risk: A meta-analysis

Previous studies have investigated the association between TNF-α -308 G/A polymorphism and bladder cancer risk in various populations. However, these findings remain inconclusive. Therefore, we performed a meta-analysis to explore the relationship between TNF-α -308 G/A polymorphism and bladder cancer risk. A literature search in PubMed was performed to select eligible studies regarding the association between TNF-α -308 G/A polymorphism and bladder cancer risk. The strength of risk under fixed- and random-effects models were estimated using the odds ratios (ORs) with 95% confidence intervals (CIs). We collected 7 case-control studies including 1153 cases and 1587 controls were included in the present meta-analysis. Compared with subjects carrying the G/G genotype of TNF-α -308 G/A polymorphism, those with the A/A and G/A genotypes had non-significant bladder cancer risks under the fixed effects model (OR=1.037) and the random effects model (OR=1.012). In the recessive model, subjects with the A/A genotype had an increased bladder cancer risk (OR=1.875) compared with those carrying the G/A and G/G genotypes of TNF-α -308 G/A polymorphism. The major finding of this meta-analysis suggests that TNF-α -308 G/A polymorphism is correlated with the risk of bladder cancer in Asian population under the recessive model. Further investigate of the joint effects of environmental risk factors and TNF-α -308 G/A polymorphism on bladder cancer risk should be considered.