Association between Tumor necrosis factor-alpha gene polymorphisms and prostate cancer risk: a meta-analysis

Background: Tumor necrosis factor-alpha (TNF-alpha) is an important inflammatory cytokine that may play a role in controlling the progression of prostate cancer. Two common polymorphisms in the TNF-alpha gene, -308G/A and -238C/T, have been suggested to alter the risk for prostate cancer, but the results have been inconclusive so far. In order to obtain a better understanding of the effects of these two polymorphisms on prostate cancer risk, all available studies were considered in a meta-analysis. Methods: We conducted a comprehensive literature search in the Cochrane Library, PubMed, EMBASE, Chinese Biomedical Literature database (CBM), and the China National Knowledge Infrastructure (CNKI). The associations were evaluated by calculating the pooled odds ratio (OR) with 95% confidence interval (95% CI). Results: In this meta-analysis, we included 14 studies with 5,757 patients and 6,137 control subjects for the TNF-alpha-308G/A polymorphism and 1,967 patients and 2,004 control subjects for the TNF-alpha-238C/T polymorphism. A significantly increased prostate cancer risk was found to be associated with the TNF-alpha-308C/T polymorphism in studies with healthy volunteers (AA + AG vs. GG: OR = 1.531, 95% CI = 1.093-2.145; P = 0.013; AG vs. GG: OR = 1.477, 95% CI = 1.047-2.085; P = 0.026). No significant association was found between the TNF-alpha-238G/A polymorphism and prostate cancer risk in the overall or subgroup analyses. There was no risk of publication bias in this meta-analysis. Conclusions: Our results suggest that while the TNF-alpha-238G/A polymorphism may not be associated with prostate cancer the TNF-alpha-308C/T polymorphism may significantly contribute to prostate cancer susceptibility in healthy volunteers.