Quantitative assessment of the influence of tumor necrosis factor alpha polymorphism with gastritis and gastric cancer risk

Tumor necrosis factor alpha (TNFA) is an important molecule in inflammatory, infectious, and tumoral processes. Inflammation is one of the early phases in the development of gastric cancer (GC). Therefore, several studies have examined the association of polymorphism in TNFA with gastritis and GC risk. A functional polymorphism, -308G>A (rs1800629), which is located in the promoter of TNFA gene, has been suggested to alter the production of TNF-α and influence cancer risk. To date, a number of studies have been carried out to investigate the relationship between the polymorphism and gastritis or GC susceptibility, but the results were conflicting. To investigate this inconsistency, we performed a meta-analysis of 36 studies for TNFA -308G>A polymorphism to evaluate the effect of TNFA on genetic susceptibility for gastritis and GC. An overall random-effects per-allele odds ratio of 1.16 (95 % confidence interval 1.04–1.29, P = 0.008) was found for the polymorphism. Significant results were also observed using dominant or recessive genetic models. In the subgroup analyses by ethnicity, significant results were found in Caucasians, whereas no significant associations were found among East Asians and other ethnic populations. No associations between the polymorphism and gastritis were observed. In addition, our data indicate that TNFA is involved in GC susceptibility and confers its effect primarily in diffuse type of tumors. Besides, -308G>A polymorphism was found to be significantly associated with both cardiac and noncardiac tumors. This meta-analysis demonstrated that the TNFA -308G>A polymorphism is a risk factor for developing GC, but the associations vary in different ethnic populations.