A meta-analysis of tumor necrosis factor-a-308 G>A polymorphism in gastric cancer

Background: Gastric cancer (GC) is the common cause of cancer-related deaths worldwide and inflammation represents the early phases in the GC. Objective: To review the tumor necrosis factor (TNF)-a-308 G>A (GG, GA, and AA) in GC by meta-analysis studies for any differences in TNF-alpha-308 G>A gene polymorphisms. Methods: Case-control studies published from 2003 to 2017 were identified by searching PubMed, EMASE, and the Internet with the English language. The analysis published on TNF-alpha-308 G>A polymorphism was analyzed and a limited number of articles were included in the present study. TNF-alpha-308 G>A from 4,157 patients and 5,185 healthy controls was evaluated. Studies were evaluated using Cochrane Q-test and publication bias was evaluated by constructing funnel plots. Results: Overall, TNF-alpha-308 GA genotype showed significant association [P < 0.0001, odds ratio (OR), 95% confidence interval (CI) = 0.82 (0.74-0.91)]. However, meta-analysis of TNF-alpha-308 genotypes (GG, GA, AA, and GA + AA) between GC patients and controls showed nonsignificant association with GC [P > 0.05, recessive model: OR = 1.38, 95% CI: 1.15-1.66; dominant model: OR = 1.23, 95% CI: 1.09-1.39; (G/A) vs. (G/G): OR = 1.15, 95% CI: 1.02-1.28; (A/A) vs. (G/G): OR = 1.44, 95% CI: 1.19-1.73]. Analysis stratified by ethnicity showed same results in Asian and Caucasian populations. Conclusions: Results revealed nonsignificant association of TNF-alpha-308 genotypes (GG, GA, AA, and GA + AA) and GC. TNF-alpha-308GA genotype showed significant association whereas homozygous genotype AA did not show association with GC risk.