Tumor necrosis factor-alpha promoter polymorphism 308 G/A is not significantly associated with esophageal cancer risk: a meta-analysis

Many studies have investigated the association between Tumor necrosis factor-α-308 G>A (rs1800629) and the risk of esophageal cancer. However, their results are inconsistent. Therefore, we performed a meta-analysis of available data to investigate any possible association between this polymorphism and esophageal cancer risk. We searched PubMed, EMBASE, Web of Science, and the CNKI database for articles published up to 2016. Crude and adjusted odds ratio with 95% confidence intervals were calculated using fixed or random effects models. We used a dominant model (GA+AA vs GG), a recessive model (AA vs GG+GA), an over-dominant model (GG+AA vs GA), and allele frequency (G vs A) to identify any association. Eleven studies with 5617 participants were included in the meta-analysis. Our results suggest that TNF-α-308 G>A (rs1800629) is not significantly associated with a risk of esophageal squamous cell carcinoma and esophageal adenocarcinoma. For genetic association studies, negative results of meta-analysis have a high level of evidence, and these results are important in this era of high-throughput sequencing-based precision medicine.