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

// Ming Luo 1, * , Yuan Yang 2, * , Dongmei Luo 3, * , Liang Liu 4, * , Yuening Zhang 5 , Feifan Xiao 5 , Jingcheng Yang 2 , Chengdong Zhang 1,2, 6, 7 , Shen Fu 6, 7 , Zhiguo Luo 1 1 Department of Clinical Oncology, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei, China 2 School of Life Sciences, Fudan University, Shanghai, China 3 School of Mathematics and Physics, Anhui University of technology, Maanshan, Anhui, China 4 Department of Oncology, Fudan University Shanghai Cancer Center, Fudan University, Shanghai, China 5 Medical Scientific Research Center, Guangxi Medical University, Nanning, Guangxi, China 6 Department of Radiation Oncology, Shanghai Proton and Heavy Ion Center, Shanghai, China 7 Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China * These authors have contributed equally to this work and share first authorship Correspondence to: Shen Fu, email: shen_fu@hotmail.com Zhiguo Luo, email: oncology_group@163.com Keywords: esophageal cancer, TNF-α-308 G/A, meta-analysis, risk, association Received: June 06, 2016      Accepted: October 21, 2016      Published: November 4, 2016 ABSTRACT 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.