Association between the Glutathione-S-transferase T1 null genotype and esophageal cancer susceptibility: a meta-analysis involving 11,163 subjects

BACKGROUND: Glutathione-S-Transferase T1 (GSTT1) null genotype has been shown to be associated with the risk of esophageal cancer. However, the results remain inconsistent. Thus a comprehensive meta-analysis was conducted to assess the strength of association between GSTT1 null genotype and the risk of esophageal cancer. MATERIALS AND METHODS: A literature search of PubMed, Embase, China National Knowledge Infrastructure (CNKI) and Wanfang databases up to March 31, 2017 was conducted and 30 eligible articles with 4482 cases and 6681 controls were finally recruited. The strength of correlation between GSTT1 polymorphism and the susceptibility of esophageal cancer was assessed by the crude odds ratios (ORs) with 95% confidence intervals (CIs). Subgroup analyses and sensitivity analyses were performed to further identify the association. RESULTS: GSTT1 null genotype significantly increased the risk of esophageal cancer (OR = 1.20; 95% CI 1.04–1.40; P < 0.05). In a subgroup analysis by ethnicity, GSTT1 null genotype was correlated with a significantly increased risk of esophageal cancer among Asians (OR = 1.33; 95% CI 1.12–1.58; P < 0.05), instead of Caucasians or Africans (OR = 0.91; 95% CI 0.65–1.26; P > 0.05 for Caucasians and OR = 1.32; 95% CI 0.98–1.77; P > 0.05 for Africans). In the analysis by histological type, GSTT1 null genotype was correlated with a significantly increased risk of esophageal squamous cell carcinoma (OR = 1.34; 95% CI 1.12–1.61; P < 0.05), particularly among Asians (OR = 1.54; 95% CI 1.30–1.82; P < 0.05), but not among Caucasians or Africans (OR = 0.87; 95% CI 0.48–1.57; P > 0.05 for Caucasians and OR = 1.32; 95% CI 0.98–1.77; P > 0.05 for Africans). In addition, there is no significant correlation between GSTT1 null genotype and the risk of esophageal adenocarcinoma (OR = 0.98; 95% CI 0.71–1.35; P > 0.05). CONCLUSIONS: Our findings demonstrate that GSTT1 null genotype significantly increases esophageal cancer risk, particularly in Asians.