Abstract
BACKGROUND: Many studies have been carried out to test the hypothesis that the NQO1 C609T polymorphism might be associated with the risk of esophageal cancer. However, the results are poorly consistent, partly due to genetic or other sources of heterogeneity. To investigate the association between this polymorphism and the risk of esophageal cancer, a meta-analysis was performed. METHODS: We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of association. The frequency of the putative risk allele in the controls was estimated by the inverse-variance method. Cochran's Q statistic and the inconsistency index (I2) were used to check heterogeneity. Egger's test and an inverted funnel plot were used to assess the publication bias. RESULTS: Our study included eight published case-control studies about the NQO1 C609T polymorphism and esophageal cancer, including a total of 1,217 esophageal cancer patients and 1,560 controls. Overall, a significant association was found between the NQO1 C609T variant and esophageal cancer under a recessive model (OR = 1.647; 95% CI = 1.233-2.200). Regarding histological type, more significant evidence was found for esophageal squamous cell carcinoma (ESCC) (OR = 2.03; 95% CI = 1.29-3.19) than esophageal adenocarcinoma (EAC) (OR = 1.61; 95% CI = 1.01-2.56) under a recessive model. CONCLUSIONS: The meta-analysis suggests that the NQO1 C609T polymorphism considerably increases the risk of esophageal cancer.