Clinical Significance of O-6-Methylguanine-DNA-Methyltransferase Promoter Methylation in Patients with Esophageal Carcinoma: A Systematic Meta-Analysis

The correlation between O-6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation and esophageal cancer remains controversial. This study was conducted to evaluate the clinical effect of MGMT promoter methylation on esophageal carcinoma patients.A literature search was conducted in the PubMed, EMBASE, EBSCO, and Cochrane Library databases. The overall OR and corresponding 95% CI were calculated using the random-effects model.Finally, 17 eligible studies were identified in this meta-analysis; these studies included a total of 1,368 patients with esophageal carcinoma and 1,489 with nonmalignant controls. MGMT promoter methylation was significantly higher in esophageal carcinoma tissue samples than in nonmalignant tissue samples (OR 3.64, p < 0.001). Promoter methylation of the MGMT gene was not associated with gender, cigarette smoking, drinking behavior, or tumor differentiation, but MGMT promoter methylation was correlated with age (≥60 vs. <60 years: OR 1.64, p = 0.028), lymph node status (positive status vs. negative status: OR 2.39, p = 0.024), and clinical stage (stages 3-4 vs. 1-2: OR 10.59, p < 0.001).Our findings suggest that MGMT promoter methylation may be correlated with esophageal cancer carcinogenesis and could be associated with age, lymph node status, and clinical stage.