Supplementary Material for: Clinical Significance of O-6-Methylguanine-DNA-Methyltransferase Promoter Methylation in Patients with Esophageal Carcinoma: A Systematic Meta-Analysis
Background: 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. Methods: 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. Results: 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). Conclusions: 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.