Clinical and Prognostic Significance of O6-Methylguanine-DNA Methyltransferase Promoter Methylation in Patients with Melanoma: A Systematic Meta-Analysis

Tumor suppressor gene O-6-methylguanine-DNA methyltransferase (MGMT) promoter methylation has been reported in melanoma. However, the clinical and prognostic significance of MGMTpromoter methylation in patients with melanoma remained to be determined. A systematic search was performed to identify eligible papers published. The overall odds ratios (ORs) or hazard ratios and their 95% confidence intervals were calculated. Final 12 eligible publications involving Caucasian population were performed in this study, including 1,071 metastatic melanoma patients, 154 primary melanoma patients, and 211 normal controls. MGMTpromoter methylation was significantly higher in primary or metastatic melanoma than in normal controls (p <0.05). No difference of MGMTpromoter methylation was found in primary and metastatic melanoma (p=0.432). When metastatic melanoma was compared to normal controls, subgroup analysis showed the correlation between MGMTpromoter methylation and different sample materials (tissue: OR = 7.01, p<0.001 and blood: OR = 12.04, p = 0.005). MGMTpromoter methylation was not associated with response to drug therapy and the prognosis in overall survival and progression-free survival for multivariate analysis. Our results show that MGMTpromoter methylation may be correlated with the increased risk of primary or metastatic melanoma. Based on blood samples, MGMTpromoter methylation may become a noninvasive biomarker for the detection of metastatic melanoma. Further additional clinical studies are necessary.