Decreased expression of MGMT in correlation with aberrant DNA methylation in esophageal cancer patients from North India

O-6-methylguanine-DNA methyltransferase, DNA repair gene, has been found to be involved with the pathogenesis of the esophageal cancer. DNA hypermethylation and other factors have been suggested to downregulate O-6-methylguanine-DNA methyltransferase. In this communication, the methylation status of O-6-methylguanine-DNA methyltransferase gene and the corresponding O-6-methylguanine-DNA methyltransferase protein expression in esophageal cancer from North India has been studied. In all, 80 samples of tumor tissue along with adjacent normal tissue as controls were analyzed for messenger RNA level of O-6-methylguanine-DNA methyltransferase gene, protein expression, and subcellular localization. The messenger RNA expression was studied using real-time quantitative polymerase chain reaction, protein expression, and its subcellular localization by Western blotting and immunohistochemistry. DNA methylation was assessed through methylation-specific polymerase chain reaction. Clinicopathological parameters were re...