MGMT and neoplasm: GBM patients are stratified into two categories according to the methylation status of the O-6-methylguanine-DNA methyltransferase gene (MGMT) that repairs the DNA damages induced by TMZ and the patients whose tumor contains methylated MGMT have an overall survival of 21.7 months compared to the 12.7 months of those carrying unmethylated MGMT (9).