MGMT and glioblastoma: GBM is characterized by different genetic alterations, such as mutations in the isocitrate dehydrogenase-1 or -2 genes, methylation of the O6-methylgunine-DNA methyltransferase (MGMT) promoter, and overexpression of the gene encoding the epidermal growth factor receptor (EGFR) [4,5,6,7].