MGMT and glioblastoma: GBM is one of the best characterized genomic cancers, several types are distinguished according to their transcriptional profile (proneural, neural, classical, and mesenchymal or edge, edge-like, core, core-like), genetics (mutations in IDH gene), and epigenetics (CpG island methylation phenotype (CIMP), O6 methylguanine-DNA methyltransferase (MGMT) promoter methylation) [8,9,10,11,12].