Moreover, the epigenetic repression of DNA repair enzymes due to MGMT (O6-methylguanine DNA methyltransferase) promoter hypermethylation or acquired DNA mismatch repair deficiencies, an aberrant cell cycle progression including multiple mutations of regulatory genes, the dysregulations of miRNAs or the induction of pro-tumorigenic processes including elevated epithelial–mesenchymal transition (EMT) or angiogenesis and many more, are important factors for GBM resistance [4,9,10]. The gene discussed is MGMT; the disease is glioblastoma.