MGMT and cancer: Many tumor suppressor genes are inactivated by this mechanism in cancer such as the adenomatous polyposis coli (APC) [29], retinoblastoma (Rb) [30], Von Hippel-Lindau (VHL), BRCA1 [31], and several other genes that are involved in DNA repair (MGMT; O-6-Methylguanine-DNA Methyltransferase), cell cycle progression (p16INK4a, p15INK4b), apoptosis (DAPK; death-associated protein kinase-1), or antioxidation (GSTP1; Glutathione S-Transferase P-1) [32].