MGMT and cancer: Other intensely methylated genes are EDNRB (Endothelin Receptor Type B), methylated in 97% of primary HNC tissues, and RARB (Retinoic Acid Receptor Beta), involved in transcriptional control (199, 200), and the tumor suppressor genes PTEN, DAPK (death-associated protein kinase), MGMT (O6-methylguanine-DNA methyltransferase), involved in DNA repair, CDH1/ECAD (E-cadherin), involved in cell adhesion, and RASSF1 (Ras association domain-containing protein 1), involved in cell cycle control, apoptosis, and cell adhesion, inactivation of which is present in several cancers (201).