CDKN2A and head and neck cancer: The epigenetic alterations of CDKN2A (p16; located at 9p21), CDH1 (16q22.1), FHIT (3p14.2), RAR-β (3p24.2), and ATM (11q22.3) have been found to be related to clinical prognosis in cancer of the head and neck [18].