APAF1 and head and neck squamous cell carcinoma: Hypermethylation of these 13 genes have been described in independent studies in other types of tumors such as DBC1 in lymphomas and lung cancer [33], LATS2 in head and neck squamous cell carcinoma, astrocytoma or breast cancers [34], ASPP1 in hepatocellular carcinoma [35], DAPK1 in Multiple Myeloma [36] and chronic lymphocytic leukemia [37], APAF1 in acute myeloblastic leukaemia [38] and gastric cancer [39], TP73 in cervical carcinomas [40], CDKN1C in diffuse large B cell lymphoma [41] and pancreatic ductal neoplasms [42] and finally, hsa-miR-34b/c in ovarian and colorectal cancers [43].