PTK2 and head and neck squamous cell carcinoma: Examples include recurrent amplification of known oncogene MYC; protein kinase genes MET, PTK2 (also known as FAK1) and FGFR1; apoptosis-related FADD; histone lysine methyltransferase gene WHSC1L1; NDRG1 (N-myc downstream regulated 1) which is frequently altered in human cancers including HNSCC but whose roles remain controversial [50]; cell cycle genes CCNE1, CDK6 and E2F3; and others listed in S1E Table.