ATP2A1 and head and neck squamous cell carcinoma: The findings from the discovery profiling, AGAP2, ALPL, ANGPTL2, ATP2A1, CALML5, DNAJC5G, FDFT1, GNMT, GPT, HOXB3, KLK11, LMF1, LY6D, LYNX1, MAL, MGC16275, MRGPRF, NKPD1, SH2D3C, TNNI2, and ZNF876P, were further analysed using quantitative methylation-specific PCR (Q-MSP) in an independent large series of HNSCC specimens.