CDKN2A and gastric cancer: To validate whether epigenetic silence of p16 expression correlates negatively with transcription of Cbx7 and its related components in vivo, we first analyzed p16 methylation status quantitatively by DHPLC and MethyLight in human primary gastric carcinoma samples (GC), the corresponding cutting-edge normal tissues of GC (GCN), and human normal gastric mucosa biopsies from non-cancer patients (Normal).