Previous NPC studies reported that P16 gene expression was reduced or absent in the majority of patients, which may result in the increase of cellular proliferation (Gulley et al., 1998; Makitie et al., 2003) Hypermethylation of P16 gene which causes P16 gene inactivation plays an important role in NPC carcinogenesis. The gene discussed is CDKN2A; the disease is nasopharyngeal carcinoma.