Because of the effect of MAPK on the expressions of DNMT1, HDAC2, and p16 induced by PAR4-AP, it is likely that the inhibitions of DNMT1 and HDAC2 induced by PAR4 activation are involved in the expression of p16 via MAPK signals in ESCC cells. The gene discussed is DNMT1; the disease is esophageal squamous cell carcinoma.