By analyzing normal esophageal mucosa, esophageal dysplasia, and ESCC, Guo et al. also found clear evidence of accumulated methylation events during ESCC progression, which included accumulation of promoter region methylation of genes MGMT, p16, BRCA1, MLH1, CDH1, RARβ2, DAPK, and APC (28, 71). The gene discussed is CDKN2A; the disease is esophageal squamous cell carcinoma.