CDKN2A and head and neck cancer: As indicated in table 2, the significant association was not found between p16 hypermethylation and OS of esophageal cancer (HR 1.25, 95% CI: 0.38–4.13), gastric cancer (HR 4.64, 95% CI: 0.87–24.64), head and neck cancer (HR 0.96, 95% CI: 0.65–1.40), brain cancer (HR 1.33, 95% CI: 0.43–4.07), or bladder cancer (HR 1.77, 95% CI: 0.59–5.38).