CDKN2A and cancer: Mutations, homozygous deletions or inactivation by methylation in p16INK4a have also been observed across several cancers, e.g., pancreatic, esophageal, bladder and liver cancer and familial melanoma31,32, homozygous deletions in bladder, kidney, pancreas and ovary tumors33–35, and inactivation through methylation in cancers of the breast, prostate, head and neck, and hepatocellular carcinomas36–39.