The cyclin dependent kinase inhibitor 2A (CDKN2A), which functions in cell cycle control by a combination of 2 CDK kinase inhibitor isoforms and 1 alternate open reading frame isoform as p53 protein stabilizer, is the most frequent altered tumor suppressor gene, with loss-of function mutations in more than 90% of PDAC [129,130]. The gene discussed is CDKN2A; the disease is neoplasm.