p16INK4a is a tumor suppressor that functions to inhibit the cyclin D1-CDK4/6 complex thus, promoting cell cycle regulation, however, in cancer cells this interaction is often suppressed, leading to transcriptional silencing of p16INK4a that results in uncontrolled G1/S transition and replicative immortality [36,76]. The gene discussed is CDKN2A; the disease is cancer.