CDKN2A/p16INK4a (herein indicated as p16INK4a) is a critical tumor suppressor that inhibits the cyclin-dependent kinases CDK4 and CDK6, thereby keeping the retinoblastoma protein (pRB) in a hypo-phosphorylated state, thus leading to G1/S checkpoint activation [25]. Here, CDKN2A is linked to neoplasm.