It is well known that cell cycle-associated senescence is mediated by the P14ARF–Mdm2–P53 tumor suppressor axis [25], with senescence generally characterized by up-regulated P53 and Cyclin-dependent kinase inhibitor 1 (Cdkn1, P21) and down-regulated senescence-associated-Cyclin activity [26]. This evidence concerns the gene MDM2 and neoplasm.