CDKN2A and neoplasm: The evaluation of the impact of the absence of Ink4/Arf locus and p53 on aging has not been studied nowadays, as null or heterozygous mice for these tumor suppressors develop several type of tumors at an early age (Donehower et al., 1992; Serrano et al., 1996), but it would be feasible in an inducible knockout or knockdown system.