TP53 and neoplasm: In general, the senescence checkpoint pathway genes such as MAPK [104,105], and overexpression of p53 [reviewed in [106]] and the genes that regulate p53 including ARF (p14ARF in human or p19ARF in mice), p33ING1 [107], PML [108-110], nucleoplasmin or NPM [111] and PTEN [97] are all involved in the senescence-induced tumor suppression program [Reviewed in [19,84]].