Importantly, the two functions of p53 are distinguished by differences in p53 levels; i.e., (1) hardly-detectable levels of p53 under normal conditions are associated with extended lifespan and cancer suppression; and (2) accumulated p53 is associated with premature aging and with senescent and/or apoptotic cells [55,56], which are also characterized by p53 overexpression [72]. The gene discussed is TP53; the disease is cancer.