Cry1/Cry2 deficient double mutant mice that also carry inactivated Tp53 gene copies exhibit longer cancer-free survival and somewhat extended lifespan than p53-deficient mice without Cry mutations, although both groups virtually never reach the lifespan of normal mice.[24] This is believed to be associated with increased propensity toward apoptosis by the p53-independent mechanism, conferred by deficiency of Cry proteins.[24]. The gene discussed is TP53; the disease is cancer.