It is expressed through the p53-p21Cip1-cyclin-dependent kinase (CDK)/cyclin or the p53-independent CDK/cyclin pathway (p53-p21Cip1-CDK/cyclin or p53-independent CDK/cyclin pathway (p53-p21Cip1-CDK/cyclin or p53-independent CDK/cyclin pathways) and promotes leukemia stem cells senescence. The gene discussed is CDKN1A; the disease is leukemia.