A study incorporated human leukemia cells treated with SP600125, an anti-inflammatory and anticancer drug that inhibits c-Jun N-terminal kinase, to generate an increase in p21 expression as well as p21 phosphorylation, thereby preventing its binding with proliferating cell nuclear antigen, a DNA polymerase cofactor, while also inactivating caspase-3 and consequently apoptosis[95]. Here, CDKN1A is linked to leukemia.