Also, treatment of Ras cells with both cytarabine and nutlin-3, an inhibitor of Mdm-2 induced degradation of p53, caused a further increase in p21Cip1 expression, which was paralleled by increased expression of differentiation markers (Figures 7A,B,C) and is consistent with a recent report that nutlin-3 can cause maturation in AML cells [44]. This evidence concerns the gene CDKN1A and acute myeloid leukemia.