Here, we report that cyclin-dependent kinase inhibitor 2C (CDKN2C) as a member of the cyclin-dependent kinase inhibitors is a target of the PML/RARα oncofusion protein in leukemogenesis of acute promyelocytic leukemia (APL).We found that CDKN2C was markedly downregulated in APL blasts compared with normal promyelocytes.