CDKN2A and myeloid leukemia: To establish whether FOXM1 regulates chemotherapy resistance in myeloid leukemia, we utilized previously developed transgenic mice lacking the alternative reading frame (ARF) tumor suppressor: (a) Arf–/– C57BL/6 and (b) Rosa26-FoxM1b Tg;Arf–/– C57BL/6 (25).