Although combined Wee1 and CHK1 inhibition has been reported in various cancer types [24]-[26], including AML [13], our study confirmed the enhanced anti-leukemic activity with a different CHK1 inhibitor, LY2603618, than has been previously reported (MK-8776, PF-00477736, AR458323) and found similar synergistic anti-leukemic activity. Here, WEE1 is linked to acute myeloid leukemia.