CDK9 and acute myeloid leukemia: Similarly, CDKI-73 is an orally bioavailable CDK9 inhibitor that can downregulate the anti-apoptotic proteins BCL-2, MCL-1, and XIAP, leading to remarkable antitumor effects in acute myelogenous leukemia (AML) [25], while iCDK9 exhibited more than 600-fold selectivity toward CDK9, compared to CDKs 1, 2, 4, 7, and 8 [32].