MCL1 and acute myeloid leukemia: Importantly, AML cell survival is dependent on MCL-1 expression (Kadia et al., 2019), with elevated MCL-1 levels driving intrinsic and acquired AML drug resistance (Pan et al., 2015; O’Reilly et al., 2018), and also correlating with disease relapse (Li X. X. et al., 2019).