Four classes of drugs were used: cytotoxic drugs routinely used to treat AML (daunorubicin, cytarabine and etoposide); the proteasome inhibitor bortezomib, which is being trialled for AML; [19] CDK7/9 inhibitors that inhibit transcription and thereby reduce levels of short-lived proteins such as MCL-1; [16, 17, 42] and BH3 mimetics targeting different pro-survival BCL-2 family members: ABT-737 (which targets BCL-2, BCL-XL and BCL-W) [24, 28], ABT-199 (venetoclax) (specific for BCL-2) [25], A-1331852 (specific for BCL-XL) [34, 43] and S63845 (specific for MCL-1) [26]. Here, MCL1 is linked to acute myeloid leukemia.