MCL1 and acute myeloid leukemia: We had previously reported that, compared to AML cells expressing two copies of wtRUNX1, in the isogenic AML cells expressing heterozygous mtRUNX1, RUNX1 depletion caused greater sensitivity to homoharringtonine (HHT or omacetaxine)-induced cell death, associated with reduced levels of c-Myc, c-Myb, MCL1 and Bcl-xL [12].