Mcl-1 is a highly unstable antiapoptotic Bcl-2 family member playing a crucial role in survival of hematopoietic progenitor cells and various malignant hematopoietic cells, including AML cells by inhibiting activation of the intrinsic mitochondria-mediated apoptosis pathway triggered by initiator proapoptotic Bcl-2 members, including Bad and BIM, and executed by effectors, including Bax and Bak [9,10]. The gene discussed is BCL2L11; the disease is acute myeloid leukemia.