Similarly, Mcl-1 has been shown to be expressed at high levels in the leukaemic stem cell fraction of AML cells when compared to normal haematopoietic stem cells [31] and Mcl-1 over-expression has been shown to have a role in resistance of leukaemic cells to Flt-3 inhibitors [32]. This evidence concerns the gene MCL1 and acute myeloid leukemia.