KMT2A and cancer: The MLL (mixed lineage leukaemia) gene has more than 30 known fusion partners [9,10], and retroviral transduction experiments with MLL-ENL fusion showed that the multipotent myeloid progenitors and committed myeloid progenitors could respond to an MLL fusion protein to become leukaemic, suggesting the existence of cancer stem cells distinct from multipotent stem cells of the tissue of origin [11].