KMT2A and leukemia: Rearrangements involving the MLL1 gene and its associated partners are commonly observed in different types of leukemia, including precursor B cell acute leukemias (B-ALLs), T cell acute lymphoblastic leukemias (T-ALLs), acute myeloid leukemias (AMLs), myelodysplastic syndromes (MDSs) mixed lineage (biphenotypic) leukemias (MPALs) and secondary leukemias [1].