These proteins are the results of genomic translocations, hence BCR-ABL originates from t (9;22) and the so-called Philadelphia chromosome, which is mostly found in chronic myeloid leukemia but occasionally also in AML and ALL cases, while MLL-AF9 derives from t(9;11) and is the most frequent mixed-lineage leukemia (MLL) gene rearrangement in childhood AML [19,20,21]. The gene discussed is KMT2A; the disease is acute myeloid leukemia.