AML1 is commonly fused to RUNTX1T1 (ETO) in a chromosome translocation t(8;21)(q22;q22), which is one of the most frequent karyotypes in AML [42]. RUNX gene mutations have been identified in some cases of MDS and generally infer unfavorable prognosis [30, 31]. The gene discussed is RUNX1; the disease is acute myeloid leukemia.