However, RUNX1-ETO expression requires additional co-operating mutations in KIT, FLT3, RAS, ASXL1, and ZBTB7A, -9q, or –Y for the complete leukemic transformation of cells, and consistent with this idea, additional chromosomal aberrations are detected in almost 70% of t(8;21)-positive AML [21]. The gene discussed is RUNX1; the disease is acute myeloid leukemia.