RUNX1 and acute myeloid leukemia: ETO (Eight-Twenty-One, also called myeloid translocation gene on 8) fusion gene is regarded as the most frequent abnormality observed among approximately 45% of patients with acute myeloid leukemia (AML) with French-America-British-M2 morphology and an aneuploid karyotype, in which a reciprocal translocation, t (8; 21)(q22; q22) t(8; 21), brings together a large proportion of ETO gene from chromosome 8 and part of the AML1 gene from chromosome 21 to form AML1/ETO fusion gene.