 The t(8;21) RUNX1-ETO translocation is one of the most frequent cytogenetic abnormalities in acute myeloid leukemia (AML).     ///    "In RUNX1-ETO(+) patient samples, differing classes of activating c-KIT receptor tyrosine kinase mutations have been observed. "    ///    Analysis of reconstituted animals showed that RUNX1-ETO;c-Kit(D814V) coexpression resulted in 3 nonoverlapping phenotypes.     ///    "In contrast, RUNX1-ETO;c-Kit(T417I?418-419) coexpression promoted exclusively AML in a fraction (51%) of reconstituted mice. "    ///    "To test whether distinct subtypes of activating c-KIT mutations differ in their leukemogenic potential in association with RUNX1-ETO, we used a retroviral transduction/transplantation model to coexpress RUNX1-ETO with either c-Kit(D814V) or c-Kit(T417I?418-419) in murine hematopoietic stem/progenitor cells used to reconstitute lethally irradiated mice. "