Here we show that wild-type MPL expression is increased in a fraction of human AML samples expressing RUNX1-ETO, a fusion protein created by chromosome translocation t(8;21), and that up-regulation of Mpl expression in mice induces AML when coexpressed with RUNX1-ETO.     ///    Mpl expression is not regulated by RUNX1-ETO in mouse hematopoietic progenitors or leukemic cells.     ///    Thrombopoietin/MPL participates in initiating and maintaining RUNX1-ETO acute myeloid leukemia via PI3K/AKT signaling.. 