MECOM and acute myeloid leukemia: We find that in contrast to 5-fluorouracil (5-FU) or polyinosinic:polycytidylic acid (poly(I:C)) stimulation, short-term in vivo exposure to recombinant thrombopoietin (TPO) selectively and significantly increases the fraction of cycling Evi1+ LT-HSC and multipotent progenitor 1 (MPP1) cells that induce an aggressive Evi1+ iKMT2A-MLLT3-driven AML upon transplant.