We previously demonstrated that CARM1 blocks the myeloid differentiation of normal hematopoietic stem/progenitor cells (HSPCs) by promoting the assembly of a repressive RUNX1 complex15, and that Carm1 knockout in adult mouse HSPCs prevents the development of acute myeloid leukemia (AML), driven by either the AML1::ETO or MLL::AF9 oncogenes, but only modestly decreases long-term hematopoietic stem cell (HSC) numbers24. This evidence concerns the gene MLLT3 and acute myeloid leukemia.