Notably, the Kmt2a-Mllt1 myeloid leukemia can be established in the Pax5 +/− background with similar dynamics as in the Pax5 +/+ background confirming that a reduced Pax5 gene dosage does not influence the leukemogenic activity of Kmt2a-Mllt1 (Supplementary Fig. 4). This evidence concerns the gene MLLT1 and myeloid leukemia.