KMT2A and acute myeloid leukemia: We found that mice in the miR-550-1 + MLL-AF9 group exhibited slower AML development than did those in the MLL-AF9 only group (median overall survival: 33 vs. 27 days, P=0.010; Fig. 4I), suggesting that suppressing miR-550-1 did contribute to the sustained maintenance of AML driven by the MLL-AF9 fusion gene.