Although B2m depletion did not change the growth of MLL-AF9 cells in vitro and in NSG mice, it inhibited AML progression in WT and Rag2−/− mice, as evidenced by the decrease of tRFP657+ cells (B2m-sgRNA-transduced cells) (Fig. 3c, d). Here, KMT2A is linked to acute myeloid leukemia.