Despite potent in vitro activity, AS-6 demonstrated a very limited effect on the proliferation of the MLL leukemia cells (GI50 ~ 50 μM) (Supplementary Fig. 4), possibly due to poor cell permeability associated with the higher polarity of this compound (clogP = 1.6, tPSA = 120), Supplementary Table 2. Here, KMT2A is linked to leukemia.