Given our recent finding that inhibitors of LSD1 promote myeloid differentiation in MLL-translocated AML through disruption of the protein:protein interaction of the transcription repressor GFI1 with LSD1 [9], it was of note that guides targeting GFI1 and the LSD1/CoREST complex gene RREB1 scored highly in the screen (Fig. 1b). The gene discussed is KMT2A; the disease is acute myeloid leukemia.