This observation is also in agreement with the impact of the Menin inhibitor MI-503 on MLL-rearranged leukemia cells,26,27 and other inhibitors of epigenetic factors, for example, DOT1L28 and EZH2.29 Menin inhibition resulted in a slight increase in apoptotic cells after 2 weeks, which might be a consequence of myeloid differentiation (Suppl. This evidence concerns the gene MEN1 and leukemia.