DOT1L and leukemia: Although development of such compounds has still been in its infancy [4], activities of DOT1L inhibitors (e.g., compounds 1 and 2) against MLL-rearranged leukemia (16–18, 41) and EZH2 inhibitors (e.g., compound 5) against EZH2-mutated lymphoma [40] have demonstrated the potential as well as ample opportunities for this direction.