KMT2A and acute lymphoblastic leukemia: Interestingly, a similar process of plasticity-driven evasion of lineage-specific immunotherapy following CD19-directed immunotherapy has recently been described following CD19-CAR in CLL with Richter transformation into a plasmablastic lymphoma49 and in two patients with MLL rearranged ALL transformed to AML50, and following bispecific CD3-CD19 antibody in ALL51.