SF3B1 and B-cell chronic lymphocytic leukemia: Conversely, DM CLL cells were more sensitive to the splicing inhibitor H3B-8800 (IC50: 0.00346 μM) compared with Mdr MT CLL cells (IC50: 0.05331 μM) (Figure 5B), consistent with the known role of H3B-8800 in targeting SF3B1 mutations.