MCL1 and B-cell chronic lymphocytic leukemia: In the case of chronic lymphocytic leukemia (CLL), macrolide SPLMs like pladienolide-B and FD-895 were able to modulate the myeloid cell leukemia factor 1 (MCL1) gene transcript isoforms (larger-MCL1L: larger-anti-apoptotic, and shorter, MCLS: pro-apoptotic) after treatment in CLL-B cells.