MCL1 and B-cell chronic lymphocytic leukemia: For example, miR-181a and miR-181b are downregulated in chronic lymphocytic leukemia (CLL) [138] and overexpression of these miRNAs sensitize CLL cells to fludarabine mediated cell death by targeting B-cell lymphoma − 2 (BCL − 2), myeloid cell leukemia-1 (MCL-1) and X-linked inhibitor of apoptosis protein (XIAP) [178].