MCL1 and B-cell chronic lymphocytic leukemia: Finally with regard to miRNAs and CLL, miR-181b was frequently down-regulated in CLL patients with disease progression [18, 19] as it targets MCL-1 and BCL2 [18], which are important for cancer cell survival, and low expression of this miRNA was associated with poor prognosis as indicated by treatment-free survival (TFS) [18, 19].