Studies have demonstrated that loss of miRNAs can benefit cancer cells by enhancing tumorigenesis and modulating cells responsiveness to therapies, as seen by the repression of miR-15a/16-1 to increase BCL-2 expression and survival of CLL cells [19] and downregulation of p27kip1 by miR-221-222 in tamoxifen-resistant breast cancer cells [20]. This evidence concerns the gene BCL2 and cancer.