The identification of the BCL2 translocation in 1984 [130] and the description of the miR-15a/16-1-mediated post-transcriptional mechanism of regulation of Bcl2 in 2005 [17] were fundamental steps for the development of one of the most effective drugs for the treatment of CLL, venetoclax. The gene discussed is BCL2; the disease is B-cell chronic lymphocytic leukemia.