In about two-thirds of CLL cases, B-cell proliferation is stimulated by miR-15a and miR-16-1 downregulation as a consequence of 13q14 deletion; an inverse correlation between miR-15a/16-1 and the antiapoptotic gene BCL2 expression has been observed, while CLL cell lines with miR-15a/16-1 downregulation showed an increased BCL2 expression and resistance to apoptosis. Here, BCL2 is linked to B-cell chronic lymphocytic leukemia.