Less than 50% of CLL patients have deletion, alteration or downregulation of mir-15a and mir-16-1 [76] in the DLEU2-mir-15-16 cluster, which both target BCL2 [77] and lead to enhanced BCL2 expression and increased resistance of leukemic cells to apoptosis [77]. Here, BCL2 is linked to B-cell chronic lymphocytic leukemia.