Large aberrations (>1 Mb) beyond the FISH-targeted loci were identified in 78% (14/18) of CLL cases, including many clinically relevant findings such as t(14;18)(q32.33;q21.33)/IGH::BCL2, t(2;18)(p11.2;21.33)/IGK::BCL2, and the gain of 2p involving MYCN in certain cases. This evidence concerns the gene BCL2 and B-cell chronic lymphocytic leukemia.