By specific FISH probes, including the IGK enhancer region, we detected 10 additional cryptic IGK juxtapositions to <i>CCND3</i> (6 cases) and <i>CCND2</i> (4 cases) in MCL that overexpressed, respectively, these cyclins.
IGH and IGK gene rearrangements were mainly found in mantle cell lymphomas, small lymphocytic lymphomas, extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue and diffuse large B-cell lymphomas.
B-cell clonality was detected by combined use of the IGH and IGK multiplex PCR assays in all 260 definitive cases of B-cell chronic lymphocytic leukemia (n=56), mantle cell lymphoma (n=54), marginal zone lymphoma (n=41) and follicular lymphoma (n=109).