Immunoglobulin heavy chain and major translocation cluster bcl-1 gene rearrangements were detected in all 29 (100%) and in 12 (41%) of 29 mantle cell lymphoma samples, respectively.
Median values of normalized cyclin D1 expression determined by real-time quantitative polymerase chain reaction were 1.32 for mantle cell lymphoma, 0.02 for B-cell chronic lymphocytic leukemia, 0.009 for diffuse large B-cell lymphoma, 0.004 for marginal zone lymphoma, 0.002 for follicular lymphoma compared with 0.0003 for reactive lymphoid tissue, and 0.00004 for sorted B cells of healthy donors.
The recognition of cyclin D1 expression in PC of a significant minority of CLL/SLL can be a diagnostic aid and should not lead to the diagnosis of focal mantle cell lymphoma.
We arrived at the following conclusions: (a) FISH with this BCL1 YAC probe is an efficient method for the detection of the t(11;14) and of the corresponding involvement of the BCL1 locus in this lymphoproliferative disorder; (b) the majority of BCL1-positive atypical CLLs by French-American-British criteria may carry 13q14 deletions; (c) the recognition of this cytogenetic subset of atypical CLL, sharing some immunological and cytogenetic features with mantle cell lymphoma, may be important, because these patients usually present isolated peripheral blood and marrow lymphocytosis, with or without mild to moderate spleen involvement, and may require early cytotoxic treatment.
When cyclin D1 was overexpressed by the Eμ-cyclin D1 transgene, ATA B cells progressed to further diffused lymphoma in aged mice, including in various lymph nodes with accumulation of IgM<sup>hi</sup>IgD<sup>lo</sup>CD5<sup>+</sup>CD23<sup>-</sup>CD43<sup>+</sup> cells, resembling aggressive human mantle cell lymphoma.
It is widely acknowledged that FISH is the most consistently useful test to identify the juxtaposition of the CCND1 and IGH genes in mantle cell lymphoma and is regarded as the 'gold standard'.
A simple antigen retrieval method for the optimal demonstration of cyclin-D1 overexpression in formalin-fixed paraffin-embedded cases of mantle cell lymphoma.
Quantitative monitoring of cyclin D1 expression: a molecular marker for minimal residual disease monitoring and a predictor of the disease outcome in patients with mantle cell lymphoma.