Quantitative RNA slot-blot analysis of CCND1/cyclin D1 expression in suspected mantle cell lymphoma

Abnormal CCND1 expression is found in the majority of mantle cell lymphomas (MCL) and in a minority of other mature B cell malignancies. Its evaluation can therefore aid diagnostic classification, in conjunction with clinical, morphological, immunophenotypic and cytogenetic analysis. We describe a rapid slot-blot hybridization technique allowing quantitative assessment of CCND1 expression relative to beta-actin, with a sensitivity cut-off of approximately 10%. This allowed clear separation (P < 0.01) of CCND1 MCL (0.89 +/- 0.4; range 0.23-1.81; n = 25) from control samples (0.02 +/- 0.04; range 0-0.09; n = 22) on limited quantities of RNA (1-3.5 microg). Of nine samples in which a potential diagnosis of MCL lymphoma was based on morphological analysis of paraffin-embedded material, without adequate immunophenotype analysis, all were CCND1 negative and subsequent immunophenotype demonstrated features compatible with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) (CD5+, CD23+, FMC7-) in all cases tested. This study demonstrates the feasibility of slot-blot CCND1 quantification and the importance of the availability of cryopreserved material.