MOLECULAR DIAGNOSIS OF T(11-14) IN MANTLE CELL LYMPHOMA USING 2-COLORINTERPHASE FLUORESCENCE IN-SITU HYBRIDIZATION

t(11;14) is observed in up to 70% of mantle cell lymphoma (MCL) cases and is therefore an important diagnostic element. In routine practice, detection of t(11;14) by conventional cytogenetic techniques is hinde red by the low yield and quality of tumour metaphases. Molecular techn iques (Southern blot, PCR) are unable to detect a large number of 11q1 3 breakpoints due to scattering over distances up to 1 Mb. Using 23 MC L patients with karyotypically determined t(11:14) and eight negative controls, we have devised a two-colour interphase F1SII assay for dete ction of the 14q+ chromosome. We chose an 11q13 probe telomeric to the major 11q13 translocation cluster sites and an IGII probe centromeric of the 14q32 breakpoints. This method detected the translocation in a ll 23 t(11:14) positive patients, with an overall average of 60% nucle i showing colocalized signals, Widespread application of this techniqu e will constitute an important diagnostic aid in clinical management o f MCL patients. Since FISH is a convenient method for retrospective an alysis of large numbers of patient specimens, this method should contr ibute to an accurate estimation of t(11:14) frequency in MCL and other chronic B-cell malignancies and consequently to their better nosologi cal characterization.