Aims In recent years the genetic aberrations associated with diffuse large B-cell lymphoma and the new subtype described in the 2008 revision of the WHO classification, ‘B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma’ have been increasingly well defined. Recurrent genetic abnormalities include rearrangements involving MYC (8q24), BCL2 (18q21) and BCL6 (3q27); as the prognostic and therapeutic implications associated with these abnormalities are clarified their accurate identification at diagnosis is becoming increasingly critical. We describe our experience of using a panel of fluorescence in situ hybridisation (FISH) probes on formalin-fixed paraffin-embedded tissue sections in the diagnostic work-up of 162 patients with non-Burkitt high grade B-cell non-Hodgkin's lymphomas (HG-BNHL).

Methods BCL6, IGH-BCL2 and MYC status were determined prospectively in sequential patients presenting with HG-BNHL, with respect to the presence of rearrangements and copy number changes. Small numbers of samples were analysed retrospectively or were studied at relapse in previously untested patients.

Results FISH analysis was successful in 160/162 (99%) cases, with abnormalities detected in 118/160 (74%).

Conclusions FISH analysis of formalin-fixed paraffin-embedded tissue sections is a highly reproducible technique with an excellent success rate for the detection of genetic abnormalities which will play an increasingly important role in improving risk stratification of patients with HG-BNHL.