Lymphoma associated chromosomal abnormalities can easily be detected by FISH on tissue imprints. An underused diagnostic alternative

Background: Fluorescence in situ hybridisation (FISH) is useful for detecting specific chromosomal abnormalities in various tumours. In lymphomas, diagnosis is frequently made using paraffin wax embedded tissue. However, FISH performed under these conditions presents potential technical problems and difficulties in interpretation. Aims: To show that FISH using tissue imprints and cytopreps or alternatively, bone marrow (BM) smears, constitutes an easy and rapid strategy to overcome these constraints. Methods: The study comprised 46 patients with lymphoma. Sixty nine tissue imprints, cytopreps, or BM smears were analysed by FISH. Dual colour, dual fusion FISH probes were used to detect the t(8;14), t(11;14), and t(14;18) translocations, whereas a dual colour breakapart FISH probe was used to detect chromosomal translocations involving the BCL6 gene. Results: Tissue imprints and cytopreps were successfully hybridised in all 52 cases, whereas hybridisation was successful in 16 of 17 archival BM smears. All patients could be analysed to identify either the presence or absence of chromosomal translocations. Conclusions: The use of tissue imprints, cytopreps, or BM smears to identify chromosomal abnormalities by FISH is a rapid and useful ancillary approach for diagnostic purposes. Therefore, it could be used on a routine basis whenever fresh samples are available.