Rapid detection of BCR/ABL and PML/RARA using fluorescence in situ hybridization in cytospin preparations

Fluorescence in situ hybridization (FISH) is increasingly used as an adjunct to conventional cytogenetic analysis in the diagnosis of haematological malignancies and in monitoring minimal residual disease. FISH, however, is generally performed on slides prepared after short-term sample incubation and therefore, whilst faster than conventional cytogenetics, still requires a minimum of 2 days for a result to be obtained. A simplification of the FISH procedure is reported using uncultured cytospin preparations of bone marrow or peripheral blood for the rapid diagnosis of the BCR-ABL and PML-RARa gene rearrangements. It demonstrates that culturing has no effect on the ratio of normal to abnormal cells in the nondividing population. Data is presented from an analysis of 24 cases in whom unequivocal results were obtained in less than 12 h and in complete concordance with results obtained by conventional cytogenetics and/or interphase FISH.