Real-time quantitation of bcr-abl transcripts in haematological malignancies

We have applied an automated real-time quantitative PCR assay using a doubl e-labeled fluorogenic probe to detect t(9;22)-positive cells in haematologi cal malignancies. The results are expressed as the ratio of chimeric bcr-ab l transcripts on abl transcripts. Highly reproducible results were obtained for t(9.73)-positive K562 RNA. Ten copies of bcr-abl DNA from a recombinan t KW-3 plasmid and one positive cell in 10(4) can be detected. Thirty-two p atients with chronic myeloid leukaemia (CML), 25 with acute leukaemia, 12 w ith myelodysplastic syndromes and 7 with other myeloproliferative syndromes were tested. Follow-up data were obtained in bcr-abl positive cases. Resul ts were compared with those of conventional nested RT-PCR and cytogenetics. Real-time quantitative RT-PCR values correlated well with both these metho ds. However, in some cases the only means of detecting early relapse or bla stic transformation was to examine the kinetics of real-time quantitative R T-PCR. Thus, real-time quantitative RT-PCR appears suitable for the diagnos is and follow-up of patients with the t(9;22) translocation.