OBJECTIVETo study the expression of bcr/abl hybridized gene in chronic myeloid leukemia (CML), acute lymphatic leukemia (ALL) and polycythemia vera (PV), and its clinical significance.

METHODSThe bcr/abl hybridized gene of interphase metaphase cells of bone marrow in 67 such patients were investigated with a probe of dual color-dual fusion translocation fluorescence in situ hybridization (D-FISH).

RESULTSIn 38 CML patients, 34 (89.5%) were positive, with one having a typical t (9; 22) at first, which changed into negative after having been treated with interferon for 38 months. In another patient, 60 days after post-allogeneic peripheral blood stem cell transplantation (PBSCT), the cytomorphology and cytogenetics were in completely remission. But 3% cells were bcr/abl positive as detected by D-FISH. Six (25%) of 24 ALL patients were positive for Bcr/abl fusion gene, which was negative in 2 PV patients. Three patients suspected of having CML were also negative and one of these three was finally diagnosed as suffering from primary thrombocythemia and one, acute myeloid leukemia (M(2a)) as detected by ETO/AML(1) gene, though the other one was still not confirmed. Two (67%) of the 3 bcr/abl negative CML patients and 5 (87%) of the 6 bcr/abl positive ALL patients had refractory leukemia.

CONCLUSIONbcr/abl hybridized gene is accurately detected by a probe of dual color-dual fusion translocation fluorescence in situ hybridization, which can serve as an effective index for clinical diagnosis, estimation of prognosis and monitor of minimal residual disease in some hematopathies.