RESUMO
To investigate the significance of duel-color fluorescence in situ hybridization (D-FISH) in monitoring the response to interferon alpha (IFN-alpha) therapy in patients with chronic myeloid leukemia (CML), the D-FISH method was employed to detect the proportion of the interphase nuclei cells with bcr/abl fusion gene in the bone marrow of patients with CML before and after IFN-alpha therapy, and the results were compared with those of bcr/abl fusion mRNA by RT-PCR and Philadephia chromosome (Ph) by conventional cytogenetic analysis. The results showed that the mean detectable rate of bcr/abl fusion gene before and after IFN-alpha therapy was 96.4% and 58.6% respectively, in 22 patients who were bcr/abl-positive before IFN-alpha therapy by D-FISH method, was 94.0% and 70.1% respectively, in 2 patients of Ph-negative before treatment. Major, minor and no responses were seen respectively in 4, 4 and 14 cases from 22 patients by D-FISH method. The results also showed a good correlation with the analysis of RT-PCR and conventional cytogenetics. In conclusion, D-FISH method could directly detect the bcr/abl fusion gene of the interphase cells in bone marrow of patients with CML. It can overcome the defect of conventional cytogenetic methods which analyze only the cells in metaphase and the drawback of RT-PCR unable to quantify the bcr/abl fusion gene. D-FISH provides a more convenient and reliable method for evaluating the degree of clone remission to patients with CML after IFN-alpha therapy.