RESUMO
OBJECTIVE: To evaluate the sensitivity and specificity of dual-color and dual-fusion interphase fluorescence in situ hybridization (D-FISH) in determining the tumor load in patients with chronic myeloid leukemia (CML) receiving imatinib therapy. METHODS: The BCR-ABL fusion gene was detected by FISH in 24 cases of chronic myeloid leukemia treated with imatinib. The sensitivity and specificity of D-FISH were compared with those of single-fusion FISH (S-FISH) and RT-PCR. RESULTS: D-FISH was more sensitive and specific than S-FISH. In normal control subjects, the cutoff rates of D-FISH and S-FISH were 0.73% and 6.24%, respectively, showing a significant difference between them. In 24 CML cases receiving imatinib treatment, the positivity rates of S-FISH and D-FISH were 7/24 (29.2%) and 13/24 (54.2%), respectively. The results of D-FISH had a high correlation to that of RT-PCR. CONCLUSION: With lower false positive and false negative results, D-FISH can be used as a sensitive and specific method for monitoring the changes of the tumor load in CML patients during imatinib treatment.