Abstract:Objective To investigate the prognostic value of metaphase chromosome karyotyping comparing with fluorescence in situ hybridization (FISH) in patients with chronic myeloid leukemia (CML). Methods The metaphase chromosome karyotyping was performed in 171 cases of CML patients and the FISH was performed in 218 specimens of CML patients. Results Among the 171 cases of CML patients, Ph chromosome was detected in 116 cases (68%) by metaphase chromosome karyotyping, and 22 cases (13%) of CML patients had other chromosome abnormalities. Among the 218 specimens of CML patients, FISH showed that 174 specimens (80%) were BCR-ABL (+). Of the CML patients, 76% were detected with the expression of P210 fusion protein, 3% were detected with the co-expression of P210 and P190, and 0.95% only expressed P190 fusion protein. Also, FISH revealed that 18% of the CML patients had partial deletion of der (9). Conclusions The detection rate of FISH is higher than that of metaphase chromosome karyotyping. Metaphase chromosome karyotyping can detect Ph chromosome and other chromosome abnormalities. FISH can detect the existence of BCR-ABL fusion gene. Also, FISH can show different types of BCR-ABL fussion proteins and partial deletion of der(9). The two mothods can be used to show more information of CML patients, and play important roles in the diagnosis of CML.