Objective: To study the bcr/abl fusion gene in chronic myeloid leukemia (CML) cases with Philadelphia chromosome(Ph) negative, and variant Ph translocations and other chromosome anomalies.

Methods: The status of bcr/abl fusion gene in 8 kinds of chromosome anomalies was tested with dual-color fluorescence in situ hybridization (D-FISH) technique.

Results: The positive hybridization was demonstrated in 3 cases of variant Ph CML and other 7 cases of standard Ph, respectively. In 2 cases of Ph-negative CML, one case that had karyotype such as 46,XY,t(9;18) showed positive hybridization, the other case with 46,XY,inv(2) showed negative result.

Conclusions: The result demonstrates that D-FISH technique is reliable for detecting bcr/abl fusion gene. The existence of negative bcr/abl fusion gene CML implies that some other initial events inducing CML might have occurred in such cases.