Application of fluorescence in situ hybridization technique in diagnosis of variant Ph chromosome translocation and Ph-negative chronic myelocytic leukemia

Objective: To explore the value of fluorescence in situ hybridization (FISH) technique in diagnosis of variant Ph chromosome translocation (VT) and Ph chromosome-negative chronic myelocytic leukemia (CML).

Methods: Nine CML patients with VT and 2 Ph chromosome-negative CML patients confirmed by R banding were assayed with dual color-dual fusion BCR/ABL probe by FISH.

Results: The 9 patients with VT involved chromosomes 1, 3, 5, 12, 13, 15, 17 and 21 besides chromosomes 9 and 22, and some of them showed recurrent aberrations; FISH results were positive and the signal feature was 2R2G1Y. The 2 Ph-negative CML patients had normal karyotypes; FISH was positive and the signal feature was 1R1G2Y and 1R1G1Y respectively.

Conclusions: FISH can provide better diagnosis for CML with VT and Ph-negative CML. Abnormal karyotype and marker gene changes can be assessed based on the signal feature of the positive cell. So FISH is a complementary method to banding technique in diagnosis of CML.