DETECTION OF THE BREAKPOINT CLUSTER REGION ABL FUSION IN CHRONIC MYELOID-LEUKEMIA WITH VARIANT PHILADELPHIA-CHROMOSOME TRANSLOCATIONS BY IN-SITU HYBRIDIZATION

Fluorescence in situ hybridization (FISH) technique has been successfu lly used to detect the BCR-ABL gene fusion in chronic myeloid leukemia (CML) with the classic form of the Philadelphia chromosome (Ph). We a pplied FISH to study three CML patients showing variant Ph chromosome (either complex or simple type). The results demonstrate that the use of a yeast artificial chromosome (YAC)-derived probe (D107F9) and a co smid probe (cos-abl 8), specific for sea and ABL genes respectively, a llows also the detection of the BCR-ABL fusion in CML patients with va riant Ph.