Trisomy 8 detection in Ph+ CML patients using conventional cytogenetic and interphase fluorescence in situ...

We examined bone marrow (BM) cells from 6 Philadelphia chromosome positive (Ph+) chronic myeloid leukemia (CML) patients in advanced phase of the disease using conventional cytogenetic techniques and fluorescence in situ hybridization (FISH) for detection of an extra chromosome 8. All patients showed mosaicism for trisomy 8 as a secondary chromosome abnormality. For FISH, we used the D8Z5 probe specific for the centromeric region of chromosome 8 and analyzed 300 interphase nuclei and a variable number of mitoses for each patient. The percentages of metaphases carrying trisomy 8 were similar with both techniques, whereas the percentage of interphase nuclei showing three hybridization spots indicative of trisomy 8 was significantly lower than that in metaphases. This finding suggests that cells with a supernumerary chromosome 8 may have a cell cycle time shorter than that of disomic cells.