FISH analysis.

(A) Effect of BCR-ABL expression on DNA repair, as evaluated by FISH. Human parental UT-7 and BCR-ABL transfected UT-7/9 cells were irradiated at 2 and 4 Gy and collected 24 hours later. Histogram shows the percentage of cells with chromosomal abnormalities and SD; 200 metaphases were counted for each point. The percentage of cells with chromosomal abnormalities was extremely low in the UT-7 parental cells and dramatically increased in the BCR-ABL–expressing UT-7/9 cells. (B) Effect of BCR-ABL TK inhibition with AG957 on DNA repair as evaluated by FISH. BCR-ABL–expressing UT-7/9 cells were pretreated with AG957 1 μM for 3 hours, irradiated at 2 Gy, and collected 24 hours later. A marked decrease of the percentage of cells with chromosomal abnormalities was observed after exposure to AG957.