BCR/ABL-induced ROS causes DSBs in S and G₂/M cell cycle phases. (A) Representative 32Dcl3 parental and BCR/ABL-32Dcl3 nuclei containing γ-H2AX foci. Only the foci colocalizing with DAPI are shown; nuclei borders are marked in blue. Numbers below show the mean number ± SD of foci per nucleus. (B) γ-H2AX foci were detected in 32Dcl3 parental (P) and BCR/ABL-32Dcl3 (B/A) cells isolated in G₀/G₁, S, and G₂/M cell cycle phases. Results show mean percentages plus or minus standard deviation of cell cycle distribution of the cells containing γ-H2AX foci. (C) DSBs (depicted by arrows) in the DR-GFP sequence (left panel) and Na⁺/K⁺ ATPase sequence (right panel) were detected by LL-PCR followed by Southern blotting in BCR/ABL-positive cells (B/A), but not in parental (P) and PDTC-treated BCR/ABL-positive cells (B/A-PDTC). The G/C-rich stretches near the predicted DSB sites are listed.