FLT3/ITD cells showed decreased Ku70/86 and increased DNA Lig IIIα levels. (A) Western blotting analysis of Ku70, Ku86, and DNA Lig IIIα in cell extracts of BaF3/ITD and parental BaF3 cells. Actin was used as a loading control. (B) Western blotting analysis of DNA Lig IIIα, Ku70, and Ku86 in cell extracts of MOLM-14 and REH cells with and without CEP-701 treatment. Actin was used as a loading control. (C-E) NHEJ assay in MOLM-14 cells treated with siRNA for DNA Lig IIIα. (C) Western blotting analysis of DNA Lig IIIα in cell extracts. Actin was used as a loading control. (D) Relative NHEJ efficiency. (E) Misrepair frequency. (F) A scatter plot showing the distribution of deletion size. P values are shown for all graphs. Vertical lines represent SD. The mean is indicated as a solid horizontal line in scatter plot.