Treatment of FLT3/ITD AML cell lines with an FLT3 inhibitor increased NHEJ efficiency and decreased misrepair. (A-B) Relative repair efficiency (A) and misrepair frequency (B) in MOLM-14 cells with and without CEP-701 treatment. (C-E) Colony PCR and sequence analysis of randomly selected mirepaired NHEJ products in MOLM-14 cells with and without CEP-701 treatment. (C) An agarose gel image of the colony PCR products. The size of a PCR product from a correctly repaired DSB is 628 bp. PCR products of a smaller molecular weight indicate that deletions have occurred during repair. Molecular size markers are indicated on the left. (D-E) Scatter plots showing the distribution of deletion size (D) and nucleotides of microhomology (E) at DSB repair junctions in randomly selected misrepaired NHEJ products. P values are shown for all graphs. Vertical lines represent SD. The mean is indicated as a solid horizontal line in scatter plots.