Here we show that ABL1 kinase inhibitor imatinib can be applied to increase the anti-leukemia effect of DNA damage response inhibitors (DNA-PKi and ATRi) and intracellular signaling inhibitors (PI3Ki) in AML1-ETO and/or NUP98-PMX1 leukemia cells. The gene discussed is RUNX1T1; the disease is leukemia.