We investigated the response of 4 cancer cell lines: NCI-H460, NCI-H1299, PANC-1 and Panc 10.05 treated with 5 DDRis targeting ATM (KU55933), ATR (AZD6738), DNA-PKcs (NU7441), PARP (AZD2281) and Rad 51 (B02), at various concentrations (0.1-10 μM) and irradiated with 6 MV x-rays or 9.9 keV/μm protons (dose-weighted LET in water). Here, PARP1 is linked to cancer.