For nick DNA-binding affinity of XRCC1 wild-type (Fig. 3C) and the cancer-associated variants (Fig. S9) to the repair intermediate with oxidatively damaged 3′-8-oxodG:A ends, we also obtained a decrease in the nick-binding affinity of XRCC1 variant R280H (KD: 116 nM), while all other mutants exhibited wild-type level of KD values (Fig. 3D). The gene discussed is XRCC1; the disease is cancer.