Since administration of high doses of enoxacin (>50 μM) for more than 1 day is detrimental for cancer cell viability18,23, we incubated cells for 24 hours before IR and probed for DDR factors including 53BP1, pS/TQ, pATMS1981 and γH2AX by quantitative immunofluorescence. The gene discussed is TP53BP1; the disease is cancer.