The cell death response to DNA damage is discussed in this Perspectives piece with cancer as the backdrop because DNA damaging agents (DDA) are widely used to treat cancer. From decades of clinical results, we learn that DDA have cured some cancers but their toxicity is temporary in most cancers due to emergence of DDA-resistant cancer cells. Investigation of DDA-activated genes, proteins, and pathways, known collectively as the DNA damage response (DDR), has uncovered the inner workings of DDR that protect the genome to sustain life. Paradoxically, however, DDR can also activate death. Current knowledge on DDA-activated death and hypotheses for how DDR may determine when and where to execute death are discussed. Given that cancer cells suffer from DDR defects, which account for their initial sensitivity to DDA, future therapeutic development may exploit those cancer-specific DDR defects to selectively create death-inducing DNA lesions, without using DDA, to kill DDA-resistant cancers
