As the application of PARP-1 inhibitor can induce a structural change in PARP-1 to pursue the continuous stabilization of PARP-1 and DNA combination, the PARP-1 inhibitor binds to the catalytic domain of PARP-1 to maintain a continuous active state of PARP-1 in cancer cells, and thus the catalytic cycle to return to the inactive state is finally interrupted, resulting in inducing PARP-1 dysfunction [66]. This evidence concerns the gene PARP1 and cancer.