Khanh T Do et al. reported in phase 1 preliminary clinical data that combining CHK1 inhibitor Prexasertib with the PARP inhibitor Olaparib shows therapeutic promise in patients with high-grade serous ovarian cancer (HGSOC) who carry Breast Cancer Gene (BRCA) mutations and have experienced disease progression despite prior PARP inhibitor treatment. Here, PARP1 is linked to breast cancer.