In December 2014, the FDA approved the first PARP inhibitor, olaparib, as a monotherapy for patients with advanced BRCA1/2-mutated ovarian cancer who were treated with three or more prior lines of chemotherapy based on the promising results from a Phase II clinical trial (NCT0107662) (Kaufman et al., 2015; Arora et al., 2021). Here, PARP1 is linked to ovarian cancer.