There is evidence of BRCAness and PARP inhibitors inducing synthetic lethality in cancers that are known to have HR-deficient pathways, such as high-grade serous ovarian cancer (HGS-OVCa), advanced prostate cancer, and pancreatic cancers (Bell et al., 2011; Carnevale and Ashworth, 2015; Mateo et al., 2015; Waddell et al., 2015; Lord and Ashworth, 2016). This evidence concerns the gene PARP1 and cancer.