With refined knowledge of the biological mechanism of BRCA1/2 tumor suppressor functions over the past decade, the concept of “BRCAness” was introduced as: “A phenocopy of BRCA1 or BRCA2 mutation; it describes the situation in which an HRR defect exists in a tumor in the absence of a germline BRCA1 or BRCA2 mutation.” The new understanding of BRCAness has driven wider adoption of Precision Medicine approaches, PAPR inhibitor specifically, to treat sporadic BRCA-mutant cancer. Here, BRCA1 is linked to cancer.