Germline Genetic Testing for Breast Cancer Risk: The Past, Present, and Future.

The field of germline genetic testing for breast cancer (BC) risk has evolved substantially in the last decade. The introduction of multigene panel testing (MGPT) led to an urgent need to understand the cancer risk associated with several genes included in the panels. Although the research on understanding the cancer risk associated with mutations in several genes continues, there is also a need to understand the modifying effects of race and ethnicity, family history, and BC pathology on the prevalence of germline mutations and associated BC risk. Furthermore, polygenic risk scores (PRSs) to predict BC risk in patients with or without germline mutations in cancer-predisposition genes are now available for clinical use, although data on the clinical utility of PRSs are lacking. In patients with advanced BC associated with BRCA1/2 mutation, olaparib and talazoparib are now approved for treatment. In addition, molecular profiling studies are being used to clarify the BC tumor biology in mutation carriers to identify potential therapeutic options. In this article, we discuss these advances in the field of germline genetic testing and highlight current limitations and implications for clinical care.