BRCA1 and breast cancer: Meta-analysis studies have shown that the cumulative breast cancer risks for BRCA1 and BRCA2 pathogenic variant carriers by age 70 are 57–65% and 45–49%, respectively (Antoniou et al., 2003; Chen and Parmigiani, 2007), highlighting the difficulties with predicting the course of disease even in known pathogenic variant carriers and the importance of considering family history as well as other genetic and environmental factors (Lee et al., 2019).