The objectives of this study are to (1) evaluate the effectiveness of family history as a tool for identifying women at high risk of breast cancer, (2) determine the impact of pathogenic variants in BRCA1, BRCA2, PALB2, ATM, and CHEK2, as well as the presence of a high polygenic risk, on breast cancer diagnosis within the HNP cohort, and (3) characterize the population of women newly identified or missed based on the utilization of different combinations of genetic and family history information. This evidence concerns the gene ATM and breast cancer.