Breast cancer is the most common in female cancer patients worldwide, the population frequencies of pathogenic variants in breast cancer predisposition genes belongs to the highest among the high-penetrant cancer predisposition genes overall (especially in BRCA2 and BRCA1), the risk of cancer in carriers of pathogenic variants is well described and the guidelines for their cancer prevention and treatment are available in the clinical practice worldwide24–26. This evidence concerns the gene BRCA1 and breast cancer.