At the beginning of the genetic-guided approach, clinicians primarily focused on high-risk genes, such as BRCA1/2—BReast Cancer 1/2, TP53—tumor protein p53, PALB2 Partner and Localizer of BRCA2-, CDH1—Cadherin 1, STK11—serine/threonine kinase 11 and PTEN—Phosphatase and TENsin homolog deleted on chromosome 10. This evidence concerns the gene BRCA1 and breast cancer.