BRCA1 and breast cancer: To extend the possibility to identify mutations responsible for breast cancer inheritance, we applied multigene panel sequencing to a small cohort of hereditary BC/BOC families, which shared the following criteria: (1) being negative for BRCA1/2 truncating or missense deleterious mutation, after standard Sanger sequencing; being willing to provide; (2) blood and DNA samples from affected and unaffected individuals to establish LCLs and to perform segregation analysis; and (3) tumor tissue from at least one affected individual to perform LOH studies.