biostudies-literatureUnknown15(4)Deb SLarge numbers of breast cancers arise within a familial context, either with known inherited germline mutations largely within DNA repair genes, or with a strong family history of breast and/or ovarian cancer, with unknown genetic underlying mechanisms. These cancers appear to be different to sporadic cases, with earlier age of onset, increased multifocality and with association with specific breast cancer histological and phenotypic subtypes. Furthermore, tumours showing homologous recombination deficiency, due to loss of <i>BRCA1</i>, <i>BRCA2</i>, <i>PALB2</i> and <i>CHEK2</i> function, have been shown to be especially sensitive to platinum-based chemotherapeutics and PARP inhibition. While there is extensive research and data accrued on risk stratification and genetic predisposition, tCancers1346https://www.ebi.ac.uk/biostudies/studies/S-EPMC9953970biostudies-literaturePrognostic and Predictive Biomarkers in Familial Breast Cancer.PMC9953970Fox SBDeb SChakrabarti AfalsePrognostic and Predictive Biomarkers in Familial Breast Cancer.Large numbers of breast cancers arise within a familial context, either with known inherited germline mutations largely within DNA repair genes, or with a strong family history of breast and/or ovarian cancer, with unknown genetic underlying mechanisms. These cancers appear to be different to sporadic cases, with earlier age of onset, increased multifocality and with association with specific breast cancer histological and phenotypic subtypes. Furthermore, tumours showing homologous recombination deficiency, due to loss of <i>BRCA1</i>, <i>BRCA2</i>, <i>PALB2</i> and <i>CHEK2</i> function, have been shown to be especially sensitive to platinum-based chemotherapeutics and PARP inhibition. While there is extensive research and data accrued on risk stratification and genetic predisposition, t2023-01-01T00:00:00Z2023 Feb2025-04-05T07:24:29.052Z2025-04-05T07:24:29.052ZS-EPMC99539703683168710.3390/cancers15041346