BRCA1 and breast cancer: The majority of breast tumors that develop in carriers of BRCA1 mutations - the products of which are involved in HR - are triple-negative breast cancers (TNBCs) overlapping with the gene expression-defined subtype of breast cancer known as ‘basal-like breast cancer’, whereas BRCA2 mutation-associated breast cancers have a less restricted immunohistochemical phenotype [5-7].