BRCA1 and breast cancer: Women with a BRCA1 mutation have a >65% lifetime risk of triple negative breast carcinoma [7–9], a subtype which accounts for 10–15% of breast cancers [10] and which are thought to originate in luminal progenitor cells (reviewed in [11]) and have a particularly poor prognosis [12] and a high frequency of TP53 mutations [13].