BRCA1 and breast cancer: Pathogenic variants of the BRCA1 and BRCA2 genes confer a 72% and 69% risk of a woman developing breast cancer by the age of 80 years, respectively, with the average age at diagnosis some 20 years younger than for sporadic cancers.1 For BRCA1 carriers there is also an increased risk of developing a more aggressive cancer phenotype (triple negative) with a worse prognosis.2,3