BRCA1 and ductal breast carcinoma in situ: We observed a higher relative risk of DCIS with a BRCA2 mutation (OR = 11.3, 95% CI 3.9–32.6, p < 0.0001) than a BRCA1 mutation (OR = 3.3, 95% CI 1.4–7.9, p = 0.01).