Numerous high-risk epithelial lesions in familial breast cancer.

To assess the occurrence of high-risk epithelial lesions in women of breast cancer families with and without a BRCA mutation.,Prospective study of women at very high risk of breast cancer undergoing prophylactic mastectomy (68 BRCA1 mutation carriers, 14 BRCA2 mutation carriers and 24 non-BRCA mutation carriers).,The prevalence of high-risk lesions is equal in women with a BRCA1 or a BRCA2 mutation, but is higher in non-BRCA mutation carriers: all lesions 43% versus 71% (p=0.02), atypical lobular hyperplasia 26% versus 67% (p=0.001), atypical ductal hyperplasia 17% versus 42% (p=0.01), lobular carcinoma-in situ 15% versus 29% (p=0.10) and ductal carcinoma-in situ 9% versus 17% (p=0.25). The presence of high-risk lesions is related to absence of a BRCA mutation and to age over 40 years.,Women with an autosomal dominant family history for breast cancer, with and without a BRCA mutation are prone to develop high-risk epithelial lesions, especially over 40 years.