The "portrait" of hereditary breast cancer.

Five to ten per cent of all breast carcinomas are of hereditary origin. Many of them have been associated to mutations in the BRCA1 and BRCA2 susceptibility genes. No "BRCA3" gene has been found to account for the non-BRCA1/BRCA2 breast cancer (BRCAx) families, and BRCAx tumors are increasingly believed to originate from multiple distinct genetic events. Phenotype studies have questioned the existence of specific "portraits" among hereditary breast carcinomas (HBC). They have shown that most BRCA1 tumors have a "basal (epithelial)-like" aspect, while BRCA2 and BRCAx HBC are more heterogeneous. HBC have also been submitted to genetic analyses, notably with the objective of resolving the heterogeneity of BRCAx lesions. The present review aims to summarize recent data on BRCA1, BRCA2, and BRCAx HBC, including hypotheses on the origin of BRCA1 tumors and their paradoxical relations to estrogen-sensitivity.