Résumé
There is emerging evidence from clinical and experimental data that familial breast cancers, including BRCA1 and BRCA2 related forms, could be in fact estrogen-sensitive. Interactions between BRCA1 gene expression and estrogens have been reported. On one hand, BRCA1 expression could be induced by estradiol in experimental models. On the other hand, recent studies indicate that BRCA 1 interacts with and regulates the activity of estrogen receptor ERalpha. Endogenous or exogenous estrogens, such as oral contraceptive, may also increase the risk of breast cancer in BRCA1 mutation carriers in clinical studies. Conversely, prophylactic oophorectomy and anti-estrogens may decrease the risk of familial breast cancer. Prospective studies are thus required to estimate the potential benefits of estrogen suppression therapies for prevention or adjuvant treatment of familial breast cancer. Oral contraception and hormonal replacement therapy after menopause should be used with caution in BRCA1 or BRCA2 mutation carriers.