Effects of oestrogens and anti-oestrogens on normal breast tissue from women bearing BRCA1 and BRCA2 mutations
Abstract
There is considerable interest in whether anti-oestrogens can be used to prevent breast cancer in women bearing mutations in the BRCA1 and BRCA2 genes. The effects of oestradiol (E2), tamoxifen (TAM) and fulvestrant (FUL) on proliferation and steroid receptor expression were assessed in normal breast epithelium taken from women at varying risks of breast cancer and implanted into athymic nude mice, which were treated with E2 in the presence and absence of TAM or FUL. Tissue samples were taken at various time points thereafter for assessment of proliferative activity and expression of oestrogen and progesterone receptors (ERalpha and PgR) by immunohistochemistry. Oestradiol increased proliferation in the breast epithelium from women carrying mutations in the BRCA1/2 genes, those otherwise at increased risk and those at population risk of breast cancer. This increase was reduced by both TAM and FUL in all risk groups. In the absence of E2, PgR expression was reduced in all risk groups but significantly more so in the BRCA-mutated groups. Subsequent E2 treatment caused a rapid, complete induction of PgR expression in the population-risk group but not in the high-risk or BRCA-mutated groups in which PgR induction was significantly ...Continue Reading
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Mutations involving BRCA1, found on chromosome 17, and BRCA2, found on chromosome 13, increase the risk for specific cancers, such as breast cancer. Discover the last research on breast cancer BRCA1 and BRCA2 here.