Seventy per cent of breast
cancers are
luminal carcinomas that express
estrogen receptor alpha (ER). For several decades, its expression has been used as a therapeutic target in patients with
breast cancer. These
therapies are aimed at blocking ER or inhibiting
ligand synthesis. The expression of
progesterone receptors (PR) is evaluated as a prognostic factor together with ER. It has been shown that there are two predominant PR
isoforms with different molecular weight,
isoform A and
isoform B, which are not distinguished by immunohistochemical techniques. The available evidence indicates that the PR
isoform ratio may have both a prognostic and predictive value of the response to antiprogestin treatment. In
luminal mammary
carcinomas,
androgen receptors (AR) are expressed in a high percentage and the AR/ER or AR/PR ratio could be a prognostic factor. In ER negative (-)
tumors, AR expression is an
indicator of poor prognosis and it is proposed that they may be susceptible to
antiandrogen treatment. Finally, the expression of
glucocorticoid receptors (GR) would be an
indicator of good or bad prognosis in
luminal or ER-
tumors, respectively. In ER-
tumors,
metastases express higher levels of nuclear GR than primary
tumors and
therapies that block GR could improve the efficacy of
chemotherapy. Given the crosstalk of pathways triggered by different
hormone receptors, it is possible that in the future, a therapeutic scheme can be administered that contemplates the expression of ER, PR
isoforms, AR and GR.