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[Gonadotropin-releasing hormone receptors in human breast cancer tissue]
L Kiesel1, M Kaufmann, F Haeseler
1Abteilung für Gynäkologische Endokrinologie, Universitäts-Frauenklinik, Heidelberg.
Abstract:
Analogues of gonadotropin-releasing hormone (GnRH) are presently being investigated for the treatment of metastatic breast cancer. Although their effects are thought to be mediated via the suppression of gonadotropins and gonadal steroids, they could possibly also act directly on the tumour. The binding of a GnRH-agonist to membrane fractions of 97 primary human breast carcinomas was investigated. In 43 cases (44%) the presence of specific GnRH receptor binding sites (above 3 fmol/mg membrane protein) was shown. GnRH receptor content was 6.2 fmol/mg membrane protein in estradiol receptor (ER) positive tissues and in ER negative tissues 2.0 fmol/mg membrane protein (p less than 0.05). Progesterone receptor (PR) positive contained 5.2 fmol/mg protein and PR negative carcinoma contained 2.0 fmol/mg membrane protein. In postmenopausal women GnRH receptor concentration was 5.4 and 2.9 fmol/mg membrane protein, respectively, in ER positive and negative tissues (p less than 0.05) whereas 4.4 and 5.2 fmol/mg membrane protein, respectively, in PR positive and negative samples. Binding of GnRH was positive (above 3 fmol/mg protein) in 33% premenopausal and in 54% of postmenopausal cases. Further clinical studies with GnRH analogues will clarify the therapeutic value of GnRH receptor determination in breast cancer.
Insights
Gonadotropin-releasing hormone (GnRH) receptors are present in human breast cancer tissue. Their presence correlates with hormone receptor status and menopausal status, suggesting a potential therapeutic target for breast cancer.
Area of Science:
- Endocrinology
- Oncology
- Molecular Biology
Context:
- Analogues of gonadotropin-releasing hormone (GnRH) are being explored for metastatic breast cancer treatment.
- GnRH analogues' effects are primarily attributed to suppressing gonadotropins and gonadal steroids.
- A potential direct action of GnRH analogues on tumor cells is also under investigation.
Purpose:
- To investigate the presence and characteristics of specific GnRH receptor binding sites in primary human breast carcinomas.
- To determine the correlation between GnRH receptor expression and key clinical parameters such as estrogen receptor (ER), progesterone receptor (PR) status, and menopausal status.
Summary:
- Specific GnRH receptor binding sites were detected in 43% of 97 primary human breast carcinomas analyzed.
- GnRH receptor content was significantly higher in estrogen receptor-positive (6.2 fmol/mg) and progesterone receptor-positive (5.2 fmol/mg) tissues compared to their negative counterparts.
- Receptor expression varied between premenopausal (33% positive) and postmenopausal (54% positive) women, with higher levels in ER-positive postmenopausal tissues.
Impact:
- These findings suggest that GnRH receptors are present in a subset of breast cancers.
- The correlation with hormone receptor status and menopausal status indicates a potential role for GnRH signalling in breast cancer.
- Further clinical studies are warranted to elucidate the therapeutic value of targeting GnRH receptors in breast cancer treatment.