Megestrol acetate

Biotechnology

Biology

Growth factor

Megestrol

Endocrinology

Estrogen

Receptor

Tamoxifen

Progesterone receptor

Triple-negative breast cancer

Endocrine system

Estrogen receptor

Immunology

In vivo

Insulin-like growth factor

Antigen

Internal medicine

Pathological

Hormone

Oncology

Medicine

Progestogen

Breast cancer

Mammary gland

Cancer

The Breast

Background: In order to come to a better understanding of one of the receptors analyzed in relation to breast cancer and its relation to gestagens, we have studied the progesterone receptor (PR) in association to megestrol acetate (MA) and come across an interesting and contradictory connection between these two and insulin like growth factor I (IGF-I). Objective: We aimed to see if there were any associations between PR and endocrine changes during MA treatment. Materials and methods: Breast tumor PR before treatment and IGF-I, steroids, steroid binding proteins and insulin before and during treatment were measured in 17 postmenopausal women with breast cancer treated sequentially with tamoxifen 40 mg/day followed by MA 160 mg/day in altering three-month periods Results: During MA treatment periods IGF-I and insulin levels increased significantly. Significant positive correlations were found between PR content, measured by enzyme immuno assay, and an increase in serum IGF-I, but not between PR and any other endocrine change among those measured. Conclusions: Malignant as well as normal breast tissue secretes considerable amounts of growth hormone and IGF-I in vitro. This activity is stimulated in vitro by gestagens. The association between PR and the increase in IGF-I may therefore reflect a direct PR-mediated action of MA on malignant as well as normal human breast tissue in vivo. It could therefore be argued that the treatment may be contra productive in the case of MA.

Progestogen can stimulate growth factor production in breast tissue of women with breast cancer