Development of the normal breast, carcinogenesis of its epithelium breast, and progression of breast cancer are regulated by hormonal factors. The best defined of these factors are the endocrine steroids, peptides, and other molecules produced by the secretory cells of the ovaries, pituitary, endocrine pancreas, thyroid, and adrenal cortex. After their initial interaction with either nuclear or cell surface receptors, these hormones regulate cellular function. In addition, normal and malignant mammary tissues are able to synthesize locally acting hormone-like substances. One class of these factors is known as the paracrine hormones, factors released by one cell type which then modulate the function of neighboring cells of the same or different mammary cell type. A recently described variation on this theme is the class of juxtacrine factors. These factors are growth-regulatory molecules that remain exposed on a cell surface and modulate adjacent cells by contact. A third general class of local factors is that of the autocrine (or intracrine) hormones, soluble molecules synthesized by one cell type that act back on the same cell type through surface or intracellular receptors. It is of considerable interest that after their synthesis, polypeptide factors may be routed either to a cell surface receptor or to a nuclear site.
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism