Effects of Steroids and Their Antagonists on Breast Cancer Cells: Therapeutic Implications

Steroid hormones regulate the growth of both normal and tumour mammary cells, but the detailed mechanism remains unclear. Regulation is diverse and complex, involving direct effects on the tumour cells and indirect effects via other organs. For this reason, it has been very difficult to interpret data in vivo, and cell culture systems have been extensively used. We use two model systems for study of steroid hormone action in vitro: oestrogen-regulated human mammary tumour cells (ZR-75-I, MCF-7, T-47-D) and androgen-regulated mouse mammary tumour cells (S115).