In a new study, scientists at Dana-Farber Cancer Institute provide the first details of the cancer cell machinery that carries out breast cancer’s relentless growth. As well as the link to estrogen, the study has shown that the male hormone androgen also spurs the growth of some breast tumours in women.
Androgen is not exclusively a male hormone as it is also involved in the normal development of secondary sexual characteristics in women. The study was published in the journal Cancer Cell in July 2011 and provides scientists with several new areas for research. Specifically the cell proteins that snap into action in response to androgen, so research into future therapies could investigate potential drugs that could block those proteins in order to slow or stifle tumor growth.
This is particularly applicable, according to researchers, to many breast cancer patients who are not helped by standard hormone-blocking agents such as tamoxifen. About 70-75 percent of breast tumours are fueled by estrogen and when estrogen becomes lodged in an estrogen receptor, it sets off a chain of events that prompts the cell to grow and proliferate. Drugs such as tamoxifen block estrogen from entering the receptor, thereby thwarting the growth process.
The remaining 25-30 percent of breast cancers, dubbed ER-negative tumors, lack estrogen receptors, and thus do not respond to tamoxifen and similar agents. It is known that the majority of breast tumours – even those with estrogen receptors – also have receptors for androgen, but the reasons for these receptors’ presence, and how they might influence tumor growth, have been unknown.
Good news for women with androgen positive tumours, but am I alone in wishing that scientists would spend as much time investigating the positive role of natural progesterone in preventing breast cancer? For valuable information on breast cancer see the excellent book ‘What Your Doctor Doesn’t Tell You About Breast Cancer’ by Dr John Lee, David Zava and Virginia Hopkins.