The relationship between hormones and carcinogenesis is complex, as shown by research demonstrating the link between mutations in the androgen receptor and prostate cancer, and another project in which mammary gland growth is shown to be mediated by binding to an estrogen receptor in the stroma. Further research is ongoing into how estrogen receptors function to modulate the growth and development of the ovaries. An interesting and unexpected development of this work has been the discovery of an ERs in the prostate. In searching for novel nuclear receptor proteins, the research group found a new receptor that had a high affinity for binding estrogen. The group has since identified the human homologue of the ER found in the rat prostate.
Many environmental chemicals exhibit estrogenic activity, both naturally occurring and man-made.
Estrogenic compounds may interact with estrogen, ERs, or other hormones and transcription factors in the biochemical pathway of hormone activity. Concerns about the risks to human health posed by endocrine disruptors have led to the identification of many such environmental chemicals. It still remains to identify potentially harmful chemicals, define mechanisms of action, clarify mutagenic properties and genetic susceptibility, specify risk factors from exposure, and develop therapies and prevention strategies. With the help of new technologies and approaches, scientists are striving to understand the often powerful effects that very small amounts of environmental hormones and hormone-like chemicals may have on humans and wildlife.