Researchers have found that metals present in tobacco smoke mimic the effects of estrogens and activate the body?s estrogen receptor, an action that may increase the risk of breast cancer. These metals are a new class of potent environmental estrogens called metalloestrogens, and smoking is a significant route of exposure.
?The ability of tobacco smoke to mimic the effects of estrogens suggests that the contaminants contribute to the etiology of breast cancer,? said Dr. Mary Beth Martin of Georgetown University and principal author of the study. ?However, additional studies are required to clarify the association between cigarette smoking, metalloestrogens, and the disease.?
In the study human breast cancer cells were treated with tobacco smoke condensate (TSC). TSC was found to stimulate breast cancer cell growth, activate the estrogen receptor, and increase the expression of the estrogen regulated genes.
The mammary gland is unique in that it grows and develops throughout the lifetime of a female and estrogens play a central role in the growth and development of the gland. Early life exposure to environmental estrogens such as metalloestrogens may alter mammary gland development and, consequently, breast cancer risk.
This paper has been published online and will appear in the October 2007 issue of Endocrinology, a publication of The Endocrine Society.
Effects of Tobacco Smoke Condensate on Estrogen Receptor-a Gene Expression and Activity
Mary B. Martin, Ronald Reiter, Michael Johnson, Mansi S. Shah, Mary C. Iann, Baljit Singh, Julie K. Richards, Antai Wang, and Adriana Stoica