Biologists, toxicologists, risk assessors, and regulators came together November 16-17, 2009, in Oakland, CA for a scientific workshop, organized by Silent Spring Institute Research Director Ruthann Rudel and Dr. Suzanne Fenton from NIEHS, to advance research on how early life exposure to EDCs influences mammary gland development and susceptibility to cancer.
Workshop participants were brought together to develop standard methods for describing changes in mammary gland structure and development, and recommend changes to current tests used by regulatory agencies so that they include more thorough assessment of mammary glands. Another priority was to learn from regulatory agencies what types of studies would be useful to them, so that biologists can design research appropriately and funders have good information about priorities. Progress will ultimately lead to relatively inexpensive and quick chemical test methods that assess developmental effects on the mammary gland and can be interpreted as predictive of adverse effects, such as carcinogenicity, that currently have to be evaluated in expensive, long-term studies
In a number of laboratories, researchers have shown that treatment of pregnant test animals with endocrine disrupting compounds (EDCs) results in changes to the structure of the mammary gland in the offspring. These results suggest that fetal exposure to EDCs may cause permanent changes to the breast that could lead to adverse health effects such as changes in the timing of puberty, problems with lactation, or increased susceptibility to carcinogens. However, this area of research is still emerging, and many questions remain about how to evaluate changes in mammary gland structure and how to link these changes to health. Regulators have been reluctant to rely on mammary gland effects as the basis for limiting exposures because of the lack of consistency in researchers’ methods for reporting the structural changes and inadequate data linking those changes to adverse effects such as cancer.
This workshop was supported by the US Environmental Protection Agency, the National Institute of Environmental Health Sciences, and the California Breast Cancer Research Program.