October is Breast Cancer Awareness Month and a good time to review NIEHS efforts to fight this disease. As scientists learn more about how environmental exposures affect risk of developing breast cancer, their knowledge can be translated into measures aimed at prevention. That is why a key report developed by the congressionally established Interagency Breast Cancer and Environmental Research Coordinating Committee is called, “Breast Cancer and the Environment — Prioritizing Prevention.”
NIEHS continues to fund research into the most frequently diagnosed cancer in women and to make information publicly available, so individuals can take steps to reduce their risk and researchers can use the latest findings to design new studies.
Sponsored research programs
Several long-term studies and research consortia receive funding from NIEHS. This year marks a decade of the NIEHS-supported Sister Study (see sidebar). An offshoot of that study, the Two-Sister Study, focuses on young-onset breast cancer.
Together with the National Cancer Institute (NCI), NIEHS also supports the Breast Cancer and the Environment Research Program (BCERP). Grant-funded researchers are working across scientific disciplines, involving racially and ethnically diverse communities, and expanding their study of risk factors that precede breast cancer, such as breast density (see story).
The NIEHS web site has a wealth of information on several environmental health topics, including breast cancer. The page highlights findings from the Sister Study and other research.
You will also find descriptions on ongoing studies, a fact sheet on Breast Cancer Risk and Environmental Factors (1MB) and links to other sources of information, such as NCI.
Recent research findings
A look at some of the latest research published by NIEHS scientists and grantees reveals the variety of approaches scientists are taking to better understanding breast cancer.
Researchers in the National Toxicology Program (NTP) Reproductive Endocrinology Group, led by Sue Fenton, Ph.D., published three important papers in the October issue of the journal Toxicologic Pathology. “The goal of these papers is to increase the ability of other scientists to produce excellent mammary specimens in their research,” Fenton said. “We are also providing data for study design and translation, so that results can be compared across labs and across the globe.”
- A project led by Jason Stanko, Ph.D., a biologist in Fenton’s group, pinpoints differences in the timing of mammary gland development among strains of rodents commonly used to study chemicals that may trigger tumors. With this new information, researchers can test the chemicals at the most vulnerable point in development.
- Work by Adam Filgo, Ph.D., and collaborators at the University of North Carolina, Chapel Hill (UNC), NIEHS, and NTP filled gaps in scientific understanding of male and female mammary gland development, such as when particular hormone receptors develop. The new data, including detailed images, will assist researchers who study the effects of chemical exposures.
- UNC predoctoral fellow Dierdre Tucker and colleagues developed a reliable method for studying mammary glands that will help researchers correctly identify abnormal growths and reduce false negative findings. The new method will help scientists pinpoint environmental factors that lead to problems in mammary development or function.
Researchers funded by NIEHS continue to advance understanding of how breast cancer can get started. Below are just two examples.
- BCERP grantees at the University of California, San Francisco wanted to know more about the effects of three environmental chemicals suspected of affecting breast development — bisphenol A, mono-n-butyl phthalate, and polychlorinated biphenyl 153, or PCB. The team, led by Katherine Williams, Ph.D., studied how mouse mammary glands changed after exposure to the substances. They observed dramatic differences in the proteins present in the tissue, which could be associated with important changes in cell function.
- In another study, a team led by Amanda Henning and grantees at the University of Wisconsin studied genetic mechanisms during developmental periods, such as puberty and early life, that are particularly sensitive to environmental exposures. The result is a new model for studying how environmental factors combine with genetic factors and developmental stages to change breast cancer risk.
Filgo AJ, Foley JF, Puvanesarajah S, Borde AR, Midkiff BR, Reed CE, Chappell VA, Alexander LB, Borde PR, Troester MA, Bouknight SA, Fenton SE. 2016. Mammary gland evaluation in juvenile toxicity studies: temporal developmental patterns in the male and female Harlan Sprague-Dawley rat. Toxicol Pathol 44(7):1034−1058.
Henning AN, Haag JD, Smits BM, Gould MN. 2016. The non-coding mammary carcinoma susceptibility locus, Mcs5c, regulates Pappa expression via age-specific chromatin folding and allele-dependent DNA methylation. PLoS Genet 12(8):e1006261.
Stanko JP, Kissling GE, Chappell VA, Fenton SE. 2016. Differences in the rate of in situ mammary gland development and other developmental endpoints in three strains of female rat commonly used in mammary carcinogenesis studies: implications for timing of carcinogen exposure. Toxicol Pathol 44(7):1021−1033.
Tucker DK, Foley JF, Hayes-Bouknight SA, Fenton SE. 2016. Preparation of high-quality hematoxylin and eosin-stained sections from rodent mammary gland whole mounts for histopathologic review. Toxicol Pathol 44(7):1059−1064.
Williams KE, Lemieux GA, Hassis ME, Olshen AB, Fisher SJ, Werb Z. 2016. Quantitative proteomic analyses of mammary organoids reveals distinct signatures after exposure to environmental chemicals. Proc Natl Acad Sci U S A 113(10):E1343−1351.