Does exposure to certain pesticides increase the risk of breast cancer? Is there a link between childhood obesity and adult breast cancer? If human estrogen promotes some kinds of breast cancer, can phytoestrogens from plants possibly offer protection? These are some of the questions answered on the World Wide Web at http://www.cfe.cornell.edu/bcerf/. (Answers also can be found at the end of this news release.)

The site is a comprehensive source of science-based information on the relationships between breast cancer and environmental risk factors. Developed by the Cornell University Program on Breast Cancer and Environmental Risk Factors in New York State (BCERF), the newly enhanced site addresses the roles that pesticides, diet, lifestyle and genetics may play in breast cancer risk, and offers strategies to reduce the risk of breast cancer.

A recent revamping of the site makes the numerous resources easier to search and navigate, according to BCERF webmaster Marie Stewart. "We've also expanded the offerings on the site, including an on-line version of our newsletter, The Ribbon. We encourage browsers to add their names to our electronic mailing list," Stewart said.

Visitors are encouraged to provide feedback on the web site by sending e-mail to breastcancer@cornell.edu.

"We have one of the most comprehensive lists of references on breast cancer and the environment," says Suzanne M. Snedeker, BCERF research project leader. "This searchable Environmental Risk Factor Database of over 2,000 references is one of the many features on our web site. We also provide links to other breast cancer web sites with information on breast cancer screening, diagnosis, and networking."

Much of the information at the BCERF web site is in the form of easy-to-read fact sheets on such topics as alcohol and breast cancer risk, tumor suppressor genes, the biology of breast cancer and reducing pesticide exposure. Critical evaluations by BCERF scientific staff examine evidence from current research that specific pesticides or dietary factors affect breast cancer risk. Maps pinpoint regions of high, moderate and low breast cancer incidence in New York state.

"Of all the known and unknown risk factors for breast cancer, the environmental risk factors are the ones over which we have some control," says June Fessenden MacDonald, BCERF director and associate professor of biochemistry, molecular and cell biology at Cornell. "By providing impartial, science-based information on environmental risk factors, we hope to help people make decisions that can have a positive effect on their health."

Research Coordinator Snedeker, an assistant professor of biological sciences at Cornell, together with Renu Gandhi, a BCERF research associate, report on relationships between pesticides and breast cancer risk. "Not only do we provide critiques of current research on specific pesticides and breast cancer risk," Gandhi says, " but we make recommendations for further needed research to policy makers and other scientists. We also translate these Critical Evaluations into fact sheets for the lay audience."

BCERF's on-line materials are developed for a diverse audience, ranging from consumers, educators and public policy makers to journalists and other scientists, according to Snedeker, who was a cancer biologist at the National Institute of Environmental Health Sciences before joining the Cornell program. Among other experts associated with BCERF are toxicologists, nutritional scientists, oncologists, epidemiologists, physicians and health educators.

Based in the Institute for Comparative and Environmental Toxicology in the Cornell Center for the Environment, BCERF involves faculty and staff members from the Cornell's colleges of Agriculture and Life Sciences, Arts and Sciences, Human Ecology, Veterinary Medicine; the divisions of Biological Sciences and Nutritional Sciences; Cornell Cooperative Extension; the Weill Medical College and Graduate School of Medical Sciences at Cornell; and the Strang Cancer Prevention Center. Funding support for BCERF comes from the U.S. Department of Agriculture, the New York State Department of Health and Cornell.

Answers to the initial questions, based on information from the web site <www.cfe.cornell.edu/bcerf/&gt; are:

• There is currently no demonstrated evidence that the weed killer 2,4-D, is a human breast carcinogen. However, as with any chemical, caution should be exercised in the herbicide's use, storage and disposal.
• Although there is no data to suggest that adolescent obesity is a risk factor for the development of breast cancer, overweight adolescents may be at greater risk later in life. They are more likely to be overweight as adults and it is harder for people to lose weight as they get older. Gaining weight and being overweight as an adult are considered risk factors for postmenopausal breast cancer.
• About two-thirds of all breast tumors have estrogen receptors and depend on human estrogens for growth. Phytoestrogens -- from soy-based foods and other legumes, as well as bean sprouts and seeds -- compete with human estrogens. However, phytoestrogens have only about 1/1000 the estrogenic activity of human estrogens. Thus, phytoestrogens can reduce overall estrogen activity by interfering with the activity of the stronger human estrogens in the body. Phytoestrogens also interfere with enzymes that promote cancer growth, while increasing hormones that restrict blood estrogen levels.