Medical researchers have begun recruiting women for a unique effort to determine the causes of breast cancer - the "Sister Study." Researchers hope to eventually enroll 50,000 women volunteers nationally, ages 35 to 74, whose sisters have been diagnosed with breast cancer.

Sisters of women with breast cancer are known to be at greater risk of breast cancer - up to twice the risk of other women. By following these sisters for ten years, the researchers hope to find clues as to why.

Is it genes they shared? A common diet? Early menstruation? A household or environmental chemical? A gene-environment interaction? By means of simple tests and questionnaires, the researchers - from the National Institute of Environmental Health Sciences, a part of the federal National Institutes of Health - will look at these and other factors.

The volunteers themselves may gain no medical benefit from the research but, as one of the women involved has said, "Our daughters may."

"First-degree relatives, especially sisters, have up to two times the risk of developing breast cancer as the average woman," said Dale Sandler, Ph.D., one the principal investigators of the study.

She said they are also likely to be within the same age range and to have been exposed to many of the same environmental factors during early childhood and even later in life. They also share many of the same genes, including those that determine the way their bodies handle carcinogens or repairs DNA.

They also, Sandler said, share a common concern over the disease that makes them more likely to want to participate in the study and stay in the study for the ten or more years that it may take to get results.

Besides collecting biological and environmental samples - blood, urine, toenail clippings and household dust - from participants at the outset, Sister Study researchers will use questionnaires to gather a multitude of data about health histories, environmental exposures and lifestyles. This comprehensive approach will allow the researchers to study new ideas regarding breast cancer while taking into account or reassessing what is already known.

Beyond the initial samples and questionnaires, participants will answer a shorter questionnaire each year for the next 10 or so years. Because most diseases like breast cancer develop slowly over a long period of time, researchers want to collect information from women who are healthy today and follow them over time to learn who stays healthy and who doesn't.

To volunteer or learn more about the Sister Study, go to the website 'http://www.sisterstudy.org or call toll free 1-877-4SISTER (1-877-474-7837).

SOURCE:
National Institute of Environmental Health Sciences (http://www.niehs.nih.gov)