Sisters share a lot more than secrets and laughter. They also share genes and at least some elements of lifestyle. Scientists already know that if a woman has breast cancer, her sister has a much higher chance of developing the disease, too. That's why NIEHS is kicking off the Sister Study, which hopes to glean more information about environmental causes of breast cancer in women who have a genetic risk for developing the disease.

In October, NIEHS launched a nationwide recruitment of 50,000 women who do not have breast cancer, but have a sister who has been diagnosed with the disease. The Sister Study is a long-term study that will follow the women for at least 10 years.

Researchers believe ingredients in many common products like gasoline, pesticides, paint remover, glue and plastic interfere in the role of hormones, possibly contributing to the development of breast cancer. But past studies have not been able to establish a strong link. Researchers in the Sister Study hope data gathered in this study will shed some light on the health effects of such exposure, combined with genetic and age-based risk factors.

As part of the study, researchers will collect information from study participants about their lifestyles, medical histories, jobs and environment. Members of the research team will also collect blood samples and specimens of urine, toenails and house dust. The women in the study will complete questionnaires about their diet, family history and environmental exposures.

The study was recently featured in most of the major newspaper, television and radio outlets in the United States.

Women are eligible to participate if they are between 35 and 74 years old, live in the United States and have a sister related by blood who has been diagnosed with breast cancer. Women unable to enroll in the study can still help by volunteering or by spreading the word about the study. For more information or to join, call 1-877-474-7837 or visit www.sisterstudy.org.