A new study that will look at 50,000 sisters of women diagnosed with breast cancer recently opened for enrollment across the US.

The Sister Study, conducted by the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health, will investigate environmental and genetic causes of breast cancer. The Sister Study is the largest study of its kind to look at breast cancer risk factors.

Women of all backgrounds and ethnic groups are eligible for the study if they are between the ages of 35 and 74; live in the US; have never had breast cancer themselves; and have a sister living or deceased who has had breast cancer.

To recruit a diverse group of volunteers and to ensure the results benefit all women, researchers are especially encouraging African-American, Latina, Native American, and Asian women, as well as women 60 and older, to join the Sister Study.

Experts Will Look at Sister's Environment

Sisters may be the key to unlocking breast cancer risk mysteries. Dr. Dale Sandler, chief of the Epidemiology Branch at NIEHS and principal investigator of the Sister Study says, "By studying sisters, who share the same genes, often had similar experiences and environments, and are at twice the risk of developing breast cancer, we have a better chance of learning what causes this disease.

"That is why joining the Sister Study is so important," Dr. Sandler says.

At the beginning, volunteers will complete several questionnaires and provide a sample of their blood, urine, toenails, and household dust.

"With that, we'll be able to look at how genes, activities of daily life, and exposure to different things in our environment are related to breast cancer risk, Dr. Sandler explains.

"We've made the process as easy and as convenient as possible, so we will come to you," she adds.

The landmark study will stay in touch with the volunteers for 10 years and compare those who develop breast cancer with the majority who do not.

While past studies have largely focused on hormones, reproductive health, and lifestyle, the Sister Study will take the most detailed look ever at how women's genes, and things women come in contact with at home, at work, and in the community may influence breast cancer risk.

Researchers will study a range of environmental exposures, from personal care and household products, to workplace and other common exposures.

"Genes are important, but they don't explain it all," says Dr. Sandler. "The truth is that only half of breast cancer cases can be attributed to known factors." And, two known genes linked to breast cancer, BRCA 1 and BRCA 2, play a role in only five percent to 10 percent of cases.

Women who may have felt helpless as they watched their sisters battle breast cancer now have an opportunity to help researchers learn more about causes of the disease.

Women Join the Study to Further Research

Dottie Sterling and Fluffy Reed both joined the study at the request of their youngest sister, Wish Martin, a breast cancer survivor in Maryland.

"Throughout my sister's fight with breast cancer, we all prayed and prayed for healing and a swift recovery," says Sterling, a Sister Study volunteer in Ohio. "Now my sister has been a breast cancer survivor for more than 13 years, and I could not be more proud. I see joining the Sister Study as my tribute to her strength and her faith."

Many women have lost their sisters to breast cancer.

"We need to find a cure for breast cancer and improve detection, diagnosis, and treatment," says Patricia Bango, a participant in Virginia. "I joined the Sister Study as an advocate for my sister, Sally, who did not survive this devastating disease. I know her hope would have been that these efforts will help researchers find out what causes breast cancer."

The Sister Study opened in pilot states, including Arizona, Florida, Illinois, Missouri, North Carolina, Ohio, Rhode Island, and Virginia, earlier in 2004, but is now open for nationwide enrollment.

Always consult your physician for more information.

Online Resources

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American Cancer Society

American Society for Clinical Oncology

Centers for Disease Control and Prevention (CDC)

National Cancer Institute

National Institutes of Health (NIH)

National Women's Health Information Center

Sister Study.Org

Susan G. Komen Breast Cancer Foundation

December 2004

Sister Study Open to Sisters of Women with Breast Cancer

Experts Will Look at Sister's Environment

Women Join the Study to Further Research

More on the Sister Study

Online Resources

More on the Sister Study

The Sister Study is the only long-term study in the US of women aged 35 to 74 who have sisters with breast cancer, according to the  National Institute of Environmental Health Sciences (NIEHS). The study will follow 50,000 women for at least 10 years and will collect information about genes, lifestyle, and environmental factors that may cause breast cancer.

What will the Sister Study tell us?

Researchers believe the Sister Study will help us better understand reasons women get breast cancer, especially reasons that concern genes and the environment. Results from the Sister Study may also help us understand reasons women get other diseases such as heart disease and other types of cancer.

Why is it important for me to help the Sister Study?

Breast cancer is a serious disease that will affect one in eight women in the US over their lifetimes. The NIEHS believes the Sister Study will give valuable information about the different reasons women get breast cancer. This information may help provide answers about ways to prevent breast cancer.

How can I help the Sister Study?

There are three ways women can help the Sister Study:

Who can join the Sister Study?

You can join the Sister Study if you:

Why aren't you studying women who have breast cancer?

The Sister Study collects information about genes and environmental exposures.

This information is collected before a woman's body has been changed by breast cancer, its treatment, or changes she might make in her lifestyle after being told she has breast cancer.

Researchers will be able to compare this information between women who do and do not get breast cancer in the future. By collecting this information before a woman develops breast cancer, researchers can better discover factors that may cause breast cancer.

What will you ask me to do if I join the Sister Study?

If you join the Sister Study, the NIEHS will ask you to:

Will my information be kept private and confidential?

Yes. All information you give will be kept private and confidential. The Sister Study will not share information that identifies you with others.

Always consult your physician for more information.