The Sister Study, a national study that is examining the impact environment and genes may have in getting breast cancer, is nearing its goal of getting 5,000 black women to participate, but more are needed.

The study needs 50,000 women by the end of the year before research can begin, and researchers want at least 5,000 black women to participate to make the study statistically relevant. As of last week, more than 3,600 black women had signed up, according to Carrissa Dixon, a recruiter for the effort.

“It’s really going great,” Dixon told BlackAmericaWeb.com, adding that about 1,700 black women have signed up since hearing about the study on the "Tom Joyner Morning Show."

“The power of urban radio has definitely been proven in this study,” Dixon said.

Black women are less likely than white women to get breast cancer, but when they do, they are more likely to die -- especially women under 50 years of age.

A study published last June in the Journal of the American Medical Association reported black women under the age of 50 have a 77 percent higher mortality rate from breast cancer than other women of the same age.

The study, led by scientists at the University of North Carolina at Chapel Hill schools of Public Health and Medicine and the UNC Lineberger Comprehensive Cancer Center, said that younger, pre-menopausal black women are more prone to an especially aggressive type of cancer.

According to the American Cancer Society booklet, Cancer Facts: Seven Figures for African-Americans 2007-2008, “Factors that contribute to the higher death rates among African-American women include differences in access to and utilization of early detection and treatment, risk factors that are differentially distributed by race or socio-economic status, or biological differences associated with race.”

But it’s not just a matter of access to health care. Even after accounting for income and access to strong health care, “Poorer outcomes among African-American women persist. ... There is also evidence that aggressive tumor characteristics are more common in African-American women than white women.”

Dixon said without data on black women, researchers won’t be able to determine why black women are disproportionately affected at a younger age and why their mortality rate is higher.

“We know there are a lot more women out there who are eligible who have not responded,” Dixon said. “We’re all caught up in the concept of breast cancer research, doing all the walks and the shopping to raise money, but research is not research without data. We've just got tp get further. It’s not enough to write a check to breast cancer. The researchers can’t do anything with that money without data.”

Researchers are looking for women in the U.S. and Puerto Rico, ages 35 to 74, who never have had breast cancer but have a sister who has. The study seeks women from all races, ethnicities, geographic locations, occupations and socio-economic backgrounds.

The study requires participants to answer a questionnaire, provide urine, blood, hair and nail samples, as well as dust samples from home.

Over the 10-year course of the study, researchers will check in periodically to monitor changes in participants’ health, lifestyle and occupation. All personal information is kept confidential.

The Sister Study is not a clinical trial. Participants will not be asked to make changes in their daily lives; there are no test results.

Dixon said the researchers have committed to waiting until they get the numbers of minority women needed for the study, although the deadline for getting 50,000 women signed up is at the end of the year.

“We will probably reach 50,000 before we get the 5,000,” Dixon said. “We’re not going to stop at 50,000. We’re committed to go beyond the 50,000 through the middle of next year, if necessary,” to ensure at least 5,000 black women participate.

To sign up for the Sister Study, visit www.sisterstudy.org or call the hotline from 9 am to 9 pm ET, toll-free at 1-877-4-SISTER.