Researchers say sisters of women who have had breast cancer have about twice the risk of developing the disease themselves. That's why a new study is focusing on that group.

Doctors are recruiting women all over the country to take a different approach to find what may be causing breast cancer.

News on 6 reporter Heather Lewin explains why sisters may hold the key and why minorities especially need to be involved.

Wanda Willis: "calling my sister was hard because we lost our mom from cancer at an early age." Wanda’s sister Tina Hall: "It was like here we go again. My mom was diagnosed and very quickly deteriorated healthwise. And so I was very concerned about my sister, what she would need as far as treatment, what I would need to do to support her through this."

With fears for her own health and others' Tina Hall signed up for the Sister Study. The goal is to recruit 50,000 women, all cancer-free sisters of those who've been diagnosed with the disease.

Researchers say most breast cancer studies have focused on hormones, reproductive health and lifestyle. What's different about this project is it studies genetics and the environment. Sister Study director Dr Dale Sandler: "We actually know very little about environmental factors that may influence breast cancer risk and we've seen that breast cancer rates have changed over time, the rates change from place to place and all of this suggests that environmental factors play a role."

Doctors say because sisters share DNA, common experiences and exposure to their surroundings, comparing their information will make it easier to find links between breast cancer and genes or the environment.

There's another reason Tina Hall is an important candidate. Dr Dale Sandler: "Generally women from underserved populations, minority populations have not participated in research studies." Tina Hall: "When we go to get treated we're going off information that's been collected from a different population. So we need to know how it affects African-American women and what treatements are effective with us."

Participants complete an online questionaire or phone interview, then every year for the next deacde will submit blood and other samples for study.

Doctors hope to include every state. With about 2,900 Oklahoma women developing breast cancer every year, Green Country residents could help be part of the cure.

Doctors are looking for women ages 35-74. You do not have to take medication and a nurse will visit your home once a year for the samples.

So far, 150 Oklahomans have signed up. For more information, you can check out the Sister Study
or call 1-877-4-SISTER.