With the help of a $12 million grant, the National Institutes of Health are setting out to find the so far elusive answer to a complicated question: Why are black women in the United Stated so much more likely to die of breast cancer than their non-black counterparts?

Improving overall breast cancer survival rates haven’t applied to black women, the NIH said. According to a study in the journal Cancer Epidemiology, black women with breast cancer are about 70 percent more likely to die from the disease than white women with breast cancer. The rate of African-American breast cancer deaths in Memphis is double that of white breast cancer deaths.

According to the American Cancer Society, black women contract breast cancer just as often as white women, at 135 per 100,000 women. (Before October 2015, black women were less likely to have breast cancer.)

The grant will allow the NIH’s National Cancer Institute to study information from 20,000 black women with breast cancer, taken from 18 previous studies. Researchers will examine the genetic markers related to the women’s cancer and see what effect possible differences in detection or treatment between the two populations have on black women’s low breast cancer survival rates.

So far, experts speculate that the doubly higher incidence of the deadly triple-negative subtype of breast cancer in black women can help explain their higher death rates. But the NIH said it will also be looking at “genetic, environmental and social factors, including access to health care,” when studying the differences.

Study participants will have their entire genomes compared with other black women who do not have breast cancer and white women who do have breast cancer.

NCI’s acting director Douglas R. Lowy, MD said the study would aim to improve understanding of racial disparities in healthcare and knowledge of cancer in general.

“This effort is about making sure that all Americans—no matter their background—reap the same benefits from the promising advances of precision medicine,” he said in statement.

One doctor involved in the study told the New York Times it would be the first of its kind.