We don't quite know what to do with the information yet.
Genetic testing is still limited to participants in clinical research.
Women who test positive for the mutation cannot turn to any proven therapy to prevent the disease. Testing positive for the mutation doesn't actually predict the likelihood that a woman will develop breast cancer if she has no family history of it. Despite these factors, researchers say the findings are important because they may lead to an understanding of what goes wrong inside a cell when it becomes cancerous. The study's results, published in the October issue of the journal Nature Genetics, show that one in 100 Ashkenazi Jews in the United States has a particular genetic mutation that may predispose them to breast or ovarian cancer. Researchers suspect the mutation might account for up to 16 percent of breast cancer and 39 percent of ovarian cancer in Ashkenazi women under age 50.