- Genetic testing for mutations in the so-called breast cancer genes BRCA1 and BRCA2 can not reveal much about the cancer risk than previous reports have estimated, according to two studies published in tomorrow New England Journal of Medicine . The researchers report that women with the mutation are more likely to develop breast and other cancers such as thought, and that mutations can also be less common in women with a family history of breast cancer. The results reinforce the idea that it is too early to implement widespread testing for mutations, say experts, who warn against radical answers - as mastectomies - for women who test positive. "We do not yet know enough to translate the results of testing in routine care patients," medical school dean Bernadine Healy Ohio State University, former director of the National Institutes of Health.
to find BRCA mutations - which are rare - most studies have focused on families with very high rates of breast cancer and other cancers in young family members however. this sample tends to overestimate the risk of cancer for women in general, said epidemiologist Jeffrey Struewing of the National cancer Institute So he and his colleagues recruited a population. - more than 5000 people in the Ashkenazi Jewish population and around Washington, DC .-- regardless of personal or family history of the disease. (Mutations in BRCA1 and BRCA2 are over 10 times more prevalent in the Ashkenazi Jewish community than in the general population, allowing Struewing use fewer participants to obtain a statistically significant pool. )
Only 2.4% of the sample had the mutation, a level consistent with previous studies. These carriers have been found to have only a 56% chance of developing breast cancer at age 70, compared to a figure of 87% in previous studies. For ovarian cancer, the group found a risk of 16%, compared to previous estimates that ran as high as 64%. And even the new estimates may be too high, Struewing said, because people may have been more likely to volunteer for the trial if they or a family member has had breast cancer.
Another study, conducted by Barbara Weber and his colleagues at the University of Pennsylvania, screened 263 patients with breast cancer to BRCA1 mutations and asked them their family history breast cancer and ovarian cancer. The researchers found that only 16% of women with a family history of breast cancer had BRCA1 mutations, compared to 45% found in previous studies. However, Weber said, that reduce the risk could lead to another problem -. A false sense of security among the family members of cancer patients without the mutation negative BRCA1 test is a project of own health law
Healy said the new findings dispel the idea that "if you have mutations in these genes, you have breast cancer." They stress the need to find and sort many other factors, she said, including several genes and environmental factors such Food and exposure to estrogen.
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