The BRCA1 and BRCA2 mutations are the most common genetic abnormalities associated with an increased risk of breast cancer. Women with BRCA1 mutations have a 33 to 50 percent risk of breast cancer by age 50 (compared with 2 percent among women in the general population), and a 56 to 87 percent risk of breast cancer by age 70 (compared with about 7 percent among all women). BRCA2 mutations are associated with a substantial, but somewhat smaller, risk of breast cancer in women.
Women with BRCA mutations also have a 27 to 44 percent risk of cancer of the ovaries or Fallopian tubes (the tubes that carry eggs from the ovaries to the uterus), compared with a risk of less than 2 percent among all women.
These mutations are most common among Ashkenazi (eastern European) Jews, but women from other ethnic and racial groups must recognize that they too could have BRCA mutations. Thus, a recent report in the Journal of the American Medical Association found that the prevalence of BRCA1 mutations was, for example, 3.5 percent in Hispanics, 2.2 percent in non-Hispanic whites, and 1.3 percent in African Americans. The prevalence was lowest (0.5 percent) among Asian Americans.
Talk to your doctor about screening for a BRCA mutation if you have any of the following factors that increase your risk:
- 2 or more first- or second-degree relatives with breast or ovarian cancer
- a close relative with breast cancer before age 50
- a family history of both breast and ovarian cancer
- male relatives with breast cancer
Genetic testing for BRCA mutations can be highly accurate—a positive test indicates a mutation with almost 100 percent certainty, while a woman with a negative test can be about 85 percent certain that no mutation is present.
Although the cost of tests for BRCA mutations can be as low as $400, only the Myriad Genetic Laboratories—the company that has patented the test for the BRCA genes—can carry out a full sequencing of BRCA1 and BRCA2 genes, at a cost of about $3,200. Insurance companies are more likely to cover all or part of the costs if your doctor provides compelling reasons for having the tests done.
You should consider speaking with a genetics counselor, both before getting a test for BRCA mutations and after your test results return.
