BRCA1 and BRCA2: Cancer Risk and Genetic Testing

may not know their family history. If a woman with an unknown family history has an early-onset breast cancer or ovarian cancer, it may be reasonable for her to consider genetic testing for a BRCA1 or BRCA2 mutation. Women with an unknown family history and who do not have an early-onset cancer, even if they think they have an Ashkenazi Jewish background, are at very low risk of having a harmful BRCA1 or BRCA2 mutation and are unlikely to benefit from genetic testing.

Professional societies do not recommend that children, even those with a family history suggestive of a BRCA1 or BRCA2 mutation, undergo genetic testing. This is because no risk-reduction strategies for children exist, and their risk of developing a cancer type associated with a BRCA1 or BRCA2 mutation is extremely low. After they become adults, however, they may want to obtain genetic counseling about whether or not to undergoing genetic testing.

Should people considering genetic testing for BRCA1 and BRCA2 mutations talk with a genetic counselor?

Genetic counseling is generally recommended before and after any genetic test for an inherited cancer syndrome. This counseling should be performed by a health care professional who is experienced in cancer genetics. Genetic counseling usually covers many aspects of the testing process, including:

A hereditary cancer risk assessment based on an individual’s personal and family medical historyDiscussion of: The appropriateness of genetic testingThe medical implications of a positive or a negative test resultThe possibility that a test result might not be informative (see Question 12)The psychological risks and benefits of genetic test resultsThe risk of passing a mutation to childrenExplanation of the specific test(s) that might be used and the technical accuracy of the test(s)

How much does BRCA1 and BRCA2 mutation testing cost?

The cost for BRCA1 and BRCA2 mutation testing usually ranges from several hundred to several thousand dollars. Insurance policies vary with regard to whether or not the cost is covered. People considering BRCA1 and BRCA2 mutation testing may want to find out about their insurance coverage for genetic tests before having the test.

Some of the genetic testing companies that offer testing for BRCA1 and BRCA2 mutations may offer testing at no charge to patients who lack insurance and meet specific financial and medical criteria.

What does a positive BRCA1 or BRCA2 genetic test result mean?

BRCA1 and BRCA2 gene mutation testing can give several possible results: a positive result, a negative result, or an ambiguous or uncertain result.

A positive test result indicates that a person has inherited a known harmful mutation in BRCA1 or BRCA2 and, therefore, has an increased risk of developing certain cancers. However, a positive test result cannot tell whether an individual will actually develop cancer or when. Many women who inherit a harmful BRCA1 or BRCA2 mutation will never develop breast or ovarian cancer.

A positive genetic test result may also have important health and social implications for family members (see Question 15), including future generations. Unlike most other medical tests, genetic tests can reveal information not only about the person being tested but also about that person’s relatives:

Both men and women who inherit harmful BRCA1 or BRCA2 mutations, whether or not they develop cancer themselves, may pass the mutations on to their sons and daughters. Each child has a 50 percent chance of inheriting a parent’s mutation.If a person learns that he or she has inherited a harmful BRCA1 or BRCA2 mutation, this will mean that each of his or her siblings has a 50 percent chance of having inherited the mutation as well.

What does a negative BRCA1 or BRCA2 test result mean?

A negative test result can be more difficult to understand than a positive result because what the result means depends in part on an individual’s family history of cancer.

If a close (first- or second-degree) relative of the tested person is known to carry a harmful BRCA1 or BRCA2 mutation, a negative test result is clear: it means that person does not carry the harmful mutation and cannot pass it on to their children. Such a test result is called a