BRCA-1 and BRCA-2 Tests
Also known as
BRACA
Formal Name
Breast Cancer Gene 1 and Breast Cancer Gene 2
Why get tested?
To assess the risk of developing breast or ovarian cancer associated with inheriting abnormalities in BRCA-1 or BRCA-2
When to get tested?
If you have a family history of breast cancer before the age of 50 or ovarian cancer at any age
Sample required
A blood sample drawn from a vein in the arm
The Test Sample
What is being tested?
BRCA-1 and BRCA-2 are two genes that are linked with hereditary breast and ovarian cancers. About 200,000 women are diagnosed with invasive breast cancer each year and about 23,000 with ovarian cancer (according to the American Cancer Society). Of these cancers, about 5% to 10% will be due to a mutation in one of the BRCA genes. Men can also inherit an increased risk of developing breast cancer, primarily from an alteration in the BRCA-2 gene.
Individuals with mutations in BRCA1 or BRCA2 have significantly elevated risks for breast cancer (up to 80% lifetime risk), ovarian cancer (up to 40% lifetime risk), bilateral breast cancer and other types of cancers. BRCA mutations are inherited and passed from generation to generation. One half of the time, they are passed from the father’s side of the family.
The DNA in white blood cells is used to detect mutations in the BRCA genes. While the gene products (proteins) of the BRCA genes act only in breast and ovarian tissue, the genes are present in every cell of the body and blood is the most easily accessible source of that DNA.
How is the sample collected for testing?
The test for BRCA mutations is done on a blood sample collected by needle from a vein in the arm. The test does not require surgical biopsy of breast or ovarian tissue.
The Test
How is it used?
The tests for BRCA-1 and BRCA-2 can tell you if you have mutations in either of these two genes that have been connected to the development of breast and ovarian cancer. Most people do not have a BRCA gene mutation (only about 1 in 800 people in the general population will have one) and the U.S. Preventive Services Task Force has recommended (September 2005) that BRCA genetic testing not be ordered as a screening test on women who do not have a strong family history of breast and/or ovarian cancer.
BRCA testing should be considered for those women who do have close relatives (male or female) who have been diagnosed with breast cancer and/or have female relatives with ovarian cancer. This is especially true if the cancer occurred at a relatively young age (prior to 50). A patient should also strongly consider testing if a BRCA mutation has been identified in another family member. It is recommended that patients be counseled by a health care provider knowledgeable in cancer genetics both pre and post testing.
Comprehensive analysis of both genes is typically performed for referred patients. In specific populations, such as those of Ashkenazi Jewish descent, testing may be targeted to diagnose only those mutations known to appear in that group of people. If a particular BRCA-1 or BRCA-2 mutation has been identified in a family member with breast and/or ovarian cancer, then that specific mutation should be tested for in other family members.
When is it ordered?
Individuals with a strong family history of breast cancer or ovarian cancer often want this test performed. The test results may be used to decide whether to take steps that may prevent breast or ovarian cancer from developing in the future. Because we don’t know how effective the options for prevention are, people who are considering taking this test should seek counseling by a knowledgeable health care professional. In this way, they can be sure of learning about and understanding the implications of the test result (see “Is there anything else I should know?” below).
What does the test result mean?
Since there are hundreds of possible mutations of BRCA genes, test results must be interpreted by taking into account a person’s family history. A genetic counselor/trained health care professional should explain the meaning of the results and explain treatment options for the individual to decrease risk and testing options for other family members. Counseling on genetics should be offered both before testing occurs and after receiving test results.
A negative result does not mean that you cannot or will not develop breast cancer. It only means that you are not at risk for developing hereditary breast cancer related to the BRCA mutations for which you were tested.
The presence of a BRCA mutation means that the affected person is at an increased risk for developing breast and/or ovarian cancer. However, even within a family with the same BRCA mutation, not everyone will develop cancer, and those that do may develop it at different times during their life. According to the Centers for Disease Control and Prevention, estimates of lifetime risk for breast cancer in those with BRCA-1 or BRCA-2 mutations can range from 36%-85% and estimates of ovarian cancer from 16% to 60%.
Is there anything else I should know?
Your test results may have implications for other family members. When one member of a family is tested for BRCA mutations, issues often arise about how or whether to share this information with other family members. Seek advice from a genetic counselor about communication of result with your family members.
Pre and post test consultation with a health care provider knowledgeable about genetic testing cannot be overemphasized. There are many issues to be considered when preparing for a genetic test and upon learning the results, and a genetic counselor has the knowledge and experience to help you sort through them.
Common Questions
If the BRCA test is positive, what are my options?
If the BRCA test is positive, the options include increased frequency of check-ups (e.g., mammography, blood tests for CA-125, or transvaginal ultrasonography); medications that could reduce risk (e.g., oral contraceptives or tamoxifen); or surgical removal of the ovaries or breasts. There are a number of variables involved and it is important to discuss your options with your doctor and genetic counselor.
If the BRCA test is negative, how likely/unlikely am I to get breast or ovarian cancer?
Research studies have reported that for every 1000 women negative for BRCA mutations, between 12 and 45 of them will develop breast cancer by age 50 and between 3 and 4 will develop ovarian cancer by age 50. The risk increases with age.
Where can I get this test?
The test can be ordered by a doctor, preferably by one who can also offer genetic counseling. The blood sample will be sent to a laboratory that specializes in BRCA testing. The American Society of Clinical Oncology and the National Breast Cancer Coalition encourage women seeking the test to participate in long-term outcome studies to help gather information on the effectiveness of different check-up and treatment options.
