BRCA-1 and BRCA-2
BRCA-1 and BRCA-2 are 2 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.
PREPARATION FOR TEST
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.
No genetic mutations.
Ranges for normal findings may vary among different laboratories and hospitals. You should always check with your doctor after having lab work or other tests done to discuss the meaning of your test results and whether your values are considered within normal limits.
MEANING OF TEST
Your caregiver will go over the test results with you and discuss the importance and meaning of your results, as well as treatment options and the need for additional tests if necessary.
OBTAINING THE TEST RESULTS
It is your responsibility to obtain your test results. Ask the lab or department performing the test when and how you will get your results.
OTHER THINGS TO 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.
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.
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.
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.