BRCA1 and BRCA2 are human genes that belong to a class of genes known as tumor suppressors. Mutations in these genes have been linked to a higher risk of breast cancer and ovarian cancer.
A woman's lifetime risk of developing breast or ovarian cancer is greatly increased if she inherits a harmful mutation in BRCA1 or BRCA2. Cancer is also more likely to develop at an earlier age. Women with a BRCA1 or BRCA2 mutation have a 60% risk of developing breast cancer in their lifetime (compared to 12.5% in the general population) and a 15-40% chance of developing ovarian cancer in their lifetime (compared to 1.4% in the general population).
A genetic counselor can help you understand if you're likely to have an inherited susceptibility to breast or ovarian cancer. Those most appropriate for genetic testing have:
- High numbers of family members with cancer diagnoses throughout several generations, either maternal or paternal
- Family member diagnosed with cancer before age 50
- Family members who have been diagnosed with multiple cancers (for example, breast and ovarian)
- Male breast cancers, or clusterings of other cancers such as colon, prostate, stomach or pancreatic
A genetic test for the BRCA mutations involves a simple blood draw that can be done in your doctor's office. The blood is then sent to a special laboratory for analysis. Results are returned several weeks later. Genetic counseling is recommended before and after testing.
The cost for BRCA1 and BRCA2 mutation testing usually ranges from several hundred to several thousand dollars. Insurance policies vary as to whether the cost of testing is covered. People who are considering BRCA1 and BRCA2 mutation testing may want to find out about their insurance company's policies regarding genetic tests.
A positive test for a deleterious mutation means the person has inherited a genetic mutation on the BRCA1 or BRCA2 gene. This means a higher risk of developing breast or ovarian cancer. It does not mean that person WILL develop cancer.
A negative test means there is not an inherited genetic mutation in the BRCA genes. This does not mean the person will NOT develop cancer. Not all genes involved with cancer are known, and the majority of cancers are sporadic, or random.
There is a third possible result, a mutation of uncertain significance (also called a variant of uncertain significance or VUS). This means that the BRCA1 or BRCA2 gene is not normal, but it is not clear if the specific gene mutation is associated with a higher risk of breast and ovarian cancer. Approximately 7% of test results come back as VUS. It is very important to discuss these (and all) BRCA test results with a health professional who is knowledgeable about BRCA testing.
You have several options to manage your cancer risk.
Surveillance: Begin cancer screenings at an earlier age, including mammography and breast MRI.
Surgery: Women typically have their ovaries removed, which reduces the risk of both breast and ovarian cancer. Timing of ovarian removal is important, and should take into consideration both family planning and the usual age at which ovarian cancer develops in those with BRCA gene mutations. Women may also choose to have their breasts removed.
Medication: Two drugs have been shown to decrease the risk of breast cancer: tamoxifen and raloxifene. Both are taken as a daily pill.
Risk avoidance: Certain lifestyle behaviors have been linked to cancer risk, including diet, alcohol consumption and physical activity.
Talk to your doctor about the options that are best for you.
In 2008, the U.S. Congress passed a law, Genetic Information Nondescrimination Act, or GINA, to protect citizens against health insurance or employment discrimination based on their genetic information. The law says health insurance companies cannot raise premiums or claim a pre-existing condition based only on genetic testing results. Likewise, employers cannot make hiring, firing or salary decisions based on a person's genetic information.
Breast Cancer Genetics a U-M Web site designed to educate about BRCA testing options