BRCA gene mutation testing is a type of genetic test that checks for mutations in BRCA1 and BRCA2 genes. Individuals who test positive for mutations in either of these genes that code for proteins called tumor suppressor genes are at higher risk of developing cancer of the breast and ovaries. Tumor suppressor genes help suppress the growth of cancer cells. When these genes are mutated or altered, this anti-cancer protection is lost. Most mutations in BRCA1 and BRCA2 genes are hereditary, meaning you got it from your father or mother. Mutations in one of these two genes account for 5 to 10% of all breast cancers and 15% of ovarian cancers.
Testing positive for a BRCA mutation doesn't mean you'll get breast or ovarian cancer, but it does significantly increase the odds. For example, one study showed that women with a BRCA1 mutation had a 72% lifetime risk of developing breast cancer and a 44% risk of being diagnosed with ovarian cancer. The odds are slightly lower if you test positive for a BRCA2 mutation. The lifetime risk of breast cancer with a BRCA2 mutation is 69% for breast and 17% for ovarian cancer. The chance of developing other forms of cancer is also slightly higher in those who have one of these mutations. For example, mutations in either gene seem to modestly increase the risk of developing cancer of the pancreas.
Because the odds of developing breast and ovarian cancer is substantially higher if you carry one of these gene mutations, experts recommend BRCA gene mutation testing for people who have risk factors. You should consider testing for BRCA1 and BRCA2 mutations if you have:
A personal history of ovarian cancer
A personal history of breast cancer before the age of 50
A personal history of breast cancer in both breasts
A personal history of triple negative breast cancer diagnosed before age 60
A personal history of breast cancer as well as a relative with ovarian cancer, two or more relatives with breast cancer or cancer of the pancreas, or a relative diagnosed with breast cancer at age 50 or younger.
Two or more relatives who were diagnosed with breast cancer before age 50
A family member with bilateral breast cancer or a history of both ovarian and breast cancers
A family member with ovarian cancer ⢠A relative believed to have a BRCA1 or BRCA2 mutation
A male family member with breast cancer
Ashkenazi Jewish ancestry
BRCA gene mutation testing is usually carried out through a blood test, but there is a form of BRCA testing that uses cells collected from inside your mouth. Once harvested, the samples are sent to a special lab for analysis. It may take up to a month to get the results back. If the results are positive, you'll want to discuss the results with your physician.
Certain medications, particularly an estrogen-blocking medication called Tamoxifen, can lower the risk of developing breast cancer if you're at high risk or if you have a BRCA gene mutation. Another drug called raloxifene, a medication used to treat osteoporosis, also reduces the risk of developing breast cancer in women who are at high risk.
Because these medications have side effects, you wouldn't take them for breast cancer reduction unless you're at significantly higher risk. It's not clear whether lifestyle factors greatly impact on the risk of developing breast or ovarian cancer when you have a BRCA mutation. Future studies will likely look at this issue. However, a pregnancy early in life and breastfeeding seems to modestly protect against breast cancer. Pregnancy also lowers the risk of developing ovarian cancer. Oral contraceptive pills and hormone replacement therapy may boost the odds of developing breast cancer, but oral contraceptives actually lower the risk of ovarian cancer.
Knowing that you have mutations that increase your risk of developing breast and ovarian cancer may impact how often your physician recommends screening for the diseases. If you're at high risk, your physician may recommend screening for breast cancer at an earlier age and screening more often. Some women even opt for preventative surgery by having their breasts and/or ovaries removed.
The results of BRCA gene testing also provides valuable information for other family members. If you're positive for a BRCA1 or BRCA2, close family members should also consider genetic testing.
Up-to-Date (for Clinicians) "Prevalence of BRCA1 and BRCA2 mutations and associated cancer risks" Lab Tests Online. "BRCA Gene Mutation Testing" National Cancer Institute. "BRCA Mutations: Cancer Risk and Genetic Testing"
What is BRCA gene testing, and what can it tell you about your risk of developing breast or ovarian cancer? This article discusses how the test is performed, who should get tested, what the results mean, and why you should get tested if you have certain risk factors.