The BRCA gene made headline news across the world in 2013 when Angelina Jolie wrote about her positive test for the mutation, and the breast surgery that followed.
But how many of us know the facts about the genetic mutation she inherited, and what it means for your cancer risk?
We talked to Rachel Webster, genetic counselor in the department of Clinical Cancer Genetics. Here she addresses some common myths about BRCA.
Myth 1: The BRCA gene causes cancer
Everyone has BRCA1 and BRCA2 genes. They are genes that normally work to protect us from cancer. They repair damaged DNA and keep cells healthy. Genetic testing is done to uncover problems called mutations in the genes, which can stop them protecting us as they should. “Everyone has the same 20,000 genes,” says Webster. “We test to see if they work correctly.”
Myth 2: BRCA gene mutations are linked to breast cancer only
A positive BRCA mutation test does have the most serious impact on a woman’s risk for breast cancer but is also increases the risk for other cancers. For women, the likelihood of being diagnosed with breast cancer at some point during their lifetime moves from 12% to up to 87% after a positive test. A woman’s risk of ovarian cancer moves from 1-2% up to 44% after a positive test. A genetic counselor may also mention risks for pancreatic cancer and melanoma.
Myth 3: BRCA mutations only affect women.
Men can also test positive for BRCA mutations. A positive result means they are at increased risk for breast and other cancers like prostate, pancreas and melanoma. The risks remain relatively small but are higher than the general population. BRCA positive men may need regular breast exams given by their primary care physician and should talk with their care team about prostate cancer screening.
Another point to note is that BRCA gene mutations are not the only ones that can increase our risk of developing cancer. Mutations can happen with other genes too. “BRCA is the most well-known because of Angelina Jolie, but there are many other genes we could test for mutations,” Webster says. “All these gene mutations have different implications for our cancer risk and might involve a different treatment plan.”
Myth 4: A BRCA gene mutation will mean you need breast surgery
For BRCA-positive women, breast screening via MRI should start at age 25. At age 30, an MRI and mammogram should be done each year. Your doctor will talk with you about the pros and cons of having a double mastectomy, which is the removal of both breasts. Your doctor may also recommend you have your ovaries and fallopian tubes removed. This is because ovarian cancer is hard to detect in the early stages when it would be easier to treat. If you do decide to move forward, surgery can be planned around life goals like having children.
Myth 5: A BRCA gene mutation is inherited from your mother
Gene mutations can be inherited from any relative in your family, including the men. The chances of a gene mutation passing from a parent or sibling is 50%. With each step away from your immediate family the risk reduces by half. For example, if your grandmother has a BRCA gene mutation, your risk of inheriting it is 25%. If your first cousin has one, your risk is 12.5%.
Myth 6: Everyone should get a genetic test
If you want to know your genetic risk for cancer, the best place to start is your family history. If you have two or more close family members with the same type of cancer, or the same type of cancer in several generations of your family, talk to a genetic counselor. If you already have a cancer diagnosis, genetic testing may be recommended if you have two or more separate cancers, your cancer is very rare or you were diagnosed at an earlier age than usual. If you are from Ashkenazi (Eastern or Central European) Jewish ancestry and have a family history of breast and ovarian cancer, you may also benefit from genetic testing.
“Only about 5-10% of cancers are hereditary, so 95% of the time we’re still asking, how did this person develop cancer?” Webster says. “But if you are concerned, make an appointment to talk with a genetic counselor. Genetic testing has become more affordable, especially if you do have a family history of cancer.”