BRCA genes: what you should know
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By The Edith Sanford teamApril 9, 2014
We’ve all heard of the breast cancer genes, BRCA1 and BRCA2, but what are they, and what do they mean for you?
If you feel a little unclear on this subject, you’re not alone. So, recently, we asked Kristen De Berg, a certified genetic counselor here at Sanford Health, to help clarify some common BRCA questions.
Q: What are the BRCA genes?
KDB: The BRCA1 and BRCA2 genes are actually good genes. They’re tumor suppressor genes, so we really want them to function properly in our cells. When they aren’t working, they predispose an individual to breast and ovarian cancer.
Think of it this way…
We’re all born with two copies of every gene. Normally, we inherit one working copy of BRCA from our mom, and one working copy from our dad. As we age, something — like environmental exposure, or simply the aging process — may cause some kind of mutation that could make one of those genes stop working.
Because most of us start with two copies, we’re still okay because we have a backup to keep protecting us from cancer, but about five to ten percent of the population is born with one copy of the BRCA gene that’s already not working. These people only have one working copy. So, if a mutation develops as they age, they don’t have a backup to protect them.
Q: What’s the difference between BRCA1 and BRCA2?
KDB: We all have two copies of each of these genes. BRCA1 was just discovered before BRCA2.
BRCA1 and 2 mutations both increase the risk for breast cancer and ovarian cancer. The overall risk for breast and ovarian cancer is greater with BRCA1 than BRCA2.
BRCA2 mutations may also increase the risk for pancreatic cancer and melanoma in both men and women, and possibly prostate cancer in men.
Q: Are there other genes linked to breast cancer?
KDB: In addition to BRCA1 and 2, variations in the CDH1, PTEN, TP53 and STK11 genes can also increase your risk for developing breast cancer. Currently, there are as many as 24 genes thought to have some link to breast cancer.
Q: My mom has BRCA-positive breast cancer. What does that mean for me?
KDB: It means you have a 50/50 chance of inheriting that problematic BRCA gene.
Your mom gave you a gift by giving you the knowledge of what caused her breast cancer. Now you can start considering whether you want to have testing done so that you can best manage your own risk.
Q: What happens if I test positive?
KDB: If you test positive and you’ve never had breast cancer, we’ll increase surveillance. We advise women to start mammograms and breast MRIs every six months, and as early as age 25. A woman may also choose to forgo breast screening and decide to have the breast tissue removed. There is no “right” management plan, and this decision is left up to the patient.
We also recommend ovarian cancer screening, which isn’t typically done in the general population. This means ovarian ultrasounds and a blood test called a CA125 starting between age 30 and 35.
Q: Last year, the Supreme Court ruled that the BRCA genes can’t be patented. What has been the impact of that decision?
KDB: The patents on those genes meant that we could only go through one company to have the BRCA test done. The big problem with that was, with some insurance companies, you only have one chance for testing.
So, say we’re looking at a family with a lot of breast cancer, and maybe other cancers as well. We had to make a decision: Do we do pursue BRCA testing, or do we consider testing for other genes? Now, for better or worse, these companies have lost their patents, and it’s opened up the options we have for testing.
Rather than choosing between tests, we can choose a test that includes any number of the genes that we’re worried about, if we need to. We’re able to cast a larger net that could give us better results.
Kristen De Berg is a certified genetic counselor at Sanford Health who specializes in oncology and women’s health.
Learn more about risk factors for breast cancer.