The BRCA1 gene, along with the BRCA2 gene, is often misunderstood. Though BRCA is an abbreviation for “breast cancer,” having these genes does not mean you’ll get cancer. In fact, these genes are present in every human. They normally play a huge role in suppressing tumors by repairing DNA and preventing tumors from growing out of control. The problem comes when the BRCA genes mutate.
Genetic mutations and breast cancer risks
For a variety of reasons, genes can sometimes become damaged or altered. Known as a genetic mutation, this can cause cascading effects throughout the body. In the case of the BRCA1 and BRCA2 genes, mutations can cause them to no longer suppress tumors, particularly in the breasts and ovaries.
Although genetic mutations can occur individually later in life, BRCA mutations are almost always inherited, or passed down through families. This means that if you have a relative with this type of genetic mutation, you are at greater risk for the same mutation.
Both mutations vastly increase the chances of breast cancer. According to the National Breast Cancer Foundation, about 12% of all women will develop breast cancer in their lifetime. But 45% of women with the BRCA2 mutation and a stunning 55-65% of women with the BRCA1 mutation will develop breast cancer before the age of 70.
Many of these are early-onset cancers, which occur before the woman turns 40. In addition, women with BRCA mutations are more likely to develop a second case of breast cancer after beating the first, as well as to have a very aggressive form of breast cancer known as triple-negative.
Are you at risk?
BRCA mutations are very rare, occurring only in about 0.25% of women. Therefore, genetic testing is not recommended for most women. However, certain risk factors make it more likely that you carry one of these mutations. According to the National Cancer Institute, these include:
- Family history of BRCA1 or BRCA2 mutation
- Personal or family history of breast cancer before age 50
- Personal or family history of certain other cancers, including ovarian, pancreatic, high-risk or metastatic prostate cancer, or male breast cancer
- Ashkenazi Jewish descent
It’s important to note that not everyone with these risk factors has a BRCA mutation. And not everyone with a BRCA mutation will develop breast cancer since the risks are undeniable in people who do have the mutation, though many women with one or more risk factors choose to undergo genetic testing.
Genetic testing for BRCA mutations
The test itself is easy, requiring a single blood draw. But testing for BRCA mutations is far from simple. For example, there are home tests that screen for three different mutations most common in people of Ashkenazi Jewish descent; however, these tests do not screen for hundreds of other potential variants. The National Cancer Institute notes that they can miss about 80% of possible cancer-causing mutations.
In addition, genetics as a whole is a highly complex field. Exactly what to test for, and what the implications of a positive result may be, can vary widely for each individual. Therefore, if you want to get tested, it’s best to do so in consultation with both your doctor and a genetic counselor.
Understanding genetic counseling
Genetic counseling works best when it occurs regularly throughout the testing process. Your genetic counselor can help you understand:
- Your personal risk profile
- The risks and benefits of testing, including potential psychological impacts
- The potential medical impacts of a positive, negative, or even uncertain result
- What a positive result could mean for your children and other close relatives
- Exactly which test would be appropriate for you, as well as technical details about that test and its interpretation
What do the results mean for me?
It’s crucial to talk to your genetic counselor once your results are in, as you’ll need their expert guidance on exactly what your results mean and the next steps you should consider. In general, though, there are three basic categories of test results for BRCA1 and BRCA2 mutations:
- This result means that you do have a genetic mutation associated with increased cancer risk. It does not necessarily mean that you will develop cancer, but you and your doctor should work together to lower your risk as much as possible.
- This means that you do not have any of the mutations for which you were tested. It’s known as a true negative if you have a family history of BRCA mutation, and you test negative for the variant that runs in your family. However, if you have a family history of cancer but no known genetic changes, your result may be considered an uninformative negative. This means there could still be a genetic mutation that hasn’t revealed itself yet, and additional follow-up care may be indicated.
- Variant of uncertain significance (VUS). This is a tough result for many people, but it isn’t uncommon. It means that the test detected a genetic mutation, but there is not yet enough scientific research into that mutation to know if it increases cancer risk. Most often, a VUS is reclassified as benign after more research, but it’s best to keep up with emerging information over time.
Mutations in the BRCA1 and BRCA2 genes are extremely rare, and they cannot definitively predict breast or other types of cancer. But they can increase the risks by a large margin, so it’s essential to learn your family history and make an informed decision on whether to seek genetic testing. Your doctor, in tandem with a genetic counselor, can help you determine if this is the right path for you.