Knowing The Genes That Affect Breast Cancer?
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If you have a family history of breast cancer, you may be wondering what your chances are of inheriting the condition.
Thanks to genetic research, this is a much easier question to answer. Mutations in two genes — BRCA1 and BRCA2 — have been identified as a primary genetic cause of breast cancer.
Not everyone who gets breast cancer inherits it through their family history. And not everyone with mutations in their BRCA1 or BRCA2 genes will develop breast cancer. But having these specific mutations does greatly increase your risk of developing breast cancer during your lifetime.
Let’s take a look at how these genetic mutations contribute to cancer, how you can find out if you have these mutations, and who’s a good candidate for genetic testing.
How do certain genes affect breast cancer?
Cancer is a health condition that can be caused by changes to your genes. Your genes carry instructions that tell the proteins in your cells how to behave.
When your genes cause proteins and cells to develop in abnormal ways, it can become cancer. This can happen because of a gene mutation.
It’s possible to be born with certain gene mutations. This is called an inherited mutation. Somewhere between 5 to 10 percent of breast cancers are currently thought to be hereditary. Your genes may also mutate later in life due to environmental or other factors.
A few specific mutations can play a role in developing breast cancer. Affected genes tend to be ones that control things like cell growth and the DNA in your reproductive organs and breast tissue.
BRCA genes and breast cancer
BRCA1 and BRCA2 genes typically make proteins that can repair your DNA when it gets damaged, particularly in your breasts and ovaries. When these genes are mutated, it can cause abnormal cell growth. These cells can then become cancerous.
About 50 out of every 100 women born with a BRCA gene mutation will develop breast cancer by the time they’re 70 years old, according to the Centers for Disease Control and Prevention (CDC). They also have an increased risk of developing other cancers, including:
- melanoma
- ovarian cancer
- colon cancer
- pancreatic cancer
People born with a penis and who have the BRCA2 mutation have an increased risk of developing male breast cancer.
Your risk for having BRCA1 or BRCA2 mutations may be higher if you have:
- multiple family members who have been diagnosed with breast cancer
- relatives who developed breast cancer before they were 50 years old
- any family members who were diagnosed with ovarian cancer
- any male relative who developed breast cancer
- anyone in your family who developed both breast and ovarian cancer
- someone in your family who has already been tested and found to carry a BRCA gene mutation
Other genes that can affect breast cancer
In addition to BRCA and BRCA2, there are other genes that can increase your risk of developing breast cancer if you inherit a mutation.
These genes include:
- CDH1. Mutations in CDH1 put you at a higher risk of developing hereditary diffuse stomach cancer (gastric cancer). This mutation also increases your risk of lobular breast cancer.
- PALB2. This gene partners with the BRCA gene in your body. People with mutations in the PALB2 gene are 9.47 times more likely to develop breast cancer than people who don’t have that mutation.
- PTEN. This is a gene that regulates cell growth. A PTEN mutation can cause Cowden syndrome, a condition that increases your risk of developing benign and cancerous tumors, like those found in breast cancer.
- TP53. Mutations in TP53 can lead to Li-Fraumeni syndrome, a condition that predisposes your body to several different types of cancer, including breast cancer and brain tumors.
Considerations for genetic testing
If you meet any of the criteria that increases your risk of having BRCA1 or BRCA2 mutations, as listed above, you may be considering genetic testing.
Genetic testing for BRCA1 or BRCA1 is usually a simple blood or saliva test. After a conversation and a prescription from a doctor, you’ll have a sample of your blood or saliva drawn and sent to a lab. The lab looks for the mutations, and the doctor will call you with the results.
You can also pay a direct-to-consumer company to do the test without a referral from your doctor. But these tests only test for BRCA1 and BRCA2 gene mutations. They can’t rule out any and all factors that could increase your risk of breast cancer.
If you’re curious about other genetic mutations that you may have, you’ll need to speak with a doctor about getting tested for those mutations, too.
The National Comprehensive Cancer Network offers criteria for who should consider getting a genetic test for BRCA1 and BRCA2 mutations, in addition to other gene mutations including those discussed above. Just know that insurance may not always cover genetic testing.
Currently, these tests aren’t seen as necessary or recommended for the general public. Genetic testing is only recommended if you have a family history of breast cancer or ovarian cancer.
Children under age 18 are not currently advised to get genetic testing for BRCA mutations. This is because there are no preventive measures that can be taken at that age and very little chance of children developing the types of cancers connected to these mutations.
The takeaway
BRCA1 and BRCA2 are known as the “breast cancer genes.” The genes themselves aren’t what increase your risk of breast cancer, because everyone has them. Mutations in the genes can produce an increased risk of breast cancer, ovarian cancer, and several other types of cancer.
For this reason, people with a family history of breast cancer are getting genetic testing to see if they have the mutation. Having the mutation doesn’t necessarily mean that you’ll develop breast cancer. Knowing your risk may make you feel more at ease, or it might make you anxious.
If you have a family history of breast cancer, speak with a doctor about the pros and cons about getting genetic testing for these mutations.
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