How genetics and BRCA genes affect your breast cancer risk
April 28, 2026Categories: Cancer Care, Women's Health
Overview: Learn how genetics and BRCA1/BRCA2 mutations affect breast cancer risk, who should consider genetic testing and prevention options.Your breast cancer risk is impacted by a variety of different factors – age, reproductive history, overall health. But genetics play an important role too.
Your breast cancer risk is influenced by a variety of factors – age, reproductive history and overall health. But genetics can also play a role in your cancer risk. About 5 to 10% of breast cancers and 10 to 15% of ovarian cancers are hereditary, according to the Centers for Disease Control and Prevention (CDC). This means cancer may run in your family. What it means to be a BRCA1 or BRCA2 carrier
If breast cancer, ovarian cancer or certain other cancers are common in your family, you may carry a mutation in the BRCA1 or BRCA2 gene. These inherited mutations increase the risk of developing breast and ovarian cancer, as well as other cancers such as pancreatic cancer, prostate cancer (in men) and melanoma.
Normally, BRCA1 and BRCA2 genes help protect the body by repairing DNA damage and preventing cancer from developing. However, when these genes are mutated, they don’t function properly and can significantly increase a person’s lifetime risk of breast and ovarian cancer.
What's the difference between BRCA1 and BRCA2?
While both genes serve similar functions, there are key differences.
| BRCA1 gene | BRCA2 gene |
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How common is the BRCA1 or BRCA2 mutation?
About one in every 500 women in the United States has a mutation in either the BRCA1 or BRCA2 gene, according to the CDC. About 60% of women with this genetic mutation will develop cancer.
You’re at higher risk of having the mutation if you:
- Are of Ashkenazi Jewish heritage.
- Have a male relative with breast cancer.
- Have a relative diagnosed with breast cancer before the age of 50.
- Have a relative with bilateral breast cancer (cancer in both breasts) or breast cancer and ovarian cancer.
If you’re at a higher risk of carrying the mutation, you’re likely a candidate for genetic testing.
Genetic testing for the BRCA gene mutation
Genetic testing involves the collection of a blood or saliva sample, which is then sent to a lab for analysis. The lab examines the sample for genetic mutations, and you may receive one of the following results:
- Positive: A known harmful BRCA mutation was found.
- Negative: No known harmful mutation was found.
- Uncertain (VUS): A change was found, but it's unknown if it increases cancer risk.
Learn more about genetic testing at MercyOne
What happens after learning you're a BRCA carrier?
Discovering you have the BRCA gene mutation can be overwhelming. But you have options when it comes to mitigating your cancer risk, including increased screenings, medication and surgery.
Annual screenings
When it comes to your options, your doctor will primarily look at two factors – your age and if you plan on having children. Many people may want to hold off on big surgeries if they plan to have children. In those cases, it’s recommended to increase screenings.
This typically means having a mammogram and an MRI every year followed by a clinical breast exam. Frequent screenings increase the chance of detecting and treating cancer earlier.
Medication
Your doctor may recommend medication to help with your cancer risk. The drug Tamoxifen blocks estrogen and can help prevent women from developing some breast cancers. But it can cause issues for women trying to get pregnant. and it’s unable to treat triple-negative breast cancer, which can develop in BRCA1 patients.
Surgery
Prophylactic mastectomy, surgery to remove one or both breasts, is the most aggressive but most effective option as it reduces your risk of developing breast cancer by 90-95%.
Women in their 40s and 50s typically opt for the prophylactic mastectomy since many are done having children.
Whatever option you choose, your provider will walk you through your personalized care plan and ensure you’re on a path to reducing your cancer risk.
Your first step
An important first step in understanding your genetic cancer risk is having a conversation about cancer and your family history. Knowing whether cancer runs in the family helps you make informed decisions when it comes to genetic testing and reducing your cancer risk.
