About 13% of women in the U.S. will get breast cancer during their lives. But some women have a much higher risk because of their genes. Breast cancer develops when normal cells start to grow abnormally and form a tumor.

Certain genes, including BRCA1 and BRCA2, help repair damaged DNA to keep cells from growing out of control. Everyone has these genes—they’re inherited from your parents. But some people inherit harmful changes (called mutations) in BRCA1 or BRCA2 genes, which prevent the genes from working properly.

An inherited BRCA1 or BRCA2 mutation raises your risk of developing breast cancer. In fact, more than 60% of women who inherit a BRCA1 or BRCA2 mutation will get breast cancer. BRCA1-related breast cancers are more likely to be triple-negative, a type that is harder to treat. And these gene mutations also increase the risk for other kinds of cancer, including ovarian, pancreatic and prostate cancers.

Who should consider genetic testing?

There are both rewards and risks that come with genetic testing. Before you get tested, talk through the pros and cons with a genetic counselor to help you make the decision.

Testing is often recommended if you have:

• A family history of breast or ovarian cancer.
• Ashkenazi or Eastern European Jewish ancestry.
• A personal history of breast cancer.
• A personal history of ovarian, fallopian tube or peritoneal cancer.
• A BRCA gene mutation in your family.

Testing can be done before or after a cancer diagnosis. It can help you reduce your risk or guide treatment decisions. Results can also alert family members to their own potential risk. The genetic counselor can help you make sense of your results and what they mean for your health.

Possible results include:

• Positive. A known harmful mutation is found.
• Negative. No harmful change is found.
• Uncertain. A gene change is found, but its impact is unclear.

A positive result means you have a higher risk of developing certain cancers, but it doesn’t mean you will definitely get cancer. And a negative result doesn’t rule out all risk. If your result is uncertain, your doctor may focus on other risk factors, like family history, to guide next steps.

Managing cancer risk

If you have a BRCA1 or BRCA2 mutation, you can lower your risk by starting breast cancer screening earlier. Other options include preventive medications and preventive surgeries to remove breast tissue. Talk to your provider about what’s right for you. If you’re concerned about your risk, ask your provider about genetic testing.

Sources: American College of Obstetricians and Gynecologists; Centers for Disease Control and Prevention; National Cancer Institute