Test Results for BRCA1, BRCA2, and Other Gene Mutations
If you decide to get genetic testing, just a heads up: The results can be hard to understand on your own. This is why it’s so important to have a genetic counselor or doctor go over the results with you and discuss what they mean in the context of your personal and family history.
Once your blood, saliva, or other sample is sent to the lab, it usually takes between two and four weeks to get the results back. The results are sent to the doctor or genetic counselor who ordered the test.
In general, genetic test results tell you if you're positive or negative for a genetic mutation linked to breast cancer or potentially other cancers. Testing may also detect what’s called a “variant of uncertain or unknown significance.”
Testing positive for a BRCA or other gene mutation
There are multiple genetic mutations known to increase the risk of breast cancer. Two of the most well-known genes associated with breast cancer are the BRCA1 and BRCA2 genes. The 2024 National Comprehensive Cancer Network (NCCN) breast cancer genetic testing guidelines say anyone diagnosed with breast cancer at age 50 or younger should have genetic testing for mutations in the BRCA1, BRCA2, CDH1, PALB2, STK11, and TP53 genes.
Women who test positive for a BRCA1 or BRCA2 gene mutation can have up to a 72% risk of being diagnosed with breast cancer during their lifetimes. The average woman in the United States has about a 12% risk.
Women with a BRCA mutation also have a higher risk of developing ovarian and pancreatic cancers, as well as melanoma.
Men with a BRCA2 mutation are up to eight times more likely to develop breast cancer by the time they’re 80 years old than men who do not have this gene mutation. Men with a BRCA2 mutation also have a much higher risk of aggressive prostate cancer, while men with a BRCA1 mutation have a slightly higher-than-average risk of prostate cancer.
Like women, men with either BRCA mutation have a slightly higher risk of pancreatic cancer and melanoma.
Women with CDH1 mutation can have up to a 55% lifetime risk of invasive lobular breast cancer. People with CDH1 mutations also have a higher risk of developing diffuse gastric cancer, a rare type of stomach cancer.
Women with a PALB2 mutation and a family history of breast cancer have up to a 60% risk of developing breast cancer over their lifetimes. Women without family history have a 30-40% lifetime risk of breast cancer.
A PALB2 mutation is also associated with a higher risk of ovarian and pancreatic cancers, as well as breast cancer in men.
An STK11 mutation causes Peutz-Jeghers syndrome — a rare disorder in which people tend to develop a type of polyp in the small intestine, stomach, and colon. In addition to being at high risk gastrointestinal cancers, people with Peutz-Jeghers syndrome are also at higher risk of breast, lung, and ovarian cancers.
Inheriting a TP53 mutation is linked to Li-Fraumeni syndrome— a rare disorder in which people may develop soft tissue, adrenal, and brain cancers, as well as leukemia at a young age. The risk for some of these cancers last into adulthood. People with Li-Fraumeni syndrome may develop common cancers, such as breast, prostate, and colon, at much earlier-than-average ages.
The above list isn’t exhaustive. Researchers continue to look for genetic mutations linked to a higher risk of breast cancer.
Anyone who tests positive for a gene mutation linked to breast cancer may pass that mutation to any children they might have. Each child has a 50% risk of inheriting the cancer-related mutation.
If you test positive for a breast cancer-related mutation, all your blood relatives are at some increased risk of having the same gene mutation. For example, if you test positive for a BRCA1 or BRCA2 mutation your full siblings have a 50% risk of also having the same BRCA mutation.
Steps you can take if your results are positive
If you test positive for a mutation linked to breast cancer, you may be able to:
have more frequent cancer screenings that start at a younger age
have surgery to reduce your risk of breast cancer or ovarian cancer
take medicines to reduce your risk
use this information to help make treatment decisions if you’re ever diagnosed with breast cancer
If you test positive for a mutation that increases your risk, you can ask your doctor whether it makes sense to:
start breast cancer screening at a younger age (as young as 25)
have a clinical breast exam every six months in addition to monthly breast self-exams
have screening with MRI in addition to mammography
have screening more often than is recommended for people with an average risk of breast cancer, say alternating between a mammogram and a breast MRI every six months
According to the Basser Center at Penn Medicine, men who test positive for a BRCA mutation should receive yearly clinical breast exams and start doing breast self-exams at age 35.
If you have ovaries and a BRCA mutation, the American College of Obstetricians and Gynecologists recommends you begin annual pelvic exams at age 25. Some doctors also recommend that between the ages of 30 and 35, you consider annual ovarian cancer screening that includes pelvic ultrasound with an intravaginal probe and blood tests for a special protein called CA-125. The CA-125 protein can be higher than normal in people diagnosed with ovarian cancer. Still, CA-125 can be high in people without cancer, so a CA-125 test alone isn’t definitive.
Overall, it’s important to review the risks, benefits, limitations of ovarian cancer testing with your doctor, or, preferably, a gynecologic oncologist, or gynecologist with expertise in inherited cancer risk.
People who test positive for a mutation linked to breast cancer may choose to have a double mastectomy (called bilateral prophylactic mastectomy by doctors) to remove both breasts before cancer has a chance to develop. This is an extremely personal decision.
If you have a BRCA1 or BRCA2 mutation, the National Comprehensive Cancer Network recommends surgery to remove the healthy ovaries and fallopian tubes (called bilateral prophylactic salpingo-oophorectomy by doctors) between certain ages to reduce ovarian cancer risk (35-40 years for BRCA1 and 40-45 years for BRCA2).
While prophylactic mastectomy is an option, prophylactic salingo-oophorectomy is recommended. This is because ovarian cancer is hard to detect in its early stages. Researchers are working to develop non-surgical ways to reduce risk.
It’s important to have regular follow-up visits and monitoring as recommended by your doctor.
Some people who don’t want or can’t have risk-reducing surgery may be able to take medicines to lower their risk of breast cancer. Medicines used to lower breast cancer risk include tamoxifen, Evista (chemical name: raloxifene), Arimidex (chemical name: anastrozole), and Aromasin (chemical name: exemestane).
These medicines aren’t for everyone, as they can cause side effects that can affect your quality of life, including menopausal symptoms such as hot flashes. So it’s important to talk to your doctor about whether these medicines make sense for you.
Some doctors recommend women with a BRCA mutation take birth control pills to reduce ovarian cancer risk. Since birth control pills can increase breast cancer risk, it’s important to ask your doctor about the risks and benefits and if this option is right for you.
Knowing you have a BRCA mutation result can affect your treatment decisions if you’ve been diagnosed with HER2-negative breast cancer that is stage I through stage IV.
Medicines called PARP inhibitors, including Talzenna (chemical name: talazoparib) and Lynparza (chemical name: olaparib) are used to treat HER2-negative breast cancer that has a BRCA1 or BRCA2 mutation.
Testing negative for a mutation linked to breast cancer
There are two ways to interpret a report that says you are negative for a gene mutation linked to breast cancer:
A true negative is when you don’t have a gene mutation that another family member does have. For example, if you know that your mother has a BRCA1 mutation and you test negative for a BRCA1 mutation, it’s considered a true negative result.
A true negative result means that you have the same risk of developing breast cancer or ovarian cancer as anyone in the general population.
This happens if you test negative for a mutation that no other blood relatives have been tested or have tested negative as well. For example, if you have a strong family history of breast or ovarian cancer, but all of your family members have tested negative for a cancer-related gene mutation, it’s still possible that:
there’s a mutation in another gene that was not tested
there’s a mutation in a gene that researchers haven’t yet linked to cancer
Steps you can take if your results are negative
If you have a true negative result for a mutation linked to breast cancer then your breast cancer risk is the same as people in the general population and you should follow the screening guidelines recommended for them:
having annual or semiannual clinical breast exams, depending on your doctor’s recommendations
doing regular breast self-exams
having annual mammograms starting at age 40
What does it mean if I have a variant of unknown significance?
Your genetic test results may show that you have a variant of uncertain or unknown significance (VUS). This means that you have a mutation, but researchers aren’t sure if there’s a link to breast or other cancers.
If research later finds a variant of unknown significance that you have is linked to increased cancer risk, the lab that performed your genetic testing usually sends an updated report to your doctor or genetic counselor.
— Last updated on August 7, 2025 at 2:55 PM
