Genetic Testing for Breast Cancer: What to Know
Writer: Amy Harris
Unfortunately, we all know someone who has had breast cancer. One in eight women will get breast cancer in their lifetime. This year, an estimated 43,000 women will lose their battle with breast cancer.[1] It makes sense that we all would like to be able to find cancer earlier. Fortunately, scientists and healthcare providers have begun identifying factors that put some people at greater risk than others.
While only a very small percentage of breast cancers are caused by changes in your genes, breast cancer genetic screening tests can help healthcare providers find cancer earlier and with more effective treatment. As part of your breast cancer awareness plan, learn more about breast cancer genetic screening tests and whether they make sense for you.
What Is Genetic Testing?
Genetic testing studies your DNA—the chemical code with the instructions your body needs to stay alive and healthy. Genetic testing can reveal changes, called mutations, in your genes that may cause breast cancer.[2]
Genetic Testing For Breast Cancer
Changes in DNA do not cause the majority of breast cancers. Only a very small amount of breast cancers (5%–10% in the U.S.) are caused by genetic mutations.[3]
Genetic testing does not tell you whether or not you have breast cancer. It can help people learn if their family history of breast cancer is due to an inherited gene mutation. For some people diagnosed with breast cancer, genetic testing can help guide treatment.
At this time, there are three different types of breast cancer genetic screening tests. They are done on a small sample of fluid or tissue from your body, most often your blood. A genetic testing laboratory then processes your sample. Test results are typically returned within two to three weeks.[4]
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BRCA-1 and BRCA-2 (BRCA1/2). The primary genetic test for breast cancer screens for mutations or changes in the BRCA-1 or BRCA-2 genes (pronounced brah-kuh). Having the BRCA1/2 mutations also increases your risk for ovarian cancer. It can run in families. Men can also be carriers of the BRCA1/2 genes.[5,6]
Family members share some, but not all, of their genes. Just because one person in your family has the BRCA1/2 gene doesn't mean everyone in the family has the gene. Only about four out of every 100 breast cancers are caused by a BRCA mutation, but if your biological parent has the BRCA mutation, then you have a 50% chance of also having the mutation.[3]
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Hereditary gene panel tests. Besides the BRCA genes, researchers have identified other genetic mutations that increase a person's risk for other cancers, including breast cancer.[3] These genetic tests can test for 40 to 75 different genes simultaneously—all from a sample of your blood or saliva.[3]
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Multigene early detection test. This newer type of genetic test also screens for more than one type of cancer with one blood test. However, instead of mutations in your DNA code, this test measures whether you have certain cancer signals, or pieces of DNA in your bloodstream.[7]
How Accurate Is Genetic Testing for Breast Cancer?
It is important to remember that the genetic tests we have so far for breast cancer are not perfect. There are several reasons why test results may not be correct or helpful.
- Results can be variable. Tests still have a margin of error. The quality of laboratory testing, the sample you provide, and differences in gene markers impact accuracy.[3,8]
- False negatives are possible. A false negative means that you didn't test positive for a gene linked with an increased risk of breast cancer. However, you could still be at higher risk—science just hasn't come up with a genetic test for your type of risk factor.[8]
- Variants of unknown significance (VUS) can be your result. The human genetic code is unbelievably complex. Your test result could indicate a genetic variation at the part of your DNA known to influence breast cancer risk, but scientists don't yet know whether that variant will impact your chances of getting cancer. This is called a variant of unknown significance and can be confusing.[4]
For all of the genetic tests for breast cancer, a positive test result does not mean that you have cancer. The result only indicates that the laboratory found a change associated with an increased cancer risk. For the BRCA1/2 test, a negative test result means that no changes in the BRCA1/2 genes were found.[6]
The multigene early detection tests can identify where in the body cancer DNA fragments may be originating, such as in breast tissue.[7,9] Multi-cancer early detection (MCED) tests like Galleri are investigational tools that may detect a cancer signal in the bloodstream, but are not currently approved as a breast cancer screening method. They cannot replace mammograms or genetic testing for BRCA mutations.
A negative test result on a multigene early detection test means that you most likely do not have a cancer shedding the DNA fragment at the time you took the test. It does not tell you anything about your risk of developing breast cancer (or other cancers) in the future.[9]
Genetic Testing for Breast Cancer: Pros and Cons
Deciding whether or not to have genetic testing for breast cancer is an important decision that is much more complicated than, say, testing for COVID.
Potential Benefits
- You may feel less uncertainty about your risk of breast cancer.
- You can get screened at a younger age or more often, leading to earlier detection and treatment if you test positive for a mutation.
- You may be able to take medications or have surgery to reduce your risk if you test positive.
- You may have more motivation to change personal behaviors (quitting smoking, exercising, healthy eating).
- You can get help to guide decisions about fertility and future pregnancies if you test positive.[4]
Potential Drawbacks
- Low probability of finding a causative mutation if you (or a single older relative) are the only person in the family with breast cancer.[3,10]
- Cost, if insurance does not cover testing.
- Increased worry, fear, stress, or depression because of uncertainty in results.
- Family tension if you test positive for an inherited gene (e.g., BRCA1/2).
- Privacy concerns—results may appear in the medical record; protections can vary.[3,10]
Since there are significant emotional, financial, and social risks of genetic testing for breast cancer, genetic testing isn't routinely advised for people with an average risk of breast cancer.[3,11]
The United States Preventive Services Task Force (USPSTF) recommended in 2019 against routine risk assessment, genetic counseling, or genetic testing for women whose personal/family history or ancestry is not associated with BRCA1/2 gene mutations, and is updating guidance now.[12] Instead, they recommend women get mammograms every other year, starting at age 40 and continuing until age 74.[13]
At-Home Breast Cancer Genetic Testing
Most people considering genetic testing have it done at a healthcare facility, overseen by a healthcare professional.[2] A specially trained health professional, called a genetic counselor, can help you:[3,6]
- Decide if and what type of genetic test for breast cancer is right for you, and explain what results could mean.
- Understand your risk and your family’s medical history.
- Determine the test cost and whether insurance will cover it.
Some people choose at-home testing options for privacy, convenience, or other personal reasons. Keep in mind that if you choose an at-home option and your test is positive, it’s recommended that you meet with a genetic counselor and repeat testing in a clinically approved laboratory.[3]
Should You Take a Breast Cancer Genetic Screening Test?
Nearly all healthcare decisions are complicated, but choosing to have genetic testing is a deeply personal and impactful decision. Deciding whether or not to have testing can depend on:[3,4]
- Cost and your insurance coverage
- Whether you have a family history of breast cancer
- Your age
- Your sex (men have lower risk than women, but ~1 in 20 men has a BRCA1/2 inherited mutation)
Talking with a healthcare provider can help you get a better sense of your actual risk and whether it makes sense for you to be tested. Given that the majority of breast cancers are not inherited, the mainstay of reducing risk remains:[13]
- Breast cancer awareness
- Breast cancer screening
- Prevention
Virtual care visits offered through Everlywell allow you to speak 1-on-1 with experts about the latest breast cancer screening guidelines. They can help you learn more about breast cancer so you can make informed decisions about how genetic testing may or may not fit into your personalized prevention plan.
References
- American Cancer Society. Key statistics in breast cancer. May 5, 2025. Accessed July 24, 2025.
- Genetic testing. Mayo Clinic. April 14, 2020. Accessed July 24, 2025.
- Susan G. Komen Foundation. Genetic testing to learn about breast cancer risk. March 24, 2025. Accessed July 24, 2025.
- National Cancer Institute. Genetic testing for inherited cancer risk. April 18, 2024. Accessed July 24, 2025.
- American Cancer Society. Breast cancer risk and prevention: Genetic testing. December 16, 2021. Accessed July 24, 2025.
- Mayo Clinic. BRCA gene testing for breast and ovarian cancer risk. October 21, 2023. Accessed July 25, 2025.
- Schrag D, Beer TM, McDonnell CH, et al. Blood-based tests for multi-cancer early detection (PATHFINDER). Lancet. 2023;402:1251-1260.
- Eccles DM, Mitchell G, Monteiro AN, et al. BRCA1/2 testing—managing variants of uncertain significance. Ann Oncol. 2015;26(10):2057-2065.
- Cleveland Clinic. The Galleri Test: A new blood test for cancer screening. April 5, 2022. Accessed July 25, 2025.
- McCormick CZ, Yu KD, Johns A, et al. Psychological impact after receiving genetic risk results. J Pers Med. 2022;12(12):1943.
- American Society of Breast Surgeons. Genetic testing for hereditary breast cancer. Clinical Consensus Statement. Feb 10, 2019.
- USPSTF. BRCA-Related Cancer: Risk Assessment, Genetic Counseling, and Genetic Testing. Aug 20, 2019.
- USPSTF. Breast cancer screening. Apr 30, 2024.