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Some people inherit changes (mutations) in certain genes that increase their risk of breast cancer (and possibly other cancers). Genetic testing can look for mutations in some of these genes.

While it can be helpful in some cases, not everyone needs to be tested, and each person should carefully consider the pros and cons of testing. It’s very important to understand what genetic testing can and can’t tell you before these tests are done.

Inherited gene changes that can increase breast cancer risk 

BRCA1 and BRCA2 gene mutations

When it comes to breast cancer risk, the most important inherited gene changes are in the BRCA1 and BRCA2 genes. Women (and men) with one of these gene changes are said to have Hereditary Breast and Ovarian Cancer (HBOC) syndrome. 

• Women with a BRCA gene change have a greatly increased risk of breast cancer, as well as an increased risk of ovarian cancer, pancreatic cancer, and possibly some other cancers. 
• Men with a BRCA gene change are at increased risk of breast cancer (although this risk is lower than in women to begin with), prostate cancer, pancreatic cancer, and possibly some other cancers. 

If you have a family history of breast cancer, you have a higher risk of getting breast cancer yourself. Most women with a family history of breast cancer do not have an inherited gene change that greatly affects their risk. Still, an inherited gene change is more likely in women with a strong family history of breast cancer, especially if the family history also includes certain other cancers, such as ovarian, pancreatic, or prostate cancer. The risk of having an inherited syndrome is also affected by:

• Which family members are affected (Cancer in close relatives such as a mother or sister is more concerning than cancer in more distant relatives.) 
• The number of family members affected
• The age when your relatives were diagnosed (Cancer occurring at a younger age is more of a concern.)

Other inherited gene mutations

Inherited changes in some other genes can also increase breast cancer risk, including these genes:

• PALB2
• CHEK2
• ATM
• CDH1 (linked with hereditary diffuse gastric cancer)
• PTEN (linked with Cowden syndrome)
• TP53 (linked with Li-Fraumeni syndrome)

Considering genetic counseling and testing for breast cancer risk 

If you're concerned about your risk because of a personal or family history of breast cancer, talk with your doctor. As a first step, your doctor might use one of several risk assessment tools that are now available. These mathematical models use your family history and other factors to help give you and your doctor a better idea about your risk of having an inherited BRCA gene mutation. But these assessment tools aren't perfect, and each one might give different results, so doctors are still trying to figure out how best to use them.

Regardless of whether one of these tools is used, your doctor might suggest you could benefit from speaking with a genetic counselor or other health professional who is trained in genetic counseling. They can review your family history in detail to see how likely it is that you have a family cancer syndrome such as HBOC. The counselor can also describe genetic testing to you and explain what the tests might be able to tell you, which can help you decide if genetic testing is right for you. 

Genetic testing is covered by many health insurance plans, but it might not be covered (or might be covered only partially) by some of them.

If you do decide to get tested, the genetic counselor (or other health professional) can also help explain what the results mean, both for you and possibly other family members. To learn more about genetic testing in general, see Genetics and Cancer.

Testing for BRCA and other gene mutations

Some expert groups have developed guidelines for which women (and men) should consider genetic counseling and possibly testing for BRCA and other gene mutations. These guidelines can be complex, and not all doctors agree with them, but in general they include two main groups of people:

Women who have already been diagnosed with breast cancer: Most doctors agree that not all women with breast cancer need genetic counseling and testing. But counseling and testing is more likely to be helpful if: 

• You were diagnosed with breast cancer at a younger age
• You have triple-negative breast cancer
• You have been diagnosed with a second breast cancer (not a recurrence of the first cancer)
• You are of Ashkenazi Jewish descent
• You have a family history of breast cancer (especially at a younger age or in men), ovarian cancer, pancreatic cancer, or prostate cancer

Other groups of people: Genetic counseling and testing might also be recommended for other people who are at higher risk for inherited gene mutations, including:

• People with a known family history of a BRCA (or other) gene mutation
• Women diagnosed with ovarian cancer or pancreatic cancer, or men diagnosed with breast cancer, pancreatic cancer, or high-grade or metastatic prostate cancer
• People with a family history of breast cancer at a younger age, more than one family member with breast cancer, or breast cancer in a male family member
• People with a close family member with a history of ovarian cancer, pancreatic cancer, or metastatic prostate cancer

How genetic testing is done

Genetic testing can be done on samples of blood or saliva, or from a swab of the inside of a cheek. The samples are sent to a lab for testing.

There are many different possible mutations in the BRCA genes. Testing can look for one (or a few) specific mutation(s), or more extensive testing can be done to look for many different BRCA mutations. For example, if someone is being tested because they have a family member with a known BRCA mutation, testing might focus only on that specific mutation. In people of Ashkenazi Jewish descent, testing might focus on the specific BRCA mutations that are most common in this group of people. But if there’s no reason to suspect a specific gene change, testing will likely look for many different BRCA mutations. Depending on the situation, testing might be done to look for changes in other genes as well.

Getting the results of genetic testing

Before getting genetic testing, it’s important to know ahead of time what the results might or might not tell you about your risk. Genetic testing is not perfect. The tests might not provide clear answers for some people. This is why meeting with a genetic counselor or cancer genetics professional is important, even before being tested.

The results of genetic testing might come back as:

• Positive for a mutation that was tested for. If the test does find an important mutation, there might be steps you can take to help lower your risk of breast cancer (or other cancers). If you’ve already been diagnosed with breast cancer, a positive result might affect your breast cancer treatment options.
• Negative for the mutation(s) tested for. It can be reassuring to find out that the test didn’t find a mutation that increases your risk. But it’s important to know that genetic test results can’t always guarantee that you’re not at increased risk. For instance, there might be a chance that you have a gene change that is not currently being tested for.
• Inconclusive. In some cases, the test might not be able to tell for sure if you have a gene mutation.
• Positive for a variant of unknown significance (VUS). This means that the test found a gene change (variant), but it’s not known if this particular change affects your risk.

To learn more about these different types of test results, see What Happens During Genetic Testing for Cancer Risk?

The results of genetic testing can sometimes be complex or confusing, which is why it’s important to go over them with a genetic counselor or cancer genetics professional. They can explain what they might mean for you (and possibly other family members).

Direct-to-consumer genetic tests

Some genetic tests are now available directly to the public, but there are some concerns with these types of tests. For example, a test that looks for a small number of BRCA1 and BRCA2 gene mutations has been approved by the FDA. However, there are more than 1,000 known BRCA mutations. This means there are many BRCA mutations that would not be detected by this test. People with a negative test result might assume they don’t have to be concerned about their risk, when in fact they might still have a different BRCA mutation.

Our section on genetics and cancer has more information about genetic mutations and testing for them.