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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 changes in some of these genes.

While it can be helpful in some cases, not everyone needs to be tested. Each person should carefully consider the benefits and risks of genetic 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

Several gene changes can increase the risk of developing breast cancer. Some of these gene changes are considered “high penetrance.” That means people with the gene change have a much higher risk of breast cancer. These gene changes include:

• BRCA1 (linked with Hereditary breast and ovarian cancer syndrome)
• BRCA2 (linked with Hereditary breast and ovarian cancer syndrome)
• CDH1 (linked with Hereditary diffuse gastric cancer)
• PALB2
• PTEN (linked with Cowden syndrome)
• STK11 (linked with Peutz-Jeghers syndrome)
• TP53 (linked with Li Fraumeni syndrome)

Some gene changes have “moderate penetrance.” That means the risk of breast cancer with these changes is higher than that of someone without them. But the risk is not as high as the high penetrance gene changes. These gene changes include:

• NF1 (linked with Neurofibromatosis type 1)
• ATM (linked with Ataxia-Telangiectasia)
• CHEK2
• BARD1
• RAD51C
• RAD51D

Researchers are working to find out if other gene changes can help predict the risk of developing breast cancer. This is important so that those people at higher risk can be offered treatments to reduce their risk or find cancer earlier, when it may be more treatable.

See Breast Cancer Risk Factors You Cannot Change for more information on these gene changes.

How family history affects the risk of an inherited gene change

If you have a family history of breast cancer, you have a higher risk of getting breast cancer yourself. Most people with an inherited gene change have a family history of breast cancer. However, not everyone with a family history of breast cancer has an inherited gene change. A family history of other cancers, such as ovarian, pancreatic, or prostate cancer, may make an inherited gene change more likely.

The risk of having an inherited syndrome is also affected by:

• The number of family members affected
• 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 age when your relatives were diagnosed: Cancer diagnosed at a younger age is more of a concern

All of these factors should be considered when deciding whether to have genetic testing.

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 healthcare team.

Your doctor might suggest you could benefit from speaking with a genetic counselor. At this appointment, the counselor reviews your family history in detail. They 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 results would mean. This can help you decide if genetic testing is the right choice for you.

Genetic testing is covered by many health insurance plans. But it might only be partially covered or not covered by some plans.

To learn more about genetic testing in general, see Genetics and Cancer.

Who should consider genetic testing

Some expert groups have developed guidelines for who should consider genetic counseling and possibly testing for BRCA and other gene mutations.

These guidelines can be complex, and not all doctors agree, but in general they include two main groups of people:

People who have already been diagnosed with breast cancer

Most doctors agree that not everyone with breast cancer needs 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, especially younger than 50.
• You have triple-negative breast cancer.
• You were diagnosed with a second breast cancer that is not a recurrence of the first cancer.
• You were diagnosed with multiple breast cancers at the same time.
• You are of Ashkenazi Jewish descent.
• You have a family history of breast cancer, especially at a younger age or in men.
• You have a family history of ovarian cancer, pancreatic cancer, or prostate cancer.
• Tumor gene testing found a gene change. If this change is found in other cells in your body, it might affect your health.
• You have lobular breast cancer and a personal history of or a close family member with diffuse gastric 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 change
• Women diagnosed with ovarian cancer or pancreatic cancer.
• 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 it can be done from a swab of the inside of a cheek. A sample might be collected in a clinic or hospital, or your clinic may have an at-home test sent to you to mail in for testing. The samples are sent to a lab for results.

There are many different possible gene changes that could increase the risk of breast cancer. Testing can look for a specific one, especially if there is one that is known to run in the family. For example, if someone has a family member with a known BRCA mutation, testing might focus only on that specific gene.

Testing can also look for a set of genes that may increase the risk for breast cancer. This is called a gene panel.

Getting the results of genetic testing

Before having 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.

Types of genetic test results

The results of genetic testing might come back as:

Positive for a mutation: If the test finds 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. However, it’s not known if this change affects your risk.

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

How results affect your healthcare decisions

Genetic testing results can affect your healthcare choices. Depending on what they show, your healthcare team may recommend more frequent follow-up, screening tests, or other treatments like medicine or surgery to lower your risk of breast cancer.

Working with a genetic counselor

The results of genetic testing can sometimes be complex or confusing. A genetic counselor or other health professional can help explain what the results mean, both for you and possibly other family members. 

At-home genetic tests

Some genetic tests are now available to buy and do at home. But there are some concerns with these types of tests. For example, a test that looks at the BRCA1 and BRCA2 genes has been approved by the FDA. However, it only looks at a few of the more than 1,000 known BRCA mutations. This means there are many BRCA mutations that are not detected by this test. People with negative test results might assume they don’t have to be concerned about their risk, when in fact they might have a different BRCA mutation.

See Genetics and Cancer for more information about genetic mutations and testing for them.

More resources

Learn more about genetic testing to determine cancer risk.