Genetic Testing for Hereditary Breast and Ovarian Cancer

How genetic testing can help you

Genetic testing can help you understand and manage your risk for breast, ovarian, and other cancers. Knowing whether or not you have a genetic mutation that makes you more likely to get cancer can help you decide what steps to take to prevent cancer or find it early.

Genetic counseling before genetic testing is important to find out if you and your family are likely to benefit from genetic testing.

Who should be tested

Usually, genetic testing is recommended if you have:

• A strong family health history of breast and ovarian cancers.
• A moderate family health history of breast and ovarian cancers and are of Ashkenazi or Eastern European Jewish ancestry.
• A personal history of breast cancer and meet certain criteria related to age of diagnosis, type of cancer, presence of certain other cancers or cancer in both breasts, ancestry, and family health history.
• A personal history of ovarian, fallopian tube, or primary peritoneal cancer.
• A known mutation in the breast cancer (BRCA) genes in someone in your family.

A genetic counselor can recommend the best tests for you and your family. When possible, testing should start with someone in the family should be someone who has had breast, ovarian, or another BRCA-related cancer.

How testing works

Genetic testing looks for inherited genetic mutations that can cause hereditary breast and ovarian cancers, such as mutations in the BRCA1 and BRCA2 genes. Your genetic counselor may suggest a test that looks for mutations in several genes, including BRCA1 and BRCA2, at the same time.

If you are of Ashkenazi or Eastern European Jewish ancestry, your genetic counselor may suggest testing for three specific BRCA gene mutations, called founder mutations. These are the most common mutations in people of Ashkenazi or Eastern European Jewish ancestry.

Genetic testing is done with a blood or saliva sample. The sample may be taken in a laboratory, doctor's office, hospital, or clinic. Or a kit may be sent to your home, and you send the kit to a laboratory that does the tests. It may take several weeks or longer to get the test results.

Interpretation of genetic test results may vary depending on whether you have had breast or ovarian cancer.

If your test result is positive

The test showed that you have a mutation known to cause hereditary breast and ovarian cancers.

What it means for you

• You can take steps to make it less likely that you will get cancer or to find cancer early if you get it.
• If you have had breast or ovarian cancer, a positive test result can help guide your treatment decisions.

What it means for your family

• If other family members decide to get genetic testing, their test should check for the same mutation you have.
• Your parents, children, sisters, and brothers each have a 1 in 2 (50%) chance of having the same mutation.

If your test result is negative

The test didn't find that particular mutation. But what this means for you depends on your personal and family history of cancer and whether another relative is known to have a mutation.

• If you have a close relative with a BRCA gene mutation, your negative test result means you didn't inherit that mutation and can't pass it to your children. A negative test result doesn't mean you won't get cancer, and you may still be at higher risk for cancer depending on your family history.
• If you don't have a close relative with a BRCA gene mutation and you've never had cancer, your negative test result means you don't have a known BRCA gene mutation. You have the same risk of cancer as the general population. Depending on your family history and other risk factors, you may be at higher risk.

You may still get cancer, even if you test negative for a BRCA gene mutation. You will have the same risk of getting cancer as the average person. If you have a family history of cancer or other risk factors, you may still have a higher risk of getting cancer.

If your test result is variant of uncertain significance (VUS)

The test found a mutation in one of the genes associated with hereditary breast and ovarian cancers, but doctors don't know if that mutation causes cancer. Some mutations prevent genes from working properly, while others have no effect. It is not always easy to tell whether or not a mutation in a gene has a harmful effect.

• If you have had breast or ovarian cancer, it is unclear whether the mutation found in the test caused your cancer. Further testing may be available.
• Whether or not you have had breast or ovarian cancer, you are at higher risk for the cancers that run in your family.

Lisa: My Experience with BRCA Counseling and Testing

Lisa talks about how her family history led her to get genetic counseling and testing for BRCA gene mutations. In this video, she describes the genetic testing experience and explains how it helped her understand her family history and manage her risk for breast cancer.

More information

• BRCA Gene Changes: Cancer Risk and Genetic Testing (National Cancer Institute)
• Genetic Testing for Inherited Cancer Risk (National Cancer Institute)
• Genetic Testing and Your Cancer Risk (MedlinePlus)
• BRCA1 and BRCA2 Gene Testing (MedlinePlus)