BRCA1 and BRCA2 gene testing


Description

The BRCA1 and BRCA2 gene test is a blood test that can tell you if you have a higher risk of getting cancer. The name BRCA comes from the first two letters of breast cancer.

What is the BRCA Gene Mutation?

BRCA1 and BRCA2 are genes that suppress malignant tumors (cancer) in humans. When these genes change (become mutated) they do not suppress tumors like they should. So people with BRCA1 and BRCA2 gene mutations are at a higher risk of getting cancer.

Women with this mutation are at higher risk of getting breast cancer or ovarian cancer. Mutations may also increase a woman's risk of developing:

Men with this mutation are also more likely to get cancer. Mutations may increase a man's risk of eveloping:

Only about 5% of breast cancers and 10 to 15% of ovarian cancers are associated with BRCA1 and BRCA2 mutations.

Who Should Think About Being Tested?

Before being tested, you should speak with a genetic counselor to learn more about the tests, and the risks and benefits of testing.

If you have a family member with breast cancer or ovarian cancer, find out if that person has been tested for the BRCA1 and BRCA2 mutation. If that person does have the mutation, you might consider getting tested, too.

Someone in your family may have the BRCA1 or BRCA2 mutation if:

You have a very low chance of having the BRCA1 or BRCA2 mutation if:

How is the Test Done?

Before the test is done, speak to a genetic counselor to decide whether to have the test.

If you decide to be tested, your blood sample is sent to a lab that specializes in genetic testing. That lab will test your blood for the BRCA1 and BRCA2 mutations. It can take weeks or months to get the test results.

When the test results are back, the genetic counselor will explain the results and what they mean for you.

What Does a Positive Test Result Mean?

A positive test result means you have inherited the BRCA1 or BRCA2 mutation.

When you know you are at higher risk of developing cancer, you can decide if you will do anything differently.

None of these precautions will guarantee you will not get cancer.

What Does a Negative Test Result Mean?

If your test result for the BRCA1 and BRCA2 mutations is negative, the genetic counselor will tell you what this means. Your family history will help the genetic counselor understand a negative test result.

A negative test result does not mean you will not get cancer. It may mean you have the BRCA1 or BRCA2 mutation, but the test results were not clear. It may mean you have the same risk of getting cancer as people who do not have this mutation.

Be sure to discuss all results of your tests, even negative results, with your genetic counselor.

References

BRCA and BRCA2: Cancer Risk and Genetic Testing. National Cancer Institute Web site. Last reviewed April 15, 2015. www.cancer.gov/cancertopics/factsheet/Risk/BRCA. Accessed October 7, 2015.

BRCA-Related Cancer: Risk Assessment, Genetic Counseling, and Genetic Testing. U.S. Preventive Services Task Force Web site. Current as of July 2015. www.uspreventiveservicestaskforce.org/uspstf/uspsbrgen.htm. Accessed October 7, 2015.

Gordon OK. Cancer of the breast and female reproductive tract. In: Rimoin D, Korf B, eds. Emery and Rimoin's Principles and Practice of Medical Genetics. 6th ed. Philadelphia, PA: Elsevier; 2013:chap 89.


Review Date: 8/1/2015
Reviewed By: Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
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