What is a BRCA gene test?
A BRCA gene test uses a sample of your blood, saliva (spit), or cells from inside of your cheek to look for changes in your BRCA1 and BRCA2 genes that may increase your risk of cancer. Changes in your genes are called gene variants or mutations. Not all gene variants are harmful.
Genes are parts of DNA that you inherit from your parents. They carry information that controls what you look like and how your body works. BRCA genes repair damaged DNA in your cells and protect you from getting certain types of cancer. If you have a harmful variant in your BRCA genes, they may not work properly. This increases your risk of getting cancer.
The most common cancers linked to harmful BRCA variants are:
- Breast cancer. BRCA is short for breast cancer gene. The increased risk for breast cancer mostly affects females. But the breast cancer risk for males who have a harmful BRCA variant is higher than for other males.
- Ovarian cancer. This is cancer of the female reproductive glands where eggs form.
- Prostate cancer. This is cancer of the male reproductive gland that makes fluid for semen.
- Pancreatic cancer. This is cancer of the pancreas, an organ that helps you digest food and makes important hormones.
Not everyone who has a harmful variant in BRCA1 or BRCA2 will get cancer. And if you find out you have a harmful variant, you may be able to take steps to lower your risk and protect your health.
Other names: BRCA gene test, BRCA gene 1, BRCA gene 2, breast cancer susceptibility gene1, breast cancer susceptibility gene 2
What is it used for?
This test is used to find out if you have harmful changes in your BRCA1 or BRCA2 genes that increase your risk of getting certain cancers, especially breast, ovarian, prostate, and pancreatic cancer.
Why do I need a BRCA gene test?
Harmful BRCA gene variants are rare. They affect only about 0.2 percent of the U.S. population. So, BRCA testing is not recommended for most people.
You and your family members are more likely to have a BRCA1 or BRCA2 variant if either side of your family has a strong history of breast or ovarian cancer. If you're concerned that you may have a harmful variant in the BRCA1 or BRCA2 gene, your health care provider or a genetic counselor can review your personal and family health history to see if you need this test.
In general, it's important to talk with a provider about BRCA testing if your personal or family health history includes:
- Breast cancer, especially:
- Before age 50
- In both breasts
- In a male
- Triple negative breast cancer which has limited treatment options, including chemotherapy and/or surgery
- Cancer of the ovaries, fallopian tubes (tubes connecting the ovaries to the uterus), or peritoneum (tissue that covers your belly organs).
- Prostate cancer that spreads to other parts of the body (metastatic cancer).
- Pancreatic cancer.
- Ashkenazi (Eastern European) Jewish ancestry. BRCA variants are much more common in this group compared with the general population. They are also more common in people from other parts of Europe, including Iceland, Norway, and Denmark.
- A relative already diagnosed with a harmful gene variant in BRCA1 or BRCA2.
When you think about your family health history, consider all breast, ovarian, prostate, and pancreatic cancers on both sides of your family. And consider the health of your grandparents, parents, aunts and uncles, siblings, half-siblings, nieces and nephews, and grandchildren.
What happens during a BRCA gene test?
A BRCA test can use either a sample of your blood, saliva, or a cheek swab.
For a blood test: A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
For a saliva test: You'll spit into a container or use a cotton pad to soak up some saliva.
For a cheek swab: A health care professional will wipe the inside of your cheek with a small tool to remove some cells. You may have the option of doing it yourself.
An at-home test kit is available to buy without a prescription. It allows you to collect a saliva sample to send to a lab for testing. The test checks for the three most common harmful variants in BRCA genes. But there are more than 1000 known variants. So, a home test can't rule out the possibility that you have a variant. Ask your provider whether an at-home test is right for you.
Will I need to do anything to prepare for the test?
For a blood test: You don't need any special preparations.
For a saliva test: A half hour before the test, you may need to stop eating, drinking, or smoking. Follow all the instructions your provider gives you or the instructions in an at-home kit.
For a cheek swab: You may be asked to rinse your mouth before the test.
With any type of genetic test, you may want to meet with a genetic counselor first to see if testing is right for you. Your counselor can explain the pros and cons of learning more about your cancer risk. After your test, a counselor can help with the medical and emotional impact that your results may have on you and your family.
Are there any risks to the test?
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
There are no risks linked to providing a saliva sample or having a cheek swab.
What do the results mean?
Your provider or genetic counselor will need to explain how your results affect your risk for certain cancers. That's because the meaning of your test results depends on the exact type of variant you have and your personal and family health history.
In general, your results may be reported using these terms:
- A negative (normal) result means that the test didn't find any harmful changes in your BRCA genes. How this affects your cancer risk depends on whether you've already had cancer and whether a member of your family has a harmful BRCA variant.
- An uncertain result may also be called a "variant of uncertain significance (VUS)". It means that a variant in your BRCA genes was found, but researchers don't know whether that variant causes cancer.
- A positive result may also be called a "likely pathogenic variant." It means that you have a harmful gene variant that is known to increase the risk of certain cancers. But the test cannot tell whether you will develop cancer.
Learn more about laboratory tests, reference ranges, and understanding results.
Is there anything else I need to know about a BRCA gene test?
If your results show that you have a harmful variant in your BRCA genes, talk with your provider about ways to lower your cancer risk. You may discuss:
- Your schedule for cancer screening tests. Should you get tested for cancer sooner and more often than usual? These are important questions for all adults who have a harmful BRCA variant.
- Taking certain medicines and/or having surgery to reduce the risk of cancer. Surgery may include removing both breasts and/or the ovaries and fallopian tubes.
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- Centers for Disease Control and Prevention [Internet]. Atlanta: U.S. Department of Health and Human Services; Bring Your Brave Campaign: BRCA Gene Mutations; [reviewed 2021 Sep 27; cited 2022 Jun 6]; [about 12 screens]. Available from: https://www.cdc.gov/cancer/breast/young_women/bringyourbrave/hereditary_breast_cancer/brca_gene_mutations.htm
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