November 16, 2021

Breast Cancer Genes Explained: How & When To Get Tested

Learn about BRCA and other genes that raise the risk of breast cancer

An illustration of computer screen with a doctor wearing a breast cancer ribbon

Breast cancer is the most common cancer in women after skin cancer — and up to 15% of people with breast cancer have a genetic or inherited cause for the disease.

Advertisement

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

Researcher Charis Eng, MD, PhD, explains what you need to know about breast cancer genes and genetic testing.

What genes are linked to breast cancer?

The term “breast cancer genes” means genes that, when altered (mutated), increase your risk of getting breast cancer. These gene mutations shut down some of your natural cancer-fighting genes. When you don’t have your full army of genes fending off cancer, your risk of certain cancers goes up.

“BRCA1 and BRCA2 are the most common breast cancer genes when mutated, followed closely by PTEN mutations,” says Dr. Eng. “But several other breast cancer gene mutations exist. We know of at least 14 different genes right now, and we are currently exploring several others, too.”

These gene mutations aren’t limited to breast cancer risk. Some of these gene mutations may also increase the risk of:

How common are breast cancer gene mutations?

“Breast cancer gene mutations aren’t common in the general population,” Dr. Eng says, “but they are common in people who have breast cancer. About 10% to 15% of people with breast cancer have one of the breast cancer gene mutations.”

You can inherit these gene mutations from either of your biological parents, and the cancers they’re linked to can affect both men and women — so consider all your relatives when thinking about your family history.

Who should get breast cancer genetic testing?

Genetic testing is the only way to know whether you have a breast cancer gene. These blood tests check for BRCA1 and BRCA2, as well as other known breast cancer genes.

Advertisement

If you have already been diagnosed with breast cancer, you may need genetic testing if you:

  • Are of Ashkenazi Jewish descent.
  • Were born biologically male.
  • Have a family history of breast cancer, especially if the relatives were male or under age 45 when they were diagnosed.
  • Have a family history of ovarian, pancreatic or prostate or other (e.g. thyroid) cancer.
  • Have a second breast cancer (not a recurrence of the first cancer).
  • Have triple-negative breast cancer that was diagnosed before you were 60.
  • Were diagnosed with breast cancer at age 45 or younger.

If you haven’t been diagnosed with breast cancer, consider genetic testing if you:

  • Were born biologically male and have been diagnosed with pancreatic cancer or high-grade metastatic prostate cancer.
  • Have a close family member with cancers, including ovarian cancer, pancreatic cancer or metastatic prostate cancer.
  • Have a known family history of the BRCA (or other) gene mutations.
  • Have a male relative with breast cancer or a female relative with cancer in both breasts.
  • Have been diagnosed with ovarian or pancreatic cancer.
  • Have family members who were diagnosed with breast cancer before age 45.
  • Have more than one family member with breast cancer.

Genetic tests are helpful for people with risk factors, but not everyone needs them.

“Testing everyone in the general population would be like trying to find a needle in a haystack,” Dr. Eng says. “Most people would get negative results. And right now, the world doesn’t have enough geneticists to see all those patients and do a follow-up. Knowing your family history is important because it tells us who needs to be tested or if you need to be tested.”

How do I get tested for BRCA and other genes?

If your doctor finds that you’re at risk for hereditary breast cancer, they will refer you to a genetics professional, such as a genetic counselor, for genetic evaluation and pre- and post-test genetic counseling. Then, your blood is drawn and sent to a clinical lab for genetic analysis.

A geneticist (genetics expert) reads your blood test results and follows up with your provider. If you have a positive result, you’ll meet with your genetic counselor to discuss next steps for your care.

What your breast cancer genetic tests results mean

Having a positive genetic test result doesn’t mean you’ll get cancer. It means you have a higher risk of getting breast cancer than people without the mutation.

Advertisement

Consider these statistics:

  • Women without breast cancer gene mutations have a 12% lifetime risk of breast cancer.
  • Women with a BRCA mutation have up to an 80% lifetime risk of breast cancer.
  • Women with the PTEN mutation have an 85% lifetime risk.
  • Men with the BRCA2 mutation have about an 8% lifetime risk, 80 times greater than males without the mutation.

Even if you get tested and get a negative result, don’t skip mammograms or other health screenings, and continue to follow the American Cancer Society’s guidelines.

“Most cases of breast cancer aren’t hereditary,” says Dr. Eng. “A negative result means you don’t have the known gene mutations for breast cancer. But you can still get breast cancer.”

How your test results can help you

A positive result for breast cancer genes can be difficult to deal with. But you can use this information to your advantage.

“If we know you have a breast cancer gene alteration, we can take extra steps to catch cancer early, when it’s most treatable,” Dr. Eng says. “Your providers can perform enhanced screenings starting at an early age, usually 25 or 30, depending on the gene. Knowledge is power.”

Related Articles

Scientist using microscope.
February 17, 2023
Why Genetic Testing for C3G May Be an Important Choice

It can help determine a best treatment path

Woman and physician discuss medical result in office setting.
October 14, 2022
The Importance of Palliative Care for Metastatic Breast Cancer

This support system is invaluable

Breast cancer cell spreading
October 10, 2022
How Fast Does Breast Cancer Spread?

Rate of growth depends on cancer type, stage and grade, as well as individual factors

Nurse drawing blood from female patient.
September 12, 2022
Link Between Metastatic Breast Cancer and Anemia

Treatments like chemotherapy and radiation can cause your red blood cell levels to decrease

preforming genetic testing in the lab
December 16, 2020
A Genetic Test You Don’t Need

Testing MTHFR is usually unnecessary

woman in genetic counseling
December 1, 2020
What Genetic Counselors Can Do for You

Learn how they can help your health

woman undergoing chemo treatment
October 13, 2020
Should You Have Chemotherapy Before Surgery for Breast Cancer?

A breast cancer specialist discusses if and when it's the right decision

Trending Topics

group of hands holding different beverages
November 14, 2023
10 Myths About Drinking Alcohol You Should Stop Repeating

Coffee won’t cure a hangover and you definitely shouldn’t mix your cocktail with an energy drink

Person applies moisturizer as part of their skin care routine after a shower.
November 10, 2023
Korean Skin Care Routines: What You Need To Know

Focus on the philosophy — replenishing and respecting your skin — not necessarily the steps

glass of cherry juice with cherries on table
November 8, 2023
Sleepy Girl Mocktail: What’s in It and Does It Really Make You Sleep Better?

This social media sleep hack with tart cherry juice and magnesium could be worth a try

Ad