What is the CHEK2 Gene Mutation?

What is the CHEK2 Gene Mutation?

Medically reviewed by Dr. Doug Blayney on June 19, 2024.


Having a genetic mutation can sound really scary at first. A fellow cancer survivor once commented that when she heard she had a mutation, she immediately thought of the Teenage Mutant Ninja Turtles and the Hulk. But learning about what “mutation” means and how to manage it can help a lot. After I was diagnosed with breast cancer at 32 years old, I found out that I have a CHEK2 mutation, which increases my risk for certain cancers (in addition to the breast cancer I was already facing). Here's what I've learned about this mutation and how I'm managing my own experience. I’ve called in our go-to oncologist, Dr. Doug Blayney, to add to the science behind my experience. And if you have a CHEK2 mutation in your own family, please let us know in the comments of any details you feel are important.

Understanding the CHEK2 Gene Mutation

Understanding more about genetic mutations is really important because you can make better decisions about your care with your care team when you know what you’re dealing with. CHEK2 is one of several gene mutations known to participate in hereditary or inherited development of breast cancer and some other cancers.  

The Role of CHEK2 in Cancer Development

The CHEK2 gene is important because it makes a protein that stops cells from growing out of control. When cells are getting ready to divide, the CHEK2 protein checks to make sure their DNA isn't damaged. If something is wrong, it tells the cells to stop dividing until the problem is fixed. This helps prevent cancer from starting.

Why This Mutation Matters to You

When the CHEK2 gene is mutated or changed, the protein doesn't work properly. It can't do its job of checking cells before they divide. This means damaged cells might keep growing and dividing, which can potentially lead to cancer over time (that’s what happened to me!).

The Science Behind the CHEK2 Gene Mutation

We recently had a podcast that talked about genetic mutations. You can listen to the full podcast here, but here’s a quick definition: 

Germline mutation (often called a genetic mutation or genetic change): Changes in the genes passed from parents to children, affecting how the body develops and works. In one person, the germline mutations do not generally change over time. Many people are familiar with the breast cancer gene mutations, BRCA1 and BRCA2.

From Gene to Disease: The Pathway

Genes provide the instructions for making proteins in our bodies. The CHEK2 gene tells cells how to make the CHEK2 protein. But if the gene has a mutation or error, the instructions get messed up. The protein ends up misshapen and unable to function correctly.

How CHEK2 Mutation Increases Cancer Risk

Normally, the CHEK2 protein acts like a brake pedal to stop cell growth when it detects DNA damage. But with a mutation, it's like the brake doesn't work well anymore. So cells keep dividing even when their DNA is messed up. Over many years and cell divisions, those damaged cells can potentially turn into cancer.

The Impact of CHEK2 Gene Mutation on Cancer Treatment

When I learned that I had a CHEK2 mutation, there was a part of me that was glad to have a “reason” for my breast cancer. Or at least a partial reason, as who knows how many other layers of risk impacted my own experience. 

Treatment Options and Considerations

Having the CHEK2 mutation means you're at higher risk for some cancers, especially breast, colon, and prostate cancers. Your doctor may suggest getting cancer screenings like mammograms or colonoscopies more frequently to catch any cancer as early as possible. An important thing to keep in mind is that within the CHEK2 mutation, there are lots of different variants, which can indicate different levels of risk. This recent study talked about how “unknown variants” often make it tricky to accurately assess increased risk of cancer from a CHEK2 mutation.  Unknown variants (also called “variants of unknown significance” or “VUS”) usually are determined to be not pathogenic or disease causing variants as more experience is accumulated, you should remain in contact with your genetic counselor or genetic testing company as time goes by.  

Recent Advances in Addressing CHEK2-Related Cancers

Scientists are working on developing new treatments that target cancers caused by CHEK2 and similar genetic mutations. Medicines and therapies that help fix that "brake pedal" or bypass it in other ways could be very helpful for people with these mutations.

Living with a CHEK2 Gene Mutation

If, like me, you discover you carry this gene mutation, it can be scary at first. What does this mean for me? What does this mean for my family? After sitting with my news for a while, I came to believe that “information is power” really applies. Now that I know about my risk, I can start to manage that for me and for my family.

Navigating Cancer Risk Management

Finding out you have the CHEK2 mutation can be nerve-wracking at first. But try not to worry too much! There are lots of things you can do to manage your cancer risk, like getting recommended screenings, making healthy lifestyle choices, and considering medicines that can lower your risk.

Support and Resources for Patients and Caregivers

It's also really important to build a support network of family, friends, doctors, and counselors who understand what you're going through. They can help you get the care and emotional support you need on this journey.

Testing and Diagnosis for CHEK2 Gene Mutation

Understanding Your Testing Options

If you have a family history of cancer  particularly in first degree relatives (sisters, brothers, parents), your doctor may suggest genetic testing to check for mutations like CHEK2. This just involves giving a blood or saliva sample that gets analyzed in a lab. Also, if you had a cancer at a young age, as I did, this may also be a sign of a germline genetic mutation, and is a reason for germline genetic testing. Finally, if a relative has a germline genetic mutation which predisposes to cancer, you may want to obtain genetic testing for yourself (this is called “cascade testing).”  

What to Do If You Test Positive for CHEK2

Getting a positive CHEK2 test result means your cancer risk is higher, but it doesn't mean you'll definitely get cancer. Discuss the results with your doctor and genetic counselor, and make a plan for managing your risk through screening, prevention strategies (which may include mastectomy or other surgery), and a healthy lifestyle.

CHEK2 Gene Mutation and Family Health

As we talked about above, gene mutations can run in a family, which means your news may have an impact on your family, too.  This can be a difficult discussion to have with family members, so it’s often best to discuss these measures with a genetic counselor. 

Implications for Blood Relatives

The CHEK2 mutation can run in families. If you have it, your close blood relatives like siblings or children may also have an increased risk of carrying the mutation. It's a good idea to share your test results so they can get tested too if needed.

Discussing Genetic Risks with Your Family

Talking about genetic health can be difficult, but it's really important. Open and honest conversations with your relatives can help everyone understand their risks and make informed decisions about getting tested or taking preventive measures.

Our team “gets it”

The Manta Cares team is composed of cancer survivors, caregivers and oncologists - so we truly understand the challenges that come with a cancer diagnosis because we’ve been there. We are here to walk with you as you go through your own cancer experience. Please don’t hesitate to reach out with any questions. Be sure to subscribe to our newsletter and check out our free resources like our Chemotherapy Checklist for Caregivers, Financial Checklist for Cancer Treatment and more. We also put out a bi-weekly podcast called the Patient from Hell to educate, empower and hopefully inspire you as you go through this crappy experience. You can listen on Spotify, Apple Podcasts, YouTube or anywhere you listen to podcasts. Dealing with cancer as a patient or caregiver can feel really lonely. Just know that you are not alone in this experience.


Learning you have a CHEK2 or other genetic mutation that raises your cancer risk is never easy news. But understanding what it means and knowing the facts can go a long way towards easing your mind. With proper screening, prevention, and open communication, it's absolutely possible to take control of your health and manage the impacts of the CHEK2 mutation. Knowledge is power! And as a fellow CHEK-2’er (I think I’m going to make that “a thing!”), know that you are not alone in your experience!

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