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STK11 and Lung Cancer

Testing for errors in the STK11 gene helps your doctor understand your lung cancer and recommend treatments that may work better for you.

STK11 at a Glance:

  • Errors in the STK11 gene are one type of lung cancer biomarker.  
  • Biomarker testing can help match you to targeted treatments.
  • You can ask for testing at diagnosis or if treatment stops working.

Frequently Asked Questions about Biomarker Testing

What Is the STK11 Mutation?

Errors in the STK11 gene are one type of lung cancer biomarker that doctors look for when diagnosing and treating lung cancer. Where there is a mutation in the STK11 gene (also called LKB1), the STK11 protein inactivates and stops working properly. This leads to uncontrolled cell growth, which can cause cancer. 

Several STK11 gene mutations have been found that can inactivate the STK11 protein. Researchers are still trying to understand if the different types of STK11 mutations impact treatment options.

Who is more likely to have a STK11 mutations?

In general, the STK11 mutation is more common in patients with adenocarcinoma non-small cell lung cancer (NSCLC) who have a smoking history.  However, they can exist in any patient, regardless of smoking status.  

It is often, but not always, found alongside another mutation called KRAS. STK11 is the third most frequently mutated gene in NSCLC (10% overall; 20% in lung adenocarcinoma). 

Dr. Erin Schenk explains what a STK11 mutation is in lung cancer. This video was produced in 2020. For the latest treatment options, speak with your doctor.

Video transcript

Why STK11 Biomarker Testing Matters

Biomarker testing matters for STK11 because STK11 mutations can influence how lung cancer grows and how well certain treatments, especially immunotherapy, may work, making it an important marker for understanding the disease and planning care. 

Biomarker testing looks for specific genetic changes in the tumor to help guide treatment. Testing includes DNA-based tests to identify changes in the genes themselves, and RNA-based tests to measure how those genes behave, giving your care team a fuller picture of your tumor makeup and available treatment options.

How Is STK11 Testing Done?

Testing is usually done at diagnosis or when treatment changes. Your doctor will need to test your tumor through a tissue or blood (liquid) biopsy. There are several different types of tests that doctors use to look for changes, or biomarkers in your cells:

  • Fluorescence in Situ Hybridization, or FISH, analysis is a common genetic test. FISH analysis looks at changes in the chromosomes through tissue under a microscope.
  • Immunohistochemistry (IHC) looks for proteins in the cell under a microscope.
  • Next-generation sequencing (NGS), also called comprehensive biomarker testing, is when tissue from a patient's tumor (gathered from a biopsy) is placed in a machine that looks for many possible biomarkers at one time.
  • Reverse transcription polymerase chain reaction (RT-PCR) is a laboratory method used to make many copies of a specific genetic sequence for analysis.

Your doctor may perform several of these tests at the same time to help confirm results. Different biomarkers rely more heavily on certain tests.

Testing for STK11 looks for mutations in the STK11 gene that may help doctors understand how the cancer behaves and how it might respond to treatment. STK11 mutations are usually identified using NGS. Because STK11 is a DNA‑based mutation, other tests like IHC, FISH, or PCR are not typically used. Liquid biopsy may detect STK11 mutations when tissue is limited. 

Learn more about the different types of biomarker tests. 

Understanding Your STK11 Test Results

An STK11‑positive result means your cancer has a mutation in the STK11 gene. This mutation can influence how the cancer behaves and how well certain treatments, especially immunotherapy, may work. 

An STK11‑negative result means no mutation was found in this gene, so STK11 is unlikely to affect your treatment plan.

An unclear result means the test couldn’t confirm whether an STK11 mutation is present. Your care team may recommend repeating the test or using a different sample to get a clearer answer. 

How STK11 Results Influence Treatment

Having STK11 mutation does not impact first-line treatment, which is often chemotherapy and/or immunotherapy. However, researchers are looking closely at the role of dual immunotherapy in patients with an STK11 mutation.

Questions to Ask Your Doctor

Work with your doctor to discuss your goals and options each time you have to review and interpret test results to make a treatment decision. The three big questions to ask are:

  • What is the goal of this treatment?
  • What are the potential side effects?
  • What other options do I have?

Research is happening at a rapid pace, and your doctor should be up to date on the recommendations for your specific type of lung cancer. If you don’t feel comfortable with the answers you are receiving, do not hesitate to seek out a second opinion.

What to Do After STK11 Diagnosis

Someone with a STK11 mutation can take several empowering steps to stay ahead of their care. These are general medical information steps, not personal medical directives, and it’s important to work closely with a qualified healthcare professional for decisions about diagnosis or treatment. 

STK11 often appears alongside other mutations like KRAS or KEAP1, which can influence how the cancer behaves and which treatments may be most effective. 

STK11 mutations can be linked to lower response rates to certain immunotherapies, so your care team may discuss combination treatments or alternative approaches. 

Keeping notes on symptoms, side effects, or changes in your daily health helps your care team support you and adjust treatment if needed. 

Patient Support & Resources

Lung cancer research can move at a rapid pace. Always speak with your doctor about the most up-to-date treatment guidelines.

Medically reviewed by: Jorge Gomez, MD
Last reviewed: June 2026 

Page last updated: August 13, 2026

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