When tumor tissue is looked at under a microscope, physicians can see what type of cancer it is. But physicians can also look for changes in the DNA of the tumor that might be causing the tumor to grow. Sometimes these changes are called biomarkers or molecular markers.

One way to think about it is that our DNA is like an instruction manual. If there is a typo in the instruction manual, the cell receives wrong instructions and can grow into cancer. Biomarker testing looks for those typos, so physicians know if you are a candidate to receive a targeted therapy that directly addresses those typos. 

A mutation in the STK11 protein is one biomarker that physicians look for in non-small cell lung cancer. If you have non-small cell lung cancer, it is important to talk to your doctor about comprehensive biomarker testing to see if you have an STK11 mutation or another biomarker. The results of this testing influence your treatment options. To learn more about biomarker testing, visit Lung.org/biomarker-testing

What is the STK11 mutation?

STK11 mutations inactivate the STK11 protein. This leads to uncontrolled cell growth which can cause cancer. 

Who is most likely to have a STK11 mutation?

In general, the STK11 mutation is more common in adenocarcinoma non-small cell lung cancer patients with a smoking history but they can be in any patient. It is often but not always in present with a KRAS mutation. STK11 mutations are present in about 10% of patients with lung adenocarcinoma.

How do you know if you have a STK11 mutation?

In general, there are two ways to detect STK11 mutations. The best way is through comprehensive next-generation sequencing (NGS). This type of testing places tissue from a patient’s tumor (gathered from a biopsy) in a machine that looks for a large number of possible biomarkers at one time. There may be some situations where a patient can’t undergo the biopsy needed to perform NGS, and so liquid biopsy is recommended. A liquid biopsy can look for certain biomarkers in a patient’s blood. Talk to your doctor to make sure one of these tests was performed.

Learn more about the different types of biomarker tests here.

Are there different types of STK11 mutations?

Several STK11 gene mutations have been identified that cause inactivation of the STK11 protein.  Researchers are still trying to understand if the different types of STK11 mutations impact treatment options. 

What is the course of treatment like for someone with an STK11 mutation?

The presence of an STK11 mutation does not impact first-line treatment. However, researchers are looking closely at the role immunotherapy in patients with an STK11 mutation. Data show the presence of an STK11 mutation may make immunotherapy less effective.   In the future, STK11 status, along with PD-L1 and TMB levels (other important biomarkers) may help doctors predict which patients will benefit from immunotherapy. 

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

  1. What is the goal of this treatment?
  2. What are the potential side effects?
  3. 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.

Where can I get support?

Page last updated: November 1, 2021

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