Donate
Call the Lung HelpLine
Ask a Question
The following text field filters the results that follow as you type. Use Tab to access the results.
  1. Home
  2. Lung Health & Diseases
  3. Lung Disease Lookup
  4. Lung Cancer
  5. Symptoms & Diagnosis
  6. Biomarker Testing
  7. NTRK

NTRK and Lung Cancer

Testing for NTRK gene fusions helps your doctor understand your lung cancer and recommend treatments that may work better for you.

NTRK at a Glance:

  • Errors in the NTRK gene are one type of lung cancer biomarker.  
  • Although NTRK gene fusions are rare, identifying them is important because effective targeted treatments are available for patients whose lung cancer has this biomarker.
  • To find out if you have NTRK gene fusions, you can ask for comprehensive biomarker testing at diagnosis or if treatment stops working. 

Frequently Asked Questions about Biomarker Testing

What Is an NTRK Gene Fusion?

In a tumor with an NTRK gene fusion, a piece of the NTRK gene fuses, or joins, with a piece of another, unrelated gene. This fusion activates the NTRK gene in a way that causes uncontrolled cell growth and cancer. 

NTRK gene fusions can occur in many different types of cancer, but they are rare in lung cancer, found in less than 1% of all lung cancer cases.  Even though they are uncommon, it is very important to know if you have one, because there is an effective treatment available for patients whose lung cancer has NTRK gene fusions. 

Who is more likely to have an NTRK gene fusion?

Currently, research has not shown any specific patient group of demographic that is most, or more, likely to have an NTRK gene fusion. This means that anyone with lung cancer could have these fusions, so testing is recommended for all patients.

In this video, Dr. Robert Doebele explains what an NTRK gene fusion is in cancer. This video was produced in 2020. For the latest treatment options, speak with your doctor.

Video transcript

Why NTRK Biomarker Testing Matters

Biomarker testing is essential for NTRK‑positive lung cancer because NTRK gene fusions are rare, often missed without advanced testing, and directly determine whether a patient can receive highly effective TRK‑targeted therapies. 

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 NTRK 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 gene fusions is usually done using next‑generation sequencing (NGS) of DNA and RNA, which can identify many different fusion partners and confirm whether a fusion is present. 

Learn more about the different types of biomarker tests. 

Understanding Your NTRK Test Results

An NTRK fusion result means your cancer has an NTRK gene fusion, a rare change that can drive tumor growth and may make you eligible for highly effective TRK‑targeted therapies.

An NTRK‑negative result means no NTRK fusion was found, so TRK‑targeted treatments are unlikely to help.

An unclear result means the test couldn’t confirm whether an NTRK fusion is present, and your care team may recommend repeat or more advanced testing, especially RNA‑based testing, to get a more accurate answer.

How NTRK Results Influence Treatment

A positive NTRK gene fusion result can help guide treatment decisions.

Knowing if you have an NTRK gene fusion is important no matter your stage of lung cancer. However, it has the most treatment implications for stage IV patients.

Currently, the approved targeted therapies for NTRK gene fusions in lung cancer are:

  • Entrectinib (Rozlytrek)
  • Larotrectinib (Vitrakvi)
  • Repotrectinib (Augtyro)

These drugs are given in pill form and work by directly targeting, or inhibiting, the gene fusion that is making the cancer grow.

Other treatment options for patients with NTRK gene fusions may include clinical trials, chemotherapy or chemotherapy plus immunotherapy.

Watch as Dr. Robert Doebele explains how NTRK gene fusions are treated (video).

It is important to know that NTRK gene fusions are different than NTRK mutations. 

A fusion is when two genes join, and a mutation is a change in the gene sequence. Think of DNA like words in a book, a fusion is two words stuck together, while a mutation is words out of order. 

Both fusions and mutations can cause uncontrolled cell growth which can lead to cancer, but currently, only NTRK gene fusions have treatments available. 

Treatment for NTRK mutations is still being studied in clinical trials. 

Researchers are also examining if patients who have an NTRK gene fusion who later develop an NTRK mutation are less likely to respond to the NTRK-inhibitor drugs.

All NTRK patients should ask their doctors about clinical trials.

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 NTRK Diagnosis

Someone with NTRK‑positive lung cancer diagnosis 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. 

NTRK fusions are rare, so it helps to make sure your testing included broad next‑generation sequencing (NGS), especially RNA‑based testing, which is best at finding these fusions.

If you have an NTRK fusion, you may be eligible for highly effective treatments like TRK inhibitors or new therapies being studied in clinical trials; your care team can explain which options fit your situation.

Keeping notes on how you feel helps your team support you, adjust treatment if needed, and make sure your care aligns with your goals and preferences. 

Support for People with NTRK-Positive Lung Cancer

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

Freedom From Smoking Clinic - Portsmouth, OH
Portsmouth, OH | Aug 13, 2026 LUNG FORCE Walk - Cleveland
Cleveland, OH | Sep 27, 2026
See All Events