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NRG1 and Lung Cancer

Testing for errors in the NRG1 gene helps your doctor understand your lung cancer and recommend treatments that may work better for you.

NRG1 at a Glance:

  • Errors in the NRG1 gene are one type of lung cancer biomarker.  
  • NRG1 gene fusions are often found in a subtype of non-small cell lung cancer (NSCLC) called invasive mucinous adenocarcinoma.
  • Comprehensive biomarker testing can reveal the NRG1 gene fusion and lead to more treatment options. 

What Is NRG1-Positive Cancer?

NRG1, or neuregulin 1, gene fusions happen when two parts of a cell’s DNA join together, or fuse. This fusion sends signals to the cells to grow abnormally, or mutate, which can lead to cancer cell growth. NRG1 gene fusions can occur in several different types of cancer, including pancreatic cancer and lung cancer.

Why Testing for NRG1 Matters

Biomarker testing is essential for finding out if you have NRG1‑positive lung cancer because NRG1 fusions are rare, hard to detect, and require specific testing methods to identify. Knowing whether NRG1 fusions are present directly affects treatment options and can provide access to emerging 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 Testing for NRG1 Is 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. 

Sometimes, DNA NGS testing alone may miss NRG1 gene fusion, so doctors may also use special laboratory tests that look at the RNA of the cells to identify the fusion partners and confirm that the gene fusion is active.

Learn more about the different types of biomarker tests

Understanding Your NRG1 Test Results

An NRG1‑positive result means your cancer has an NRG1 fusion, a rare genetic change that can drive tumor growth and may make you eligible for specific targeted therapies or clinical trials designed for this biomarker.

An NRG1‑negative result means no NRG1 fusion was found, so treatments that target NRG1‑driven cancers are unlikely to help.

An unclear result means the test couldn’t confirm whether an NRG1 fusion is present, and your care team may recommend repeat or more advanced testing, especially RNA‑based testing, to get a clearer answer. 

How NRG1 Results Influence Treatment

An NRG1 gene fusion result can help guide treatment decisions.

Knowing if you have an NRG1 gene fusion is important no matter your stage of lung cancer. However, it has the most treatment implications for stage IV lung cancer.

Patients with advanced-stage NSCLC whose cancer continues to grow after other treatments may be eligible for a targeted therapy called zenocutuzumab-zbco (Bizengri). This medication is given through an IV.

Other treatment options for NRG1 gene fusions are currently being studied in clinical trials.

If you do not test positive for a biomarker with an approved targeted therapy, traditional chemotherapy, immunotherapy, or a combination of the two may be recommended.

Surgery or radiation may also be recommended.

It may also be appropriate to enroll in a clinical trial looking at treatments for a number of other markers. 

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 NRG1 Diagnosis

Someone with NRG1‑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. 

NRG1 fusions are rare and sometimes hard to detect, so it’s helpful to make sure your testing included both DNA and RNA sequencing to get the clearest picture of your tumor. 

Because NRG1‑positive lung cancer has emerging targeted therapies, it may be useful to talk with your care team about what’s available now and what trials might be a good fit. 

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 NRG1-Positive Lung Cancer

It is important to work closely with your doctor to help monitor your medication side effects. Ask about connecting with a supportive/palliative care doctor at the beginning of your treatment to help ensure your side effects are well managed.

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 19, 2026

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