NRG1 fusions testing: what it means for you

Waiting on test results can feel like one more hard thing, for you and the people who love you. Here's what the NRG1 fusions test looks for and how it can help your care team pick the treatment most likely to work for you.

ℹ️ General information to help you and your loved ones talk with your care team, not medical advice. Read our disclaimer.

Matters most in: Lung cancer

The quick guide

What the test looks for: A fusion of the NRG1 gene, where part of NRG1 joins another gene. It's rare (well under 1 in 100 non-small cell lung cancers) and is best found with an RNA-based gene panel on tumor tissue.

Why it matters

NRG1 fusions can drive cancer growth through the HER2 and HER3 pathway. Finding one can open the door to a targeted antibody made for these cancers, so it's worth asking whether your testing looked for it, especially if no other driver was found.

Treatments it can point to

Bizengri (zenocutuzumab), an antibody FDA-approved (accelerated approval) for advanced NRG1 fusion-positive non-small cell lung cancer after earlier treatment

Only your care team can say which treatment fits you. Drug approvals depend on cancer type, stage and prior treatment.

Tissue vs. blood testing

Tumor tissue, ideally with an RNA-based panel, because DNA-only tests can miss fusions.

Most tests use a piece of tumor tissue from a biopsy or surgery. Some can also use a blood sample (a 'liquid biopsy') that looks for tumor DNA floating in the blood. Blood tests are easier and faster, but they can miss a change that a tissue test would find, so a negative blood test is often followed by a tissue test.

❓ Questions you and your loved ones can ask

Did my testing include NRG1 fusions, using RNA?
Is a targeted drug or clinical trial an option for me?
When will my results be back, and will treatment wait for them?
Will my insurance cover this test?

Written by the Cancer Side Effects Guide team from FDA labels and leading cancer centers. Not medical advice. · Last updated: October 15, 2026 · How we write

Not medical advice. This page is general information to help you talk with your care team. It can't replace advice from your doctor or nurse. If you have a fever of 100.4°F (38°C) or higher during treatment, or any symptom that worries you, call your care team now. In an emergency, call 911.

Sources

Last updated: October 15, 2026. We summarize these sources in our own words.