Biomarker Resource Center
Lung Cancer Biomarkers
Reviewed by XpertPatient Medical Advisory · Updated June 2026 · Sources: NCI · ACS · ASCO · NIH/PMC
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What is a biomarker?
A biomarker is a signal your cancer leaves behind. Doctors find these signals in your blood or tumor tissue. The signals tell your doctor important things — like what type of cancer you have and how it is behaving.
Think of it like a clue. Your doctor collects clues from your biomarker test results. Those clues help build a picture of your cancer. That picture helps your doctor and you have a more informed conversation about next steps.
Everyone’s cancer is different — even people with the same type of cancer can have very different results. That is why biomarker testing matters. It helps your care team understand your cancer specifically.
For Lung Cancer
Why do biomarkers matter in lung cancer?
Lung cancer treatment has changed a great deal in recent years. Biomarker testing helps your doctor understand the specific makeup of your cancer. That information is an important starting point for the conversation about what approaches may be worth exploring for your situation.
💬 A good question to ask your doctor: If you have been diagnosed with non-small cell lung cancer, ask your doctor whether full biomarker testing has been done. This is commonly recommended before care decisions are made.
The most important lung cancer biomarkers are EGFR, ALK, KRAS, and PD-L1. Together they help your doctor understand the specific makeup of your tumor and which treatment approaches are most worth exploring for your situation.
Patient Poll
Have you had biomarker testing for your lung cancer?
The Tests Your Doctor May Order
🔍 Is there a gene change in your tumor?
EGFR is a gene that, when mutated, can drive lung cancer growth. Testing for EGFR mutations is commonly done for people with non-small cell lung cancer. If this mutation is found, your doctor will talk with you about approaches that may be worth exploring. Ask your doctor whether EGFR testing has been done and what your result means.
🔍 Did two genes join in a way that may affect your cancer?
ALK rearrangements are found in some lung cancers. If your tumor has this finding, your doctor will discuss what that means for your care. Ask your doctor whether ALK testing has been done and what your result means for your situation.
🔍 Is there a common gene mutation in your tumor?
KRAS is the most common mutation found in lung cancer. Knowing whether your tumor has a KRAS mutation — and which specific type — gives your doctor useful information. Ask your doctor whether KRAS testing was included in your biomarker panel and what the result means.
🔍 How does your tumor interact with your immune system?
PD-L1 is a protein that affects how your immune system responds to cancer. Testing your PD-L1 level gives your doctor information that is commonly used when discussing certain care approaches. Ask your doctor what your PD-L1 result means and how it fits into the overall picture.
🔍 Is a protective gene changed in your tumor?
TP53 is a gene that normally helps regulate cell growth. When it is changed, it gives your doctor additional information about your cancer. Ask your doctor whether TP53 was tested and what the result means for your care.
Watch & Learn
Important: This page is for education only. It is not medical advice. Every patient’s situation is different. Please talk to your doctor or care team about what your biomarker results mean for you specifically.
Common Questions
Lung Cancer Biomarkers — Your Questions Answered
Should I ask about biomarker testing?
If you have been diagnosed with non-small cell lung cancer, it is worth asking your doctor whether full biomarker testing has been done. This is commonly recommended before care decisions are made.
What is a liquid biopsy?
A liquid biopsy is a blood test that looks for cancer signals in your bloodstream. Ask your doctor whether a liquid biopsy makes sense for your situation and what it could tell them.
What if my results show no mutations?
If your biomarker testing does not show a specific mutation, your doctor will still have important information to work with. There are commonly used approaches for all lung cancer types. Talk to your doctor about what your results mean for your care.
What is comprehensive genomic profiling?
Comprehensive genomic profiling tests your tumor for many gene changes at once. Ask your doctor whether this type of testing has been done or is worth considering for your situation.
Quick Links
From the Lung Cancer Center on XpertPatient
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