Lung Cancer Biomarkers
All newly diagnosed non-small cell lung cancer patients should have comprehensive biomarker testing — EGFR, ALK, KRAS, and PD-L1 together determine whether targeted therapy or immunotherapy is the right approach.
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 measurable signal — like a gene mutation — found in your tumor. In lung cancer, biomarker testing can find a specific change in your tumor’s DNA that a targeted drug is designed to block.
Lung cancer treatment has changed more in the last 15 years than almost any other cancer. Today, if your tumor has the right mutation, you may take a targeted pill at home instead of IV chemotherapy — with better results and fewer side effects. Every newly diagnosed lung cancer patient should have full biomarker testing before treatment starts.
What this means for you: The key question biomarker testing answers: does your tumor have a mutation that a targeted drug can block? If yes, that drug may work better than chemotherapy.
The Tests Your Doctor Orders
🔍 Is there a mutation that a targeted daily pill can block?
EGFR mutations are found in about 15% of lung cancers. If you have one, pills like osimertinib (Tagrisso) may work better than chemotherapy and cause fewer side effects. Taken at home, once a day.
🔍 Did two genes join in a way that drives cancer growth?
ALK rearrangements are found in about 5% of lung cancers — more often in younger patients and non-smokers. ALK inhibitors like alectinib work very well against ALK-positive tumors.
🔍 Is there a common driver mutation in your tumor?
KRAS is the most common lung cancer mutation. A specific version called KRAS G12C can now be targeted with sotorasib (Lumakras) — a major recent breakthrough. Ask if your KRAS subtype has been identified.
🔍 Will immunotherapy help your immune system fight the cancer?
PD-L1 is a protein cancer uses to hide from your immune system. Testing your PD-L1 level tells your doctor whether immunotherapy drugs like pembrolizumab (Keytruda) are likely to work for you.
🔍 Is a key protective gene damaged?
TP53 normally helps stop cancer from forming. When it’s mutated, cancer can grow more aggressively. Your doctor uses TP53 status as one signal among many when planning treatment.
Watch & Learn
Common Questions
Lung Cancer Biomarkers — Your Questions Answered
Do all lung cancer patients need biomarker testing?
Yes — if you have non-small cell lung cancer, full biomarker testing is recommended before any treatment starts. If this hasn’t been done, ask your doctor to order it now.
What if my tumor has no targetable mutations?
About 30–40% of lung cancers don’t have a currently targetable mutation. Immunotherapy (based on PD-L1 level) or chemotherapy are the main options. New targeted therapies are being approved regularly — ask about clinical trials.
What is a liquid biopsy?
A blood test that detects cancer DNA in your bloodstream. It’s useful when getting a tissue biopsy is difficult, or to monitor whether the cancer is developing new mutations during treatment.
What is comprehensive genomic profiling?
A single test that checks your tumor for hundreds of mutations at once. It can find rare mutations that standard panels miss — potentially opening doors to more treatment options or clinical trials.
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Visit the Lung Cancer Center → Full Biomarkers Guide →
