Lung Cancer Biomarker Testing: What You Need to Know
As experts learn more about lung cancer, new diagnostic and biomarker testing options have arisen. Along with typical diagnostic and follow-up tests such as CT scans, lung biopsies, chest X-rays, MRIs, and more, biomarker testing has gained popularity as a way of learning more about why certain cancers develop and how to treat them.1,2
Biomarker testing is a relatively new option, but it may be beneficial for some people with lung cancer, specifically those with non-small cell lung cancer (NSCLC).1,2
What is biomarker testing?
The basic idea behind biomarker testing is to find changes (mutations) within a person's genes. In cancer cells, specific mutations can cause the cells to grow, or proliferate. This leads to further cancer development and spread. Some mutations may help predict the way a cancer will behave as it progresses. This information may also help predict how a cancer might respond to treatment.1,2
Biomarker testing can be done on cells taken in a biopsy. A biopsy is a procedure in which a small collection of cells is taken out of the body and analyzed under a microscope to help diagnose specific types of cancer. These cells can also be further analyzed in a lab to determine their genetic components. This second step is where specific mutations might be identified.1,2
How can biomarker testing affect lung cancer treatment?
Finding out which mutations a person's cancer cells have can greatly affect their treatment plan. It can lead to a personalized plan of attack for their specific cancer. This is sometimes referred to as personalized medicine.1,2
Some mutations may have FDA-approved medicines that are designed to fight that specific cancer. Other mutations may help predict the likelihood of cancer recurrence and suggest the next best steps for treatment planning.1,2
Also, treatments for some mutations are being investigated in clinical trials. Your doctor may be able to connect you with a trial you can join if you are interested.1,2
Examples of mutations that currently have FDA-approved treatments on the market include:1,2
- EGFR mutation (epidermal growth factor receptor)
- KRAS G12C mutation
- ALK gene rearrangement (anaplastic lymphoma kinase)
- ROS1 rearrangement
- HER2 mutation (human epidermal growth factor receptor 2)
- BRAF V600E mutation
- MET alteration
- RET rearrangement
- NTRK gene fusion
In addition to these gene mutations, doctors also test for PD-L1, a protein that can indicate whether immunotherapy is likely to be effective.1,2
Who gets biomarker testing, and what are their results?
According to the 2026 Lung Cancer In America Survey, among 263 respondents with NSCLC, about 41 percent had received some form of biomarker testing. Of these, about 32 percent tested positive for a mutation and 9 percent tested negative.
The most common mutation found in those with NSCLC was an EGFR mutation, affecting about 18 percent of respondents. The next most common was an ALK rearrangement, at about 6 percent, followed by KRAS mutations at about 3 percent and RET rearrangements at about 2 percent.
Respondents were also asked about PD-L1 testing. About 16 percent tested positive for PD-L1 expression at some level, and 6 percent tested negative. About one-quarter had never been tested for PD-L1.
About 10 percent of participants with NSCLC had never been tested for mutations, and about half were unsure whether they had this kind of testing in the past. This suggests that biomarker testing — and PD-L1 testing specifically — may still not be widely used or understood among people with NSCLC.
Talk with your doctor
At this time, people with NSCLC may benefit the most from biomarker testing. Those with squamous cell or small cell lung cancer who have never smoked may also benefit.1,2
But regardless of what kind of lung cancer you have, or your smoking history, you can ask your doctor about biomarker testing and whether it is appropriate in your specific case. Biomarker testing may not benefit everyone, and your doctor can explain why it may or may not be an option for you.
Learn more about biomarker, tumor, and genomic testing:
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