Targeted Therapies Drive Demand for Comprehensive Biomarker Testing in NSCLC

The non–small cell lung cancer (NSCLC) treatment paradigm has welcomed the addition of numerous targeted therapies over the past several years, prompting a complementary increase in molecular testing rates and innovative tumor sequencing methods. However, persisting barriers to testing, such as tissue insufficiency, emphasize the need for increased diligence through repeat biopsies and improved testing alternatives such as liquid biopsies, according to lung cancer experts interviewed by OncLive®.

“[Now] couldn’t be a more important time to do biomarker testing in patients with lung cancer,” Benjamin P. Levy, MD, said.

Levy is the clinical director of medical oncology at the Johns Hopkins Sidney Kimmel Cancer Center at Sibley Memorial Hospital and an associate professor of oncology at Johns Hopkins University School of Medicine in Washington, DC.

What is the prevalence of biomarker testing in NSCLC?

Levy explained that in his practice, it is standard to perform molecular testing in all patients with nonsquamous NSCLC, regardless of stage, as a growing collection of clinical data has demonstrated that those test results are often instrumental in guiding treatment decisions. He noted that historically, testing was not considered mandatory in patients with squamous NSCLC due to a lack of known actionable mutations in that disease subtype. However, he emphasized that more recent research has revealed the presence of targetable mutations in patients with squamous disease. Therefore, the NCCN clinical practice guidelines for the treatment of NSCLC now state that molecular testing for alterations in genes such as EGFR, ALK, KRAS, ROS1, BRAF, NTRK1/2/3, MET, RET, HER2, and NRG1 should be conducted through broad molecular profiling.1 

What Types of Molecular Testing Should Be Performed in Patients With NSCLC?

Although DNA-based next-generation sequencing (NGS) has long been the standard platform for biomarker testing, the incorporation of RNA-based testing has risen to the forefront of best practices, according to Levy.

“The world has changed with the detection of fusions, and these fusions are better interrogated and unearthed with RNA-based testing,” Levy said.

Joel Neal, MD, PhD, added that DNA-based testing may not always report the presence of large gene rearrangements, further advocating for the use of RNA-based assays.

Neal is a professor of medicine in the Division of Oncology at the Stanford Cancer Institute at Stanford University in Palo Alto, California.

“RNA-based assays, where we’re looking at the mRNA product that’s already been made by the cells, and then looking at those RNA sequences, are a lot more sensitive for finding ROS1 gene rearrangements, ALK [rearrangements], and all other rearrangements, too,” Neal said.

Thusly, obtaining testing results requires the use of a tissue-based platform that analyzes both DNA and RNA, the experts explained.

Beyond NGS, Levy emphasized that patients with advanced-stage disease should also undergo immunohistochemistry testing for PD-L1 expression, HER2 expression, and MET amplification to determine their eligibility for FDA-approved therapies.

“We're understanding a lot more about NSCLC than we ever did, and [this is] leading toward more effective and more personalized treatments,” Neal noted.

What is the role of liquid biopsy in lung cancer molecular testing?

Tissue-based testing in every patient with NSCLC has and continues to be the gold standard that all oncology practices are recommended to follow, Levy noted. However, the historical reliance on tissue alone has resulted in untested patients due to insufficient tissue quantities and financial barriers, the experts noted. For instance, the retrospective MYLUNG consortium pragmatic study, which evaluated real-world biomarker testing patterns in The US Oncology Network, found that among patients with metastatic NSCLC, although NGS testing rates were low compared with the rates of testing for individual biomarkers, this rate increased from 33% to 45% from 2018 to 2020 (P < .0001).2

“Even under the best circumstances, when you get a large piece of tissue, either with a fine-needle aspiration or a core biopsy, there are times where there's just not enough…tissue to allow for appropriate, comprehensive NGS,” Levy explained.

The scenario of inadequate tissue is where the role of blood-based assays play critical importance, Levy said. He explained that in the absence of tissue-based results, plasma genotyping may reveal actionable markers and inform patient care.

Furthermore, Neal noted that liquid biopsy can be a useful tool for verifying biopsy results or performing repeat testing.

“We should be able to believe any positive assay, but in a patient without a smoking history and without another oncogenic driver that we've identified, I'll always go looking more and more,” he said. “[I will] probably do RNA-based testing and tissue-based testing if it hadn't been done before to try to make sure we're not missing something. Because these [targeted therapies] are so effective, we can't afford to have a patient who we don't know we can use them in.”

However, Neal noted that liquid biopsy assays are sometimes not as sensitive as tissue-based tests, especially when detecting RNA gene rearrangements. Therefore, striving to obtain adequate samples from repeat tissue biopsies should be a priority when enough tissue has not been obtained in the past.

“I have a patient who was treated with chemotherapy and other options for almost 10 years in the metastatic setting, and we kept trying to get more tissue and couldn't,” he said. “Eventually, a couple years ago, a repeat biopsy was able to get enough tissue and found a ROS1 gene rearrangement. Be persistent [with testing], even if it's many, many years after initial diagnosis.”

What additional barriers to biomarker testing remain for patients with lung cancer?

Although several targeted agents have received FDA approval for select patients with NSCLC who are found to have actionable alterations based on biopsy results, ensuring patient access to testing and therapy at every point in the diagnosis and treatment pathway is crucial, according to Christian Rolfo, MD, PhD. He highlighted that this needs to be a global initiative to ensure testing and therapeutic opportunities are not missed due to financial or regulatory constraints.

Rolfo is the director of the Division of Medical Oncology at The Ohio State University Comprehensive Cancer Center—James and a professor at The Ohio State University College of Medicine in Columbus.

“[As much as we need to] have access to the testing, [we need to] equally have access to the drugs,” Rolfo explained. “In the United States, we are very privileged that we have access to these drugs that are approved by FDA. However, that is not the reality in other countries. [We should be] trying to make these barriers around the globe erased. That is the idea to capture more patients who can get the benefits of these drugs.”

What are best practices for multidisciplinary biomarker testing?

Levy emphasized that implementing and sustaining successful biomarker testing practices at any institution starts with a dedicated “physician champion” who can create institution-wide testing standards and oversee the process from beginning to end.

“Sometimes the test is just not done,” Levy noted. “Oftentimes, it'll sit in pathology or, unfortunately, is just never ordered, either by the medical oncologist or the pathologist. Also, there is a tremendous amount of challenges with coordination and getting those results back. Even when the test is done and it's sent out, having it in the electronic medical record ready to [be used in clinic] can be a challenge.”

Levy’s recommendations for how institutions can bridge these gaps include setting standards for optimal tissue procurement, including communication between medical oncologists and interventional radiologists, interventional pulmonologists, and surgeons about choosing optimal tissue samples in a given patient. From there, institutions should create guidelines for how to act on the results.

How might AI help address barriers to biomarker testing in NSCLC?

As the molecular testing field advances, new technologies may play a role in further personalizing test results and alleviating some of the barriers to more widespread testing practices. For instance, artificial intelligence (AI) stands out as an evolving asset, experts noted.

“AI is pretty unique,” Levy said. “AI, in and of itself, may help us better define the right biomarkers for lung cancer outside of the ones we already have. AI I view as being able to interrogate the tissue in different ways and come up with unique ways to potentially treat it. AI also may help us get answers with smaller amounts of tissue. Maybe tissue insufficiency will get a little better when AI is at play.”

Rolfo also emphasized opportunities for AI use at diagnosis and any other time when patients undergo biopsies.

“The integration of, for example, digital pathology [may play a role in] distinguishing these patients quickly,” he reported. “There are already several initiatives working in diagnostics…based on simple technologies [that may allow us to] have access [to test results] quickly with a rapid test for treatment [eligibility]. This is speeding up the process…from the diagnosis to the drug that is crucial to get results.”

Levy also foresees a potential role for AI in identifying barriers to molecular testing within individual institutions and streamlining standard operating procedures to mitigate some of the organizational issues that lead to delayed or missed testing opportunities.

Rolfo concluded that although testing barriers remain, improvements in testing strategies and accessibility will continue to move the needle in the development of targeted therapies that may in turn bolster the NSCLC treatment paradigm.

“For a common disease that, some years ago, we were using a few drugs in, we have nowadays a rare [set of] diseases that [represent] a fraction of different tumors, characteristics, and different populations that make this disease much more chronic, [but also] much more easy to treat in these populations,” he said. “[We] hope that in the future, [there is] brilliant research coming [that will] continue this fascinating success we are having with targeted therapies.”

References

1. NCCN. Clinical Practice Guidelines in Oncology. Non-small cell lung cancer, version 8.2025. Accessed September 18, 2025. https://www.nccn.org/professionals/physician_gls/pdf/nscl.pdf
2. Robert NJ, Espirito JL, Chen L, et al. Biomarker testing and tissue journey among patients with metastatic non-small cell lung cancer receiving first-line therapy in The US Oncology Network. Lung Cancer. 2022;166:197-204. doi:10.1016/j.lungcan.2022.03.004