Site Editor
Gregory J. Riely, MD, PhD
Gregory J. Riely, MD, PhD
Posted: Monday, May 12, 2025
More than 10% of rare, molecular variants of EGFR mutations are overlooked with multigene testing, according to the results of a study published in Thoracic Cancer. Among patients with non–small cell lung cancer (NSCLC), patients with EGFR mutations in exons 18 to 21 have shown substantial benefit from targeted treatment with EGFR tyrosine kinase inhibitors, but only when their mutations are identified.
Investigators from Japan analyzed the number of mutations missed with Oncomine Dx Target Test Multi-CDx System (ODxTT) testing, which is the most widely used genetic test for NSCLC in Japan. A total of 418 patients with NSCLC underwent molecular testing using the ODxTT, 267 of which had adenocarcinoma. No mutations were found in 82 patients. Investigators re-analyzed the BAM (binary alignment map) files for these patients, looking for rare EGFR alterations to determine if ODxTT had overlooked any actionable variants.
Mutations in EGFR exons 19 and 18 were identified in six and four patients, respectively, through the re-analysis. Five of these patients were treated with EGFR tyrosine kinase inhibitors, with three of these patients achieving a partial response and one achieving stable disease. The fifth patient showed progressive disease.
The study authors, led by corresponding author Takayuki Takahama, MD, PhD, of the Genome Medical Center and Department of Medical Oncology, Kindai University Faculty of Medicine, Osaka, Japan, advocated for comprehensive genomic profiling early on for all patients with NSCLC who are suspected of having EGFR mutations.
Disclosure: For full disclosures of the study authors, visit Thoracic Cancer.
JNCCN Spotlights
