Epidermal Growth Factor Receptor Aberrations Identified by Next-Generation Sequencing in Patients with Metastatic Cancers

Purpose The epidermal growth factor receptor (EGFR) is a therapeutic target with confirmed clinical efficacy for several cancer types. We aimed to identify EGFR aberrations and their associations with other genomic alterations in patients with metastatic diseases of various cancers. Materials and Methods We used real-world data from the next-generation sequencing (NGS) of 3,286 patients with metastatic cancer at the Samsung Medical Center. We analyzed the distribution of EGFR amplification, mutation, and fusion, as well as their correlations with microsatellite instability (MSI), tumor mutation burden (TMB), and other gene aberrations. Results A total of 3,286 patients were tested using NGS of a panel covering 523 cancer-related genes (TSO500, Illumina) as part of clinical practice between October 2019 and October 2022. Patients with lung cancer and gliomas were not included in the analysis. Of the 3,286 patients, 175 (5.3%) had EGFR amplification, 38 (1.2%) had EGFR mutations, and eight (0.2%) had EGFR fusion. All 175 patients with EGFR amplifications had microsatellite-stable tumors, but 102 had co-amplifications in other cancer-related genes, and 78 had mutations with clinical significance (tier I/II). Among the 38 patients with EGFR mutations, three (8%) showed MSI-high status, and 11 (29%) demonstrated high TMB (≥ 10 mutations/Mb). Among eight patients with EGFR fusion, three exhibited possible functionalities of the EGFR gene. Conclusion EGFR aberrations, mainly amplification, followed by mutation and fusion, were present in 6.4% of patients with metastatic solid tumors.