The analysis of EGFR variants in Chinese adult glioblastoma patients.

Abstract

e14020 Background: Glioblastoma multiforme (GBM) is the most common primary brain tumor with complex genetic alterations and genomic profiles. EGFR amplification occurs in approximately 40% of primary GBM，EGFR mutation is also a prevalent genetic abnormality in GBM. A series of potential therapies targeting EGFR variants are currently in development, such as tyrosine kinase inhibitors (TKIs), monoclonal antibodies, vaccines, etc. However, to date, EGFR-targeted therapy continues to face significant challenges. A deeper understanding of EGFR variant profiles and pathobiology of GBM will be required. Methods: Next-generation sequencing of 131-gene profiling was performed to analyze EGFR activating mutations from 891 Chinese glioma patients in 2019-2020. Somatic mutations and copy number variations were detected following the standard operating procedure (SOP). We screened out the EGFR activating mutation and calculated the mutation frequency and the tumor location. Results: 51 GBM patients had activating mutations. The average age was 49 years (range,25-73 years). Most of the tumors occurred in the cerebral hemisphere (56.9%), followed by ventricles (3.9%) and thalamus (3.9%), etc. 43/51 (84.3%) were accompanied by high-fold EGFR amplification. 9/12 (75%) were EGFR intracellular mutation occurs with EGFR amplification, 31/35 (88.6%) were EGFR extracellular mutation occurs with EGFR amplification. Moreover, 4 patients carried EGFR intracellular and extracellular mutation occurs with EGFR amplification. There was no significant difference between the ratio of intracellular mutations and extracellular mutations with EGFR amplification (P=0.3496). Conclusions: In our GBM patients, EGFR activating mutations were accompanied by high-fold EGFR amplification. As we know that, GBM benefit from EGFR-TKIs may be limited. Therefore, multi-targeted combination therapy research could be considered in the future.