Retrospective Chinese NSCLC study links compound EGFR mutations to poorer TKI response

A single-center retrospective analysis of 452 Chinese patients with non-small cell lung cancer found that tumors with compound epidermal growth factor receptor mutations had poorer clinical responses to first-line tyrosine kinase inhibitors than tumors carrying a single classical EGFR mutation. Patients whose tumors also had co-occurring EGFR mutations likewise exhibited lower sensitivity to these drugs. The investigators reported statistically significant associations for compound mutations (P = 0.022) and co-mutations (P = 0.045), indicating that more complex EGFR mutation profiles were linked to reduced TKI efficacy in the analyzed cohort.

Researchers used next-generation sequencing to screen tumor samples for mutations in EGFR, KRAS, ALK, ROS1, MET, ERBB2, RET, BRAF and NTRK1/2/3. At least one gene alteration was detected in 81.64% of the 452 patients. EGFR mutations were the most frequent genomic alterations, present in 53% of the cohort, followed by KRAS mutations at 13% and ALK mutations at 11%. The investigators classified EGFR mutations into four structural subgroups based on kinase-domain characteristics and sensitivity to tyrosine kinase inhibitors: classical-like, T790M-like, Ex20ins-L and PACC. Among patients with EGFR-mutant tumors, 80.33% carried classical-like mutations, 6.69% carried T790M-like mutations, 3.35% carried Ex20ins-L mutations and 4.60% carried PACC mutations. Within the classical-like category, L858R substitutions accounted for 50% and exon 19 deletions accounted for 46.88%.

The TKI analysis was conducted separately in 28 patients with compound EGFR mutations and 39 patients with EGFR co-mutations. The compound-mutation group had a worse clinical response to first-line TKIs than the group with a single classical EGFR mutation, while the co-mutation group also showed poorer TKI sensitivity, with P values of 0.022 and 0.045, respectively. These observations link compound and co-occurring mutation status with clinical outcomes, but they do not by themselves establish that the additional mutations caused the reduced response. The retrospective design, selection of patients at one center and small mutation-defined subgroups also limit how broadly the results can be generalized.

The analysis additionally evaluated associations between driver-gene mutations and clinicopathological characteristics. EGFR mutation frequency was significantly higher among women and among patients with adenocarcinoma. ALK mutations showed positive correlations with tumor site and lymph-node metastasis, while male patients were more likely to carry RET mutations. Overall, the study found that classical-like EGFR mutations predominated in this Chinese NSCLC cohort and that compound and co-occurring EGFR mutations were associated with poorer TKI response. The authors said the findings may help guide drug development and personalized targeted therapy, although confirmation in larger, independent cohorts would be needed to assess the consistency and clinical significance of the observed relationships.

Subject of Research: Association of compound and co-occurring EGFR mutations with TKI response in a Chinese NSCLC cohort

Article Title: Structural classification of EGFR mutations and its association with TKI efficacy against compound and co-mutations in a Chinese NSCLC cohort: a single-center retrospective analysis

Article References: Liu, R., Xie, X., Yu, D., Huang, F., Yang, H., & Du, H. (2026). Structural classification of EGFR mutations and its association with TKI efficacy against compound and co-mutations in a Chinese NSCLC cohort: a single-center retrospective analysis. BMC Cancer. https://doi.org/10.1186/s12885-026-16912-4

Image Credits: AI Generated

DOI: 10.1186/s12885-026-16912-4

Keywords: NSCLC, EGFR mutations, compound mutations, co-mutations, tyrosine kinase inhibitors, next-generation sequencing, L858R, exon 19 deletion, retrospective cohort, precision oncology, Structural, classification