Epidermal growth factor receptor variant III mutation in Chinese patients with squamous cell cancer of the lung

The aim of this study was to investigate the distribution of epidermal growth factor receptor (EGFR)vIII mutation in Chinese non-small cell lung cancer (NSCLC) patients and to explore the likely relationship between EGFRvIII mutation and response to EGFR-tyrosine kinase inhibitors (TKIs) in squamous cell carcinoma (SCC).

Samples were derived from two patient cohorts: (i) 114 early-stage NSCLC who received surgical resection; and (ii) 31 advanced-stage SCC who received EGFR-TKI EGFRvIII. EGFR and V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations were detected by reverse transcription polymerase chain reaction (RT-PCR), denaturing high-performance liquid chromatography, and PCR-restriction fragment length polymorphism, respectively. The associations of EGFRvIII, EGFR, and KRAS mutations with clinical outcome of EGFR-TKI treatment were evaluated using the Kaplan-Meier method, descriptive analysis, and multi-variable Cox regression analysis.

In the first cohort, EGFRvIII mutation was detected in eight of 114 (7.0%) patients, including 11.1% (6/54) SCC and 3.6% (2/55) adenocarcinomas (ADC) (P = 0.269). In the second cohort, five (16.1%) and 10 out of 31 advanced SCC presented EGFRvIII and EGFR mutations, respectively. No appreciable discrepancy of progression-free survival or disease control rate was detected between the patients with and without EGFRvIII mutation (P > 0.05). However, longer median overall survival (OS) was observed in patients harboring EGFRvIII compared to those without EGFRvIII, although the difference did not reach statistical significance.

The frequency of EGFRvIII mutation in SCC was higher than in ADC. SCC patients harboring EGFRvIII mutations had a tendency for prolonged OS.