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

BACKGROUND: 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). METHODS: 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. RESULTS: 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. CONCLUSION: The frequency of EGFRvIII mutation in SCC was higher than in ADC. SCC patients harboring EGFRvIII mutations had a tendency for prolonged OS.