Clinical significance of pretreatment plasma biomarkers in advanced non-small cell lung cancer patients

Background The use of biomarkers for selecting non-small cell lung cancer (NSCLC) patients for treatment with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) is essential. The aim of this study was to explore whether biomarkers detected in plasma were predictive for response to EGFR-TKIs and survival time of NSCLC patients. Methods Tumor tissues and paired blood were collected from 134 advanced NSCLC patients treated with EGFR-TKIs. EGFR mutations in both types of specimens, and expression of transforming growth factor-alpha and beta one (TGF-α and TGF-β1) were assessed in NSCLC patients. Concentrations of circulating free DNA were detected in plasma from both NSCLC patients and healthy subjects. The clinical significance of EGFR mutations, levels of cytokines, and circulating free DNA was assessed in advanced NSCLC patients. Results EGFR mutations were detected in 68 tumor samples and 17 plasma samples of 134 NSCLC patients. The concentrations of circulating free DNA were higher in NSCLC patients than in healthy subjects. Patients with high TGF-β1 level showed shorter overall survival and worse response to EGFR-TKIs than patients with low TGF-β1 level. Conclusions Plasma levels of TGF-β1 may be a marker for predicting response to EGFR-TKIs and survival time in NSCLC patients.