Objective: To determine whether biomarkers which can be identified in the plasma are predictive for response to EGFR-TKIs and patient survival time.Methods: Formalin-fixed and paraffin-embedded biopsies from tumor tissues and paired plasma samples were collected from 134 patients with advanced NSCLC.EGFR mutations in both types of specimens were assessed by ARMS/Scorpion assay.Expression levels of transforming growth factor-alpha and beta one (TGF-α and TGF-β 1) were assessed using enzymelinked immunosorbent assay.Concentrations of circulating freeDNA were determined in both NSCLC patients and healthy subjects by colorimetric assay.The clinical significance of EGFR mutations, levels of cytokines, and circulating free DNA was assessed in advanced NSCLC patients treated with EGFR-TKIs.