Abstract
Background: Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) significantly enhance the median survival of patients with lung adenocarcinoma (ADC) that harbor EGFR-sensitive mutations. However, most patients inevitably experience tumor relapse owing to drug resistance. We aimed to identify potential serum biomarkers for predicting post-EGFR-TKI treatment relapse in patients with advanced-stage lung ADC. Methods: Among 27 patients, including 6 and 21 with early and late relapse, respectively, differentially expressed proteins between patients with early and late relapses were identified using liquid chromatography and tandem mass spectrometry and subsequently validated using Western blotting. Predictive ability was assessed using the receiver operating characteristic curve and area under the curve (AUC) analysis. The association between the clinical variables and treatment response was evaluated using the chi-square test. Results: The serum expression levels of the translocated promoter region (TPR), junction plakoglobin (JUP), and fibrinogen alpha chain (FGA) were significantly higher in patients with late rather than early relapse. The findings indicated that TPR and FGA exhibited good diagnostic performance, with AUCs of 0.946 (p = 0.002; 95% confidence interval [CI], 0.84-1.05) and 0.809 (p = 0.034; 95% CI, 0.65-0.97), respectively. Conclusions: Our results suggest that the TPR and FGA levels are potential predictors of post-EGFR-TKI treatment relapse.