Preliminary Study of Differentially Expressed Serum Peptides of Advanced NSCLC Patients Responsive to EGFR-TKI and Their Clinical Significance

Background and objective This study aimed at using matrix-assisted laser desorption ionization - time of flight mass spectrometer (matrix-assisted laser desorption ionization time-of-flight mass spectrometry, MALDI-TOF-MS) screening the difference serum peptides during epidermal growth factor tyrosine kinase inhibitors (EGFR-TKIs) treatment and exploring their significance of advanced NSCLC patients. Methods Collect 102 serum samples from 34 advanced NSCLC patients, which are before TKI treatment, best effect of treatment and after progession. Peptides were extracted from the samples and then detected by MALDI-TOF-MS system to get the mass spectra. The mass spectra data was analyzed by the ClinproToolTM software to identify the different serum peptides, and then analyzed the clinical significance of peptides. Results Among the 34 patients who received TKI treatment, there were none evaluated as complete response (CR), 11 patients evaluated as PR and 23 patients evaluated as stable disease (SD), with the PFS was 8.0 months (95%CI: 6.6-11.2); overall survival (OS) was 11.4 months (95%CI: 10.6-16.5). After detected the serum from three different points of time, the result showed that they were totally different; 87 different peptide peaks were identified after analysis self-paired serum between the time of best effect and baseline, which included one statistically different [P<0.001, area under curve (AUC)≥0.9] peptide; 96 different peptide peaks were identified after analysis serum between the time of progression and baseline, which included 3 statistically different (P<0.001, AUC≥0.9) peptides; 115 different peptide peaks were identified after analysis serum between the time of progression and best effect, which included 4 statistically different (P<0.001, AUC≥0.9) peptides. Conclusion Theserum peptides of NSCLC patients in the process of TKI treatment are dynamic and the different peptides may be associated with treatment effect and disease progression. However, the features and clinical significance of different peptides need to be validated in the future.