MALDI-TOF-MS analysis in low molecular weight serum peptidome biomarkers for NSCLC

Lung cancer is one of the leading causes of death from cancer in the world. Screening new serum biomarkers is important for the early detection of lung cancer. The purpose of this study was to investigate the serum peptide model between non-small cell lung cancer (NSCLC) patients and healthy controls, as well as between paired pre- and postoperative NSCLC patients, and to find the low molecular weight (LMW) potential tumor markers for NSCLC.

56 serum samples from NSCLC patients, 56 controls, and 20 matched pre- and postoperative patients were analyzed using magnetic-bead (MB)-based purification technique combined with MALDI-TOF-MS. To distinguish NSCLC from cancer-free controls, three models were established. Finally, comparing the three groups of serum protein fingerprints, nano-liquid chromatography-electrospray ionization tandem mass spectrometry was used to further identify the differential peptides.

Among the three models constructed, the GA model had the best diagnostic efficacy. Five differential peaks were screened by combining the case group, healthy controls, and postoperative group analysis, which were up-regulated in the case group and showed a tendency to return to healthy control values after surgery. The protein matching the mass spectrometry peak m/z 2953.73 was identified as fibrinogen α chain.

This study shows that the application of MALDI-TOF-MS is a promising approach for the identification of potential serum biomarkers for NSCLC, which is potentially valuable for establishing a new diagnostic method for lung cancer. In addition, we found that fibrinogen α chain may be an auxiliary diagnostic indicator for NSCLC.