Abstract: Objective: To seek differentially expressed serum proteins related to stage I non-small cell lung cancer (NSCLC). Methods: The sera of lung cancer group were collected and balanced mixed from 6 patients who were surgically and pathologically diagnosed as stage I NSCLC in Tianjin chest hospital from September 2011 to November 2011. Those of control group were collected and balanced mixed from 15 healthy subjects in the corresponding period. Two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) were employed to screen and identify differentially expressed serum proteins between the two groups. Results: Two-dimensional electrophoresis (2-DE) patterns of serum proteins with high-resolution and reproducibility were successfully obtained from sera of the two groups. The average protein spots were 330±12. One hundred and twenty eight significantly differentially expressed protein spots between the two groups were screened with PDquest software．Ten proteins were successfully identified via peptide mass fingerprinting using MALDI-TOF-MS. Among them, 7 proteins were overexpressed, including alpha-1-acid glycoprotein, C1 inhibitor, angiotensinogen, transferrin, transthyretin, inter-alpha-trypsin inhibitor heavy chain H2 and ficolin-3. Whereas three proteins were underexpressed, including fibronectin, complement C4-A and complement C3. Conclusion: Four differentially expressed proteins close related to cancer can be separated and identified initially in the sera of patients with stage I NSCLC by 2-DE and MALDI-TOF-MS, which may serve as candidate biomarkers for early detection of NSCLC.

Key words: lung neoplasms, non-small cell, electrophoresis, gel, two-dimensional, MALDI-TOF-MS, proteomics, 血清