Abstract: Objective: To explore the presence of informative protein biomarkers in the human serum proteome of breast cancer. Methods：Serum samples were profiled using iTRAQ technology coupled with LC-ESI-QTOF-MS, and Mascot searching. Western-blotting were used for validation of the candidate biomarkers. Results: 335 proteins were identified, and 23 proteins were associated with breast cancer. Three biomarker candidates generated from iTRAQ experiments were successfully verified using Western-blotting . Conclusion: This study provided a global view of potential mechanisms and potentional biomarkers of breast cancer, and demonstrated that iTRAQ combined with LC-ESI-QTOF-MS quantitative proteomics is a powerful tool for biomarker discovery.

Key words: breast cancer, iTRAQ, proteomics, serum, biomarker