Objective To investigate the early metastasis-associated proteins in sentinel lymph node (SLN) of colorectal cancer.Methods SLN and normal lymph nodes (NLN) were collected from forty-three cases.Hydrophobic protein samples were extracted from individual-matched NLN and SLN of colorectal cancer.Differentially expressed protein spots were detected by two-dimensional electrophoresis and image analysis,and subsequently identified by matrix assisted laser desorption/ionization-time of flight mass spectrometry-mass spectrometry (MALDI-TOF-MS).Metastasis-concerned proteins were selected for further study by western blotting and immunohistochemistry staining.Results Forty proteins were differentially expressed between NLN and SLN,and 4 metastasis-concerned proteins highly expressed in SLN were identified to be hnRNP A1,Ezrin,tubulin β-2C and Annexin A1.Significant difference for these 4 proteins between NLN and SLN was confirmed by western blotting and immunohistochemistry staining.Conclusion Different proteins ware expressed between NLN and SLN.Increased expression of hnRNP A1,Ezrin,tubulin β-2C and Annexin A1 in SLN suggests a significantly elevated early colorectal cancer metastasis