AIM:To identify the differential proteins associated withcolorectal cancer genesis and hepatic metastasis.METHODS:Hydrophobic protein samples were extractedfrom normal colorectal mucosa,primary cancer lesion andhepatic metastatic foci of colorectal cancer.With two-dimensional electrophoresis and image analysis,differentially expressed protein spots were detected,andthe proteins were identified by matrix assisted laserdesorption/ionization-time of flight-mass spectrometry andpeptide mass fingerprint analysis.RESULTS:Significant alterations of the proteins in numberand expression levels were discovered in primary cancerand hepatic metastatic foci,the expression of a number ofproteins was lost in 25-40 ku,but protein spots wasincreased in 14-21ku,compared with normal mucosa.Ninedifferentially expressed protein spots were identified.Threeproteins expressed in normal mucosa,but lost in primarycancer and hepatic metastasis,were recognized ascalmodulin,ribonuclease 6 precursor and mannosidase-αProapolipoprotein was expressed progressively from normalmucosa to primary cancer and hepatic metastasis.Thedifferentially expressed protein of beta-globin was found innormal mucosa and hepatic metastatic tumor,but lost inprimary cancer lesion.Cdc 42,a GTP-binding protein,wasidentified in hepatic metastasis.The protein spots of C4from primary cancer,M7 and M9 from hepatic metastasishad less homology with the proteins in database.CONCLUSION:Variations of hydrophobic protein expressionin colorectal cancer initiation and hepatic metastasis aresignificant and can be observed with two-dimensionalelectrophoresis.The expression of calmodulin,ribonuclease6 precursor and mannosidase-α is lost but the expressionof proapolipoprotein is enhanced which is associated withcolorectal cancer genesis and hepatic metastasis.Cdc 42and beta-globin are expressed abnormally in hepaticmetastasis.Protein C4,M7 and M9 may be associated withcolorectal cancer genesis and hepatic metastasis. AIM: To identify the differential proteins associated with colorectal cancer genesis and hepatic metastasis. METHODS: Hydrophobic protein samples were extracted from normal colorectal mucosa, primary cancer lesion and hepatic metastatic foci of colorectal cancer. Two-dimensional electrophoresis and image analysis, differentially expressed protein spots were detected, and the proteins were identified by matrix assisted laser desorption / ionization-time of flight-mass spectrometry and peptide mass fingerprint analysis. RESULTS: Significant alterations of the proteins in numberand expression levels were discovered in primary cancerand hepatic metastatic foci, the expression of a number of proteins was lost in 25-40 ku, but protein spots was created in 14-21ku, compared with normal mucosa. Ninedifferentially expressed protein spots were identified. Threeproteins expressed in normal mucosa, but lost in primary cancer and hepatic metastasis, were recognized ascalmodulin, ribonuclease 6 precursor and mannosidase -αProapolipoprotein was expressed progressively from normalmucosa to primary cancer and hepatic metastasis. Diagnosed protein of beta-globin was found innormal mucosa and hepatic metastatic tumor, but lost in primary cancer lesion. Cdc 42, a GTP-binding protein, wasidentified in hepatic metastasis. The protein spots of C4 from primary cancer, M7 and M9 from hepatic metastasishad less homology with the proteins in database. CONCLUSION: Variations of hydrophobic protein expression in colorectal cancer initiation and hepatic metastasis are notificant and can be observed with two-dimensionalelectrophoresis. The expression of calmodulin, ribonuclease6 precursor and mannosidase-α is lost but the expression of proapolipoprotein is enhanced with is colorectal cancer genesis and hepatic metastasis. Cdc 42 and beta-globin are expressed abnormally in hepatic metastasis. Protein C4, M7 and M9 may be associated with colorectal cancer genesis and hepatic metastasis .