Proteomic analysis on metastasis-associated proteins of human hepatocellular carcinoma tissues

Purpose: A comparative proteomic approach was used to identify and analyze proteins related to metastasis of hepatocellular carcinoma (HCC). Methods: Proteins extracted from 12 HCC tissue specimens (six with metastases and six without) were separated by two-dimensional gel electrophoresis (2-DE). The protein spots exhibiting statistical alternations between the two groups through computerized image analysis were then identified by mass spectrometry. In addition immunohistochemistry (IHC), Western blotting and RT-PCR were performed to verify the expression of certain candidate proteins. Results: 16 proteins including HSP27, S100A11, CK18 were annotated by mass spectrometry, relevant to chaperone function, cell mobility, cytoskeletal architecture, respectively. Most were previously unconnected with metastasis of HCC. Of these HSP27 was found overexpressed consistently in 2-DE patterns of all metastatic HCC tissues compared with nonmetastatic ones. IHC and Western blotting of HCC tissues confirmed this difference while RT-PCR did not. Conclusion: There are various proteins joined together in HCC metastasis. The overexpression of HSP27 may serve as a biomarker for early detection and therapeutic targets unique to the metastatic phenotype of HCC.