Proteomic analysis of hepatitis B virus‐associated hepatocellular carcinoma: Identification of potential tumor markers

Abstract

Hepatocellular carcinoma (HCC) is a malignancy of both underdeveloped and developing countries. Proteomes of ten pairs of clinical hepatitis B virus associated HCC tissue samples were obtained by high resolution two‐dimensional gel electrophoresis. Comprehensive analyses of proteins associated with B‐type HCC were focused on total differentially expressed proteins (≥ two‐fold increase or decrease, Student's t‐test, p < 0.05) from one pair of samples. Protein identification was done by peptide mass fingerprinting with matrix assisted laser desorption/ionization‐time of flight mass spectrometry and liquid chromatography‐tandem mass spectrometry. Comparative analyses of proteins associated with B‐type HCC included repeat statistics in ten cases. A total of 100 protein spots, corresponding to 80 different gene products, were identified. Proteins whose expression levels were different by more than 2‐fold in at least 50% of the cases (five of ten cases) were further analyzed and 45 proteins were selected out as candidates for HCC‐associated proteins. Western blotting further validated up‐regulated expressions of two candidate proteins in tumor tissues: proliferating cell antigen and stathmin 1. This comprehensive and comparative analyses of proteins associated with B‐type HCC could provide useful molecular markers for diagnostics and prognostics and for therapeutic targets. The physiological significance of the differential expressions for several candidate proteins are discussed.