Objective: To explore the effect of hepatitis B virus X protein on malignant transformation of hepatocytes and its mechanism.
Methods: The total protein content of CCL13-HBx and CCL13-pcDNA3.1 cells was extracted and separated by two-dimensional electrophoresis with immobilized pH gradients (2-DE). The silver-stained 2-DE was scanned with digital image scanner and analyzed with Image Master 2-DE Elite 4.01 software. To obtain peptide mass fingerprint(PMF) of differential protein spots，matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was used. PMF was searched in SWISS-PROT database by Mascot software to identify differential expression proteins.
Results: The clear background, well-resolved and reproducible 2-DE maps  were obtained. from CCL13-HBx and CCL13-pcDNA3.1 cells. Twenty-six protein spots were found as differentially expressed proteins，of which 14 protein spots were identified successfully. The identified proteins were correlated with cell metabolism, cell cycle and signal transduction.
Conclusions: The well- resolved， reproducible 2-DE maps of CCL13-HBx and CCL13 cells have been established and 14 differentially expressed proteins are identified. They provide new clues for the study of hepatocarcinogenesis at protein level.