Differential proteomic analysis of human hepatocellular carcinoma tissues with different metastasis potentials

Objective To comparatively study the differential expression of protein profiles of human hepatocellular carcinomas (HCCs) and portal vein tumor thrombi (PVTT) ,and screen key molecules related to HCC metastasis and recurrence. Methods Proteins extracted from 6 liver tumor tissue specimens (3 HCCs and 3 PVTT) were separated by two-dimensional gel electrophoresis (2-DE). Comparative analyses of 2-DE protein patterns between the two groups were done using computerized image analysis. Selected proteins exhibiting statistically significant alternations were identified by mass spectrometry. Immunohistochemistry and RT-PCR were performed to examine the expression of the candidate proteins. Results Ten proteins including Ki-67, MTHSP75, and NM23 were identified using mass spectrometry. Of these, Ki-67 was found to be over-expressed in 2-DE maps of the PVTT when compared to the HCCs. Immunohistochemistry and RT-PCR of HCC tissues confirmed this difference. Clinicopathological correlation analysis revealed that Ki-67 over-expression in PVTT was significantly associated with positive venous infiltration. Conclusion These are different proteins working together that affect the metastasis of HCCs. The over-expression of Ki-67 may play an important role in metastasis of HCCs. Key words: Carcinoma, hepatocellular; Portal vein; Proteome; Ki-67