Differential Expression Of VEGF And COX-2 In HBV-related And Non-HBV-related Hepatocellular Carcinoma

【objective】Hepatocellular carcinoma is one of the most common malignancies worldwide and the third leading cause of death in China. About 80% of the HCC is associated with HBV infection, and it has been shown that incidence of HCC in patients with HBsAg positive is 100 times higher than in those with HBsAg negative. HCC is a highly vascularized tumor and angiogenesis plays a critical role in the development and invasion, which is important for HCC metastasis and reoccurrence. VEGF (vascular endothelial growth factor) and COX-2 (cyclooxygenase-2) play critical role in the development and progression of HCC. It has been shown that overexpression of VEGF and COX-2 is correlated with HCC invasion and prognosis, but it's not clear whether the expression of VEGF and COX-2 in HCC with HBV infection is different from those without HBV infection. Therefore, understanding the relationship between HBV infection and the expression level of VEGF and COX2 in HCC can further our understanding of the molecular mechanisms for HCC arising from different etiology and provide experimental evidences for the early diagnosis and treatment of HCC.【Methods】1. HCC tissue samples were obtained from the 56 surgical resected HCC confirmed by pathology in our hospital from year 1996-2002. The tissues samples were separated into two groups, with HBV infection or without HBV infection which was determine by the serology and immunohistochemistry analysis of HBsAg.2. VEGF and COX-2 expression was determined by immunohistological staining on the sections from the HCC tissue samples using the quick MaxVisionTM immunohistochemical method. The statistical analysis with theχ~2 test and Spearman Rank Order Correlation was used to determine the relationship of between VEGF and COX-2 overexpression and HBV infection.3. Two cell lines, HeG2 and HeG2.215 with stable HBV expression were cultured and total RNA was isolated from these cells. The expression of VEGF and COX-2 in these two cell lines was determined by RT-PCR.【Results】1. Rapid Immunohistochemical staining shows that (1) the positive rates in VEGF and COX-2 in the HBV infected group were 78.9% and 76.3% respectively, which were higher than the group without HBV infection (50.0% and 44.4% respectively). The difference between the two groups is statistically significant (P < 0. 05). (2)VEGF positive tumors were also positive with COX-2 and the correlation analysis shows that the expression of COX-2 and VEGF is positively correlated (r=0.429,P<0.05)2. Eletrophoresis of the RT-PCR products showed that VEGF and COX-2 expression in HepG2.215 cells was significantly higher than the HepG2 cells (P<0.05)【Conclusion】1. This study showed that the expression of VEGF and COX-2 in the HCC with HBV infection was significantly higher than those without HBV infection, suggesting that HBV infection upregulates the expression of VEGF and COX-2 in HCC. The overexpression of VEGF and COX-2 will promote angiogenesis in the tumors, thus enhance the proliferation and growth of the tumors, which will lead to tumor invasion and metastasis.2. The expression of VEGF and COX-2 in HepG2.215 cells is significantly higher than the HepG2 cell, which is consistent with the immunohistochemical analysis and highly suggests that HBV infection correlates with VEGF and COX-2 overexpression. This is important for understanding the mechanisms for the HCC development and progression after HBV infection.3. The differential expression of VEGF and COX-2 in HCC with or without HBV infection suggests a significant difference in clinical manifestation and outcome between the HCC with HBV infection and that without HBV infection and provides directions for the prevention and treatment of HCC of different etiology.