Objective  This study aimed to detect Rac1 and vascular endothelial growth factor(VEGF) expressions in hepatocellular carcinoma(HCC) and to correlate this expression with tumor angiogenesis.

  Methods  Rac1 and VEGF expressions in 43 specimens of HCC, 43 specimens of adjacent nontumorous liver tissue, and 21 specimens of normal liver tissues were detected by immunohistochemistry. Image analysis software was used to conduct a quantitative analysis of Racl and VEGF expressions by accessing their mean optical density(MOD). Microvascular density(MVD) was determined by labeling the vascular endothelial cells with CD34.

  Results  Rac1 protein expression occurred mainly in the HCC tissue of the cytoplasm. MOD in HCC tissue was markedly higher than those in adjacent nontumorous liver tissue(P < 0.01) and in normal liver tissue(P < 0.01). The expression of VEGF protein was higher in HCC tissue than those in adjacent non-tumorous liver tissue(P < 0.01) and normal liver tissue(P < 0.01). Moreover, the Rac1 and VEGF protein expressions in HCC were positively correlated with MVD(r=0.490, P=0.001;r=0.355, P=0.019). Rac1 protein expression in HCC tissue was positively correlated with the VEGF protein expression in HCC tissue(r=0.583, P=0.000).

  Conclusion  Rac1 possibly promotes tumor angiogenesis through the upregulation of VEGF expression, and is associated with HCC invasion and metastasis.