OBJECTIVE Hepatocellular carcinoma (HCC) is a hypervascular tumor for which angiogenesis plays an important role in its progression. The aim of this study was to investigate the expression of TWIST and VEGF and determine their roles in angiogenesis of HCC.METHODS Expression Twist and VEGF mRNA was determined by realtime RT-PCR in 30 pairs of hepatocellular carcinoma and matched noncancerous tissues. Immunohistochemistry was carried out to analyze the protein expression of Twist and VEGF in 40 hepatocellular carcinoma cases. Staining of endothelial cells for CD34 was used to evaluate the microvessel density (MVD).RESULTS We found that the HCC specimens showing positive Twist expression in tumor cells had a higher microvessel density than those without Twist expression. Furthermore, we found that overexpression of the Twist protein positively correlated with up-regulation of VEGF in the HCC tissues (r=0.479, P=0.002).CONCLUSION Our results demonstrate that Twist may play an important role in the angiogenesis of HCC and a high-level of Twist expression may be related to the malignant potential of tumor cells.