AIM: To investigate the effect of transcatheter arterial embolization (TAE) on angiogenesis of hepatic tumor.METHODS: Twenty New Zealand White rabbits were randomly divided into two groups of 10 each and VX2 carcinoma was implanted in the left medial lobes of the livers. Fourteen days later, a silicon catheter was inserted into the left hepatic artery of rabbit with VX2 hepatic tumor and infusion was performed via the hepatic artery using Lipiodol (the TAE group) or saline (the control group). Rabbits were sacrificed 7 d after treatment and tumor tissues were excised. Expression of vascular endothelial growth factor(VEGF) protein and microvessel density (MVD) of tumors were examined using immunohistochemistry. The staining intensity of VEGF was evaluated with a computer-assisted image-analyzer. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the VEGF mRNA expression of tumors.RESULTS: MVD was higher in the TAE group compared with the control group (28.6±10.6 vs 16.3±6.9, P＜0.01).Expression of VEGF protein was enhanced after TAE. The staining intensity of VEGF in the TAE group was 0.162±0.018,significantly higher than in the control group (0.142±0.01,P＜0.01). At mRNA level, VEGF165 mRNA was significantly higher in the TAE group compared with the control group(2.58±0.42 vs 1.99±0.21, P＜0.001). MVD was well correlated to VEGF expression in both the TAE group (r=0.69, P＜0.05)and the control group (r=0.72, P＜0.05).CONCLUSION: TAE promotes the development of neovascularization of residual tumors through up-regulation of VEGF expression, possibly due to hypoxic insult.