Effect of tumor angiogenesis on rapid progression of residual tumor of liver cancer after radiofrequency ablation / 中华普通外科杂志

ABSTRACT

Objective To explore experimently the effect of tumor angiogenesis on rapid progression of residual tumor of liver cancer after radiofrequency ablation ( RFA). Methods A rabbit VX2 hepatoma model was established. Inoculated tumors were treated by using RFA at 55 ℃ , 70 ℃ and 85 ℃ respectively to establish the residual VX2 hepatoma model. Rabbits implanted with VX2 hepatoma but receiving no RFA treatment served as controls. The expression of vascular endothelial growth factor (VEGF)was determined in tumors to assess the relationship between VEGF and the focal tumor volume and distant metastasis. The expression of VEGF and microvessel density ( MVD) in tumor tissues was assessed by immunohistochemistry. The protein expression of VEGF was assessed by Western blot. The expression of VEGF mRNA was detected by RT-PCR. Results There were significant differences of the local tumor volume between the control group (9.91 ±0.98) cm3 and the other groups (respectively t = -17.43,-10.11, -8.79,all P<0. 05). Compared with the 70 ℃ group (17. 08 ±2. 28 ) cm3 and the 85 ℃ group (15.95 ±4.95) cm3, the focal tumor volume of 55 ℃ group was the largest (21.26 ±2.32) cm3,( respectively t = 4. 69,6. 78, all P<0. 05). Much more metastatic lesions of lung were observed in the RFA treated groups in comparison to the control group. Moreover, the lung metastasis in 55 ℃ group was the most serious among the three RFA treated groups (respectively t = -21.65, -30. 15, all P<0. 05 ).Immunohistochemical staining indicated that the expression of VEGF and MVD in the RFA treated groups was much higher than those in control group ( MVD respectively t = -13.01, -5. 46, -5. 63, all P<0. 05), ( VEGF respectively t = 8. 00,4. 92,4. 21, all P<0. 05 ). Furthermore, the expression of both VEGF protein and VEGF mRNA in 55 ℃ group was the highest among the three RFA treated groups.Conclusions The over-expression of VEGF accelerating the tumor angiogenesis may be one of the mechanisms inducing rapid progression of residual liver tumor after RFA.