Transcatheter arterial embolization combined with radiofrequency ablation activates CD8+ T-cell infiltration surrounding residual tumors in the rabbit VX2 liver tumors

Purpose: To evaluate the effect of transcatheter arterial embolization (TAE) combined with radiofrequency ablation (RFA) treatment (TAE + RFA) on the expression of heat shock protein 70 (HSP70) in residual tumors and explore the relationship between the HSP70 and CD8(+) T-cell infiltrate surrounding residual tumors in the rabbit VX2 liver tumor model. Materials and methods: Animals with VX2 liver tumors were randomized into four groups (control, TAE, RFA, and TAE + RFA) with 15 rabbits in each group. Five rabbits in each group were sacrificed on days 1, 3, and 7 after treatment. HSP70 expression and infiltration of CD8+ T-cells in the liver and residual tumors surrounding the necrosis zone were detected by immunohistochemistry staining. The maximal diameters of tumor necrosis, numbers of metastases, and tumor growth rate were compared on day 7 after treatment. Results: TAE + RFA achieved larger maximal diameter of tumor necrosis, lower tumor growth rate, and fewer metastatic lesions, compared with other treatments on day 7. The number of CD8(+) T-cells in the TAE + RFA group was significantly higher than in other groups on days 1, 3, and 7. There was a positive correlation between HSP70 expression level and infiltration of CD8(+) T-cells surrounding the residual tumor on day 1 (r= 0.9782, P= 0.012), day 3 (r= 0.93, P= 0.021), and day 7 (r= 0.8934, P= 0.034). Conclusion: In the rabbit VX2 liver tumor model, TAE + RFA activated the highest number of CD8(+) T-cells surrounding residual tumors. TAE + RFA appears to be a beneficial therapeutic modality for tumor control and antitumor immune response in this model.