^(125)I粒子植入放疗对前列腺癌免疫微环境影响的初步分析

Effect of iodine-125 brachytherapy in prostate cancer on immune microenvironment

目的:探讨^(125)I粒子植入放疗对前列腺癌免疫微环境的影响。方法:利用免疫组织化学技术检测、比较cT1~3N0M0期前列腺癌行^(125)I粒子植入治疗前、后前列腺癌细胞PD-L1表达情况,以及肿瘤微环境中CD3^(+)T、CD4^(+)T、CD8^(+)T、PD-1^(+)T细胞的表达情况变化。结果:前列腺肿瘤细胞PD-L1阳性表达率为55.6%(35/63);肿瘤组织中均可见CD3^(+)、CD4^(+)、CD8^(+)T细胞浸润;55.6%的组织中可见PD-1^(+)T细胞表达,但数量较少;经^(125)I粒子植入治疗后行经尿道前列腺切除术的前列腺癌组织中,肿瘤细胞PD-L1表达率明显上调95.8%(22/23),而且表达强度也增加。结论:前列腺癌肿瘤微环境中均可见浸润性T淋巴细胞,但肿瘤抗原特异性T细胞很少;^(125)I粒子植入放疗可以促进前列腺癌患者的肿瘤免疫反应,但具有一定时间窗;联合免疫检查点阻断治疗是合理的,或许也很有必要。

Objective:To evaluate the effects of iodine-125permanent brachytherapy on prostate cancer immune microenvironment.Methods:Immunohistological analyses and comparison of the expression of PD-L1and tumor infiltrating lymphocytes(TILs,CD3^(+),CD4^(+),CD8^(+),PD-1^(+))on tissue sections between archival prostate biopsy samples and corresponding TURP or RP were performed for≤cT_(3) prostate cancer patients before receiving brachytherapy.Results:PD-L1were expressed in 55.6%(35/63)cases,and tumor-infiltrating T lymphocytes were seen in all cases.PD-1^(+)T cells were seen in 55.6%cases,but with very small density.After brachytherapy,CD3^(+),CD4^(+),CD8^(+)T cells were increased significantly.PD-1^(+)T cells had a moderate raise,and the expression of PD-L1on PCa cell significantly raised.Conclusion:All PCa had TILs expression in cancer immune microenvironment,but may be not tumor antigen-specific T-cell.Iodine-125permanent brachytherapy can stimulate anti-tumor immunity in a particular time window,and when combined with immunotherapy(Immune Checkpoint Inhibitors),it’s reasonable,even necessary.