Brain metastases signify a deleterious milestone in the progression of several advanced cancers, predominantly originating from lung, breast and melanoma malignancies, with a median survival timeframe nearing six months. Existing therapeutic regimens yield suboptimal outcomes; however, burgeoning insights into the tumor microenvironment, particularly the immunosuppressive milieu engendered by tumor–brain interplay, posit immunotherapy as a promising avenue for ameliorating brain metastases. In this review, we meticulously delineate the research advancements concerning the microenvironment of brain metastases, striving to elucidate the panorama of their onset and evolution. We encapsulate three emergent immunotherapeutic strategies, namely immune checkpoint inhibition, chimeric antigen receptor (CAR) T cell transplantation and glial cell-targeted immunoenhancement. We underscore the imperative of aligning immunotherapy development with in-depth understanding of the tumor microenvironment and engendering innovative delivery platforms. Moreover, the integration with established or avant-garde physical methodologies and localized applications warrants consideration in the prevailing therapeutic schema.

中文翻译：

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利用免疫疗法治疗脑转移：深入了解肿瘤-脑微环境相互作用和新兴治疗方式


脑转移标志着几种晚期癌症进展中的一个有害里程碑，这些癌症主要源自肺癌、乳腺癌和黑色素瘤恶性肿瘤，中位生存时间接近六个月。现有的治疗方案效果不佳；然而，对肿瘤微环境，特别是肿瘤与大脑相互作用产生的免疫抑制环境的深入了解，表明免疫疗法是改善脑转移的有希望的途径。在这篇综述中，我们精心描绘了有关脑转移微环境的研究进展，力图阐明其发病和演变的全貌。我们总结了三种新兴的免疫治疗策略，即免疫检查点抑制、嵌合抗原受体（CAR）T细胞移植和胶质细胞靶向免疫增强。我们强调必须将免疫疗法的开发与对肿瘤微环境的深入了解结合起来，并建立创新的递送平台。此外，与已建立或前卫的物理方法和本地化应用的整合值得在流行的治疗方案中考虑。