Brain cancers carry bleak prognoses, with therapeutic advances helping only a minority of patients over the past decade. The brain tumour microenvironment (TME) is highly immunosuppressive and differs from that of other malignancies as a result of the glial, neural and immune cell populations that constitute it. Until recently, the study of the brain TME was limited by the lack of methods to de-convolute this complex system at the single-cell level. However, novel technical approaches have begun to reveal the immunosuppressive and tumour-promoting properties of distinct glial and myeloid cell populations in the TME, identifying new therapeutic opportunities. Here, we discuss the immune modulatory functions of microglia, monocyte-derived macrophages and astrocytes in brain metastases and glioma, highlighting their disease-associated heterogeneity and drawing from the insights gained by studying these malignancies and other neurological disorders. Lastly, we consider potential approaches for the therapeutic modulation of the brain TME.

脑癌的预后很暗淡，在过去的十年里，治疗方法的进步只帮助了少数患者。脑肿瘤微环境（TME）具有高度免疫抑制性，并且由于构成它的胶质细胞、神经细胞和免疫细胞群而不同于其他恶性肿瘤。直到最近，由于缺乏在单细胞水平上对这一复杂系统进行解卷积的方法，对大脑 TME 的研究还受到限制。然而，新的技术方法已经开始揭示 TME 中不同神经胶质细胞和骨髓细胞群的免疫抑制和促肿瘤特性，从而确定新的治疗机会。在这里，我们讨论脑转移瘤和神经胶质瘤中小胶质细胞、单核细胞源性巨噬细胞和星形胶质细胞的免疫调节功能，强调它们与疾病相关的异质性，并借鉴通过研究这些恶性肿瘤和其他神经系统疾病获得的见解。最后，我们考虑大脑 TME 治疗调节的潜在方法。