Background: The human microbiome plays a crucial role in health and disease. Dysbiosis, an imbalance of microorganisms, has been implicated in cancer development and treatment response, including in primary brain tumors and brain metastases, through interactions mediated by the gut–brain axis. This scoping review synthesizes current evidence on the relationship between the human microbiome and brain tumors.Methods: A systematic search of five electronic databases was conducted by an expert librarian, using controlled vocabulary and keywords. A targeted grey literature search in Google Scholar and clinical trial registries was also undertaken. Eligible studies included primary research involving human patients, or in vivo, or in vitro models of glioma or brain metastasis, with a focus on the microbiome’s role in tumor development, treatment response, and outcomes.Results: Out of 584 citations screened, 40 studies met inclusion criteria, comprising 24 articles and 16 conference abstracts. These included 12 human studies, 16 using mouse models, 7 combining both, and 5 employing large datasets or next-generation sequencing of tumor samples. Thirty-one studies focused on primary brain tumors, six on brain metastases, and three on both. Of the 20 studies examining dysbiosis in tumor development, 95% (n = 19) found an association with tumor growth. Additionally, 71.4% (n = 5/7) of studies reported that microbiome alterations influenced treatment efficacy.Conclusions: Although the role of the gut–brain axis in brain tumors is still emerging and is characterized by heterogeneity across studies, existing evidence consistently supports a relationship between the gut microbiome and both brain tumor development and treatment outcomes.
背景：人体微生物组在健康和疾病中扮演着关键角色。菌群失调，即微生物失衡，通过肠-脑轴介导的相互作用，已被证实与癌症（包括原发性脑肿瘤和脑转移瘤）的发生发展及治疗反应相关。本范围综述旨在整合当前关于人体微生物组与脑肿瘤关系的证据。 方法：由专业文献检索员系统检索五个电子数据库，使用受控词汇和关键词进行检索。同时，在Google Scholar和临床试验注册平台进行了针对性的灰色文献检索。纳入标准包括涉及人类患者、胶质瘤或脑转移瘤体内外模型的原发性研究，重点关注微生物组在肿瘤发生、治疗反应及预后中的作用。 结果：在筛选的584篇文献中，40项研究符合纳入标准，包括24篇论文和16篇会议摘要。其中12项为人类研究，16项使用小鼠模型，7项结合两者，另有5项采用大型数据集或肿瘤样本的新一代测序技术。31项研究聚焦于原发性脑肿瘤，6项关注脑转移瘤，3项涵盖两者。在探讨菌群失调与肿瘤发生关系的20项研究中，95%（n = 19）发现其与肿瘤生长存在关联。此外，71.4%（n = 5/7）的研究报告微生物组改变会影响治疗效果。 结论：尽管肠-脑轴在脑肿瘤中的作用尚处于探索阶段，且现有研究存在异质性，但现有证据一致支持肠道微生物组与脑肿瘤的发生发展及治疗结局之间存在关联。
肿瘤(癌症)患者之家