微生物广泛存在于人体各个器官中，在众多生理和病理过程中发挥着重要作用。然而，由于污染和生物量低等多种限制因素，目前对瘤内微生物组的了解是有限的。肿瘤内微生物组通过参与体内代谢反应、调节癌症相关信号通路以及影响宿主细胞功能和免疫系统来发挥促肿瘤或抑肿瘤作用。需要强调的是，肿瘤内微生物在不同肿瘤类型的组成和丰度方面表现出很大的异质性，从而可能影响肿瘤发生、进展和转移的各个方面。这些发现表明肿瘤内微生物组作为诊断和预后生物标志物具有巨大的潜力。通过操纵瘤内微生物来进行癌症治疗，可以增强化疗或免疫疗法的疗效，同时最大限度地减少副作用。在这篇综述中，我们全面描述了各种人类实体瘤中瘤内微生物组的组成和功能。结合最新研究进展，我们讨论了瘤内微生物组临床应用的起源、机制和前景。版权所有 © 2023。由 Elsevier B.V. 出版。

Microbes are widely present in various organs of the human body and play important roles in numerous physiological and pathological processes. Nevertheless, owing to multiple limiting factors, such as contamination and low biomass, the current understanding of the intratumoral microbiome is limited. The intratumoral microbiome exerts tumor-promoting or tumor-suppressive effects by engaging in metabolic reactions within the body, regulating signaling cancer-related pathways, and impacting both host cells function and immune system. It is important to emphasize that intratumoral microbes exhibit substantial heterogeneity in terms of composition and abundance across various tumor types, thereby potentially influencing diverse aspects of tumorigenesis, progression, and metastasis. These findings suggest that intratumoral microbiome have great potential as diagnostic and prognostic biomarkers. By manipulating the intratumoral microbes to employ cancer therapy, the efficacy of chemotherapy or immunotherapy can be enhanced while minimizing adverse effects. In this review, we comprehensively describe the composition and function of the intratumoral microbiome in various human solid tumors. Combining recent advancements in research, we discuss the origins, mechanisms, and prospects of the clinical applications of intratumoral microbiome.Copyright © 2023. Published by Elsevier B.V.