在过去的十年中，高通量测序技术的进步使我们对微生物群在人类疾病，特别是肿瘤学中的作用的理解发生了质的飞跃。尽管肿瘤内微生物群的生物量较低，但它仍然是肿瘤免疫微环境的重要组成部分，在不同肿瘤组织和个体患者之间表现出显着的异质性。尽管免疫疗法已成为治疗肿瘤的主要策略，但患者对这些治疗的反应差异很大。越来越多的证据表明，肿瘤内微生物群与免疫系统之间的相互作用可以调节宿主肿瘤的免疫反应，从而影响免疫治疗的有效性。因此，深入了解肿瘤内微生物群如何塑造和调节肿瘤免疫微环境至关重要。在此，我们总结了肿瘤内微生物群在癌症免疫中作用的最新进展，探讨了肠道屏障内外肿瘤内微生物群影响免疫功能的潜在机制。我们还讨论了肿瘤内微生物群对癌症免疫治疗反应及其临床应用的影响，强调了该领域未来的研究方向和挑战。我们预计，本综述提供的关于癌症免疫与肿瘤内微生物群之间相互作用的宝贵见解将促进基于微生物群的肿瘤疗法的发展。版权所有 © 2024 Liu、Li、Wu、Guo、Xu、Jin 和 Zhao。

Over the past decade, advancements in high-throughput sequencing technologies have led to a qualitative leap in our understanding of the role of the microbiota in human diseases, particularly in oncology. Despite the low biomass of the intratumoral microbiota, it remains a crucial component of the tumor immune microenvironment, displaying significant heterogeneity across different tumor tissues and individual patients. Although immunotherapy has emerged a major strategy for treating tumors, patient responses to these treatments vary widely. Increasing evidence suggests that interactions between the intratumoral microbiota and the immune system can modulate host tumor immune responses, thereby influencing the effectiveness of immunotherapy. Therefore, it is critical to gain a deep understanding of how the intratumoral microbiota shapes and regulates the tumor immune microenvironment. Here, we summarize the latest advancements on the role of the intratumoral microbiota in cancer immunity, exploring the potential mechanisms through which immune functions are influenced by intratumoral microbiota within and outside the gut barrier. We also discuss the impact of the intratumoral microbiota on the response to cancer immunotherapy and its clinical applications, highlighting future research directions and challenges in this field. We anticipate that the valuable insights into the interactions between cancer immunity and the intratumoral microbiota provided in this review will foster the development of microbiota-based tumor therapies.Copyright © 2024 Liu, Li, Wu, Guo, Xu, Jin and Zhao.