结直肠癌（CRC）是全球第三大常见癌症，其发生主要是由于多年来遗传和表观遗传变化的积累。大量证据表明，肠道微生物群在结直肠癌的发生、进展和控制中发挥着重要作用，具体取决于有益微生物和病原微生物之间的平衡。尽管如此，肠道微生物群组成通过调节宿主免疫反应可能会促进或抑制结直肠癌。因此，肠道微生物群的改变可能会影响免疫疗法的临床结果。先前的研究表明，益生菌、益生元和后生元等治疗策略可以增强肠道免疫系统并提高免疫治疗药物的疗效，可能作为癌症免疫治疗的补充策略。这篇综述讨论了肠道菌群在结直肠癌发生和发展中与免疫反应相关的作用。此外，我们还关注控制肠道微生物组的策略对免疫反应和结直肠癌免疫治疗疗效的影响。我们证明，操纵肠道微生物组可以通过下调 Treg 细胞和其他免疫抑制细胞同时改善肿瘤内 T 细胞的功能来增强免疫反应和免疫治疗的结果；然而，需要进一步的研究，尤其是临床试验来评估其在癌症治疗中的功效。© 2024。作者获得 Springer Science Business Media, LLC（Springer Nature 旗下公司）的独家许可。

Colorectal cancer (CRC), the third most common cancer worldwide, develops mainly due to the accumulation of genetic and epigenetic changes over many years. Substantial evidence suggests that gut microbiota plays a significant role in the initiation, progression, and control of CRC, depending on the balance between beneficial and pathogenic microorganisms. Nonetheless, gut microbiota composition by regulating the host immune response may either promote or inhibit CRC. Thus, modification of gut microbiota potentially impacts clinical outcomes of immunotherapy. Previous studies have indicated that therapeutic strategies such as probiotics, prebiotics, and postbiotics enhance the intestinal immune system and improve the efficacy of immunotherapeutic agents, potentially serving as a complementary strategy in cancer immunotherapy. This review discusses the role of the gut microbiota in the onset and development of CRC in relation to the immune response. Additionally, we focus on the effect of strategies manipulating gut microbiome on the immune response and efficacy of immunotherapy against CRC. We demonstrate that manipulation of gut microbiome can enhance immune response and outcomes of immunotherapy through downregulating Treg cells and other immunosuppressive cells while improving the function of T cells within the tumor; however, further research, especially clinical trials, are needed to evaluate its efficacy in cancer treatment.© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.