[Role of gut microbiota in carcinogenesis and treatment for colorectal cancer].

Colorectal cancer is one of the most common malignant tumors of digestive tract. There are a large number of microorganisms in the digestive tract. Under normal physiological conditions, intestinal microorganisms can help with digestion and absorption, resist pathogen invasion and regulate the proliferation of intestinal mucosal cells. However, intestinal microflora imbalance will affect the intestinal microenvironment and intestinal cell function, and is closely related to the incidence and progression of colorectal cancer. Firstly, this paper introduces the changes of intestinal flora in patients with colorectal cancer, and then summarizes the mode of intestinal flora participating in the occurrence of colorectal cancer from the macro level. Then, we elaborate the involvement of intestinal flora in colorectal cancer from the aspects of cytokine-dependent chronic inflammation, DNA damage of intestinal epithelial cells, carcinogenic metabolites of intestinal flora and cellular enzymes, and changes of intestinal immune system. The pathogenesis of colorectal cancer provides a reference for further study of the pathogenesis of colorectal cancer. Finally, from the perspective of intestinal flora and colorectal cancer treatment, we analyze the significance of probiotics and bacterial flora transplantation for the treatment of colorectal cancer, and provide some new treatment ideas and methods that may be useful for the treatment of colorectal cancer.结直肠癌是最常见的消化道恶性肿瘤之一。人体肠道内存在大量的微生物，正常生理状态下，肠道微生物将有助于肠道对食物的消化吸收，抵抗病原体入侵和调节肠道黏膜细胞的增殖；但肠道菌群失调会影响肠道内部微环境和肠道细胞功能，并且与结直肠癌的发病及疾病进展密切相关。本综述通过介绍结直肠癌患者肠道菌群的改变，从宏观层面总结肠道菌群参与结直肠癌发生的作用模式，并从细胞因子依赖性慢性炎性反应、肠道上皮细胞DNA损伤、肠道菌群代谢产物和细胞酶致癌，以及肠道内免疫系统的改变等几个方面总结肠道菌群参与结直肠癌发病的作用机制，为进一步研究结直肠癌的发病机制提供参考。最后，从肠道菌群治疗的角度，分析益生菌和菌群移植对于结直肠癌治疗的作用，为结直肠癌的治疗提供一些新的治疗理念和方法。.