[Mechanism of IL-17 in colorectal inflammation-cancer transition]

Colitis associated colorectal cancer is a common intestinal malignant tumor, secondary to chronic enteritis. The persist existence of various inflammatory cells and cytokines in chronic inflammation promotes the development process of colitis-cancer transition. Interleukin 17 (IL-17) family, produced by Th17 cells, is found to be very important proinflammatory cytokines in various immune responses. In the proinflammatory response, IL-17 plays an important role in the activation and recruitment of neutrophils. Studies have shown the increased expression of IL-17 in serum and tumor tissues of patients with colorectal cancer. Th17 cells can induce the generation of immunosuppressive mediators including TGF-β, CXCR3, CCR6 and IL-6, which promotes the incidence of colorectal cancer. We summarized the role of IL-17 in the occurrence and progression of chronic colorectal inflammation to colorectal cancer, and elaborated the mechanisms by which IL-17 influences the formation of tumor microenvironment, promotes the proliferation, invasion and metastasis of tumor cells, and escapes immune surveillance.