Role of interleukin (IL)-17 and T-helper (Th)17 cells in cancer

•IL-17 have been found to exert a pro- or anti-tumourigenic effect in cancer.•Th17 cells are related to other IL-17-Producing Cells.•Th17-associated cytokines in tumor give impetus to tumor progression, or inducing angiogenesis and metastasis.•The balance between Th17 cells and Treg cells play the effective role in tumor Context as well as Th17/Th1 plasticity.

Interleukin-17 (IL-17), a pleiotropic proinflammatory cytokine, is reported to be significantly generated by a distinct subset of CD4+ T-cells, upgrading cancer-elicited inflammation and preventing cancer cells from immune surveillance. T-helper (Th)17 cells produced from naive CD4+ T cells have recently been renowned and generally accepted, gaining eminence in cancer studies and playing the effective role in context of cancer. Th17 cells are the main source of IL-17-secreting cells, It was found that other cell types produced this cytokine as well, including Group 3 innate lymphoid cells (ILC3), δγT cells, invariant natural killer T (iNKT) cells, lymphoid-tissue inducer (LTi)-like cells and Natural killer (NK) cells. Th17-associated cytokines give impetus to tumor progression, or inducing angiogenesis and metastasis. This review demonstrates an understanding on how the pro- or antitumor function of Th17 cells and IL-17 may change cancer progression, leading to the appearance of complex and pivotal biologic activities in tumor.