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. Author manuscript; available in PMC: 2020 Mar 20.
Published in final edited form as: Semin Immunol. 2019 Mar 20;41:101271. doi: 10.1016/j.smim.2019.03.003

Figure 1. Direct and indirect effects of ILCs on cancer.

Figure 1.

ILCs have both pro and anti-tumorigenic effect. ILC1s and NK cells block tumor cell growth through IFN-γ secretion. NK cells also lyse tumor cells through secretion of perforin and granzymes. IL-13 and amphiregulin secreted by ILC2s enhance MDSC and Treg functions respectively, facilitating immune evasion of tumors. ILC3 help maintaining a diverse microbiota and induce CD4 T cell tolerance for commensal bacteria, preventing dysbiosis and chronic inflammation that create a pro-tumorigenic microenvironment. Species in a healthy microbiota can also augment anti-cancer therapy. However, ILC3s can promote tumor growth by excessive secretion of IL-22. Through inappropriate release of IL-17, ILC3s also contribute to chronic inflammation that promotes tumorigenesis. Products from microbiota enhance TLR activation, which can promote or inhibit tumors depending on the context.