IL17A and cancer: In addition to this cytoprotective effect, IL‐22‐producing ILC3 cells sustain colon cancer in a colitis‐associated cancer model of 129SvEv.Rag−/− mice treated with Helicobacter hepaticus and azoxymethane (AOM) (Kirchberger et al., 2013), and some ILC3s also produce pro‐inflammatory cytokines (e.g. IL‐17A, IFN‐γ and GM‐CSF) in response to IL‐23 and other cytokines, such as IL‐1β and IL‐12 (Klose and Artis, 2016), which contribute to intestinal inflammation (Buonocore et al., 2010).