The IL‐17 family of cytokines consists of six groups: IL‐17A, IL‐17B, IL‐17C, IL‐17D, IL‐17E and IL17‐F, which are involved in the development of autoimmunity, inflammation, tumours, host defences against bacterial and fungal infections, and mucosal host defence mechanisms.36, 37. Here, IL17F is linked to neoplasm.