The interleukin 17 (IL-17) family of cytokines contains 6 structurally related cytokines, IL-17A through IL-17F. IL-17A, the prototypical member of this family, just passed the 25^th anniversary of its discovery. Although less is known about IL-17B–F, IL-17A (commonly known as IL-17) has received much attention for its pro-inflammatory role in autoimmune disease. Over the past decade, however, it has become clear that the functions of IL-17 are far more nuanced than simply turning on inflammation. Accumulating evidence indicates that IL-17 has important context- and tissue-dependent roles in maintaining health during response to injury, physiological stress, and infection. Here, we discuss the functions of the IL-17 family, with a focus on the balance between the pathogenic and protective roles of IL-17 in cancer and autoimmune disease, including results of therapeutic blockade and novel aspects of IL-17 signal transduction regulation.

白细胞介素17（IL-17）细胞因子家族包含6种结构相关的细胞因子，即IL-17A至IL-17F。该家族的原型成员IL-17A刚刚通过了^第25^届发现的周年纪念日。尽管对IL-17B-F知之甚少，但IL-17A（俗称IL-17）因其在自身免疫性疾病中的促炎作用而备受关注。然而，在过去的十年中，已经清楚的是，IL-17的功能远比仅仅启动炎症要细微得多。越来越多的证据表明，IL-17在损伤，生理应激和感染的反应过程中，在维持健康方面具有重要的背景和组织依赖性作用。在这里，我们讨论IL-17家族的功能，重点是IL-17在癌症和自身免疫性疾病的致病作用和保护作用之间的平衡，包括治疗性阻断的结果和IL-17信号转导调控的新方面。