Contextualizing T_H17 cells in cancer

The immune system has evolved intricate and sophisticated mechanisms to recognize and eliminate tumours. Among these, T helper 17 (T_H17) cells seem to have a complex role in tumour immunity. Substantial evidence indicates that T_H17 cells can impair the ability of immune cells to kill tumours, but growing research suggests that T_H17 cells may also be crucial for facilitating effective antitumour immune responses. This apparent paradox is likely rooted, at least in part, in the remarkable plasticity of T_H17 cells, which can adopt a range of effector functions depending on the environmental cues present in distinct tissue niches. Understanding the spectrum of functional adaptations that T_H17 cells can undergo is especially important in cancer, where tumours exhibit substantial tissue heterogeneity. Here, we examine the context-dependent roles of T_H17 cells in cancer, with a focus on the environmental signals and regulatory networks that may shape their phenotypes during cancer development and progression. Finally, we discuss how these insights could inform strategies to manipulate T_H17 cells for the development of next-generation cancer immunotherapies.