Tumor-infiltrating IL-17A(+) cells determine favorable prognosis and adjuvant chemotherapeutic response in muscle-invasive bladder cancer

The role of IL-17A(+) cells remains controversial among various cancer types. This study aimed to investigate the effects of IL-17A(+) cells on tumor immune contexture and clinical outcome in muscle-invasive bladder cancer (MIBC). In this study, we enrolled 141 patients from Zhongshan Hospital, 118 patients from Shanghai Cancer Center and 403 patients from TCGA cohort. In vitro studies were conducted in 32 freshly resected tumors. Survival analysis was conducted using Kaplan–Meier and Cox regression analysis. The results suggested that patients with high levels of IL-17A(+) cells had prolonged overall survival and recurrence-free survival (HR = 0.268, P < .001; and HR = 0.433, P < .001). Moreover, these patients tended to be at lower risk of death and recurrence after adjuvant chemotherapy (P = .012 and P = .004). An increased number of IL-17A(+) cells correlated with the infiltration of several anti-tumor immune cells into tumors. In addition, IL-17A(+) cells had an influence on the recruitment, proliferation, and activation of CD8(+) cells, and were positively associated with the expression of several anti-tumor effector cytokines. In conclusion, tumor-infiltrating IL17A(+) cells were correlated with an elevated anti-tumor immunity in MIBC. Besides, high infiltration of IL17A(+) cells can predict benefit from ACT for MIBC patients.