Correlation between Th17 cells and tumor microenvironment

• A development mechanism for Th17 cells in tumor microenvironment is proposed.
• Expression and migration of Th17 cells in tumor microenvironment.
• The balance between IL-17A and IL-17F in regulating tumor angiogenesis.
• The function of Th17 cells relies on the contradictory immune response to tumor.

Since their identification in 2005, T helper (TH)17 cells have been proposed to play important roles in several human diseases, including various autoimmune conditions, inflammations, allergy, and tumors. Focusing on human studies, we review the current understanding of molecular interactions (IL-1β, IL-6, IL-23, IL-21 and TGF-β), the signaling pathway (STAT3 → RORγt) and the migration (induced by CCR6/CCL20) that contribute to Th17 differentiation and function in tumor microenvironment. Furthermore, we also make a synthesis of contradictory conclusions as to the roles that these cells are playing in the process of tumourigenesis in order to provide guidance of Th17-targeted therapy in tumors.