IL17A and neoplasm: Notably, CD4+CD25+FOXP3+ (GFP+) T cells can differentiate into Th17 cells in the presence of IL-6 [57] and T helper 17 (Th17) cells, one of the CD4+ T cells, can produce IL-17 to protect against microbial infection [214], while excessive activation of Treg cells suppresses antipathogenic or anticancer immunity, leading to chronic infection and tumor progression [144].