IL17A and neoplasm: In contrast, some other studies have suggested that increased level of IL-17 in tumor site leads to the improved antitumor immunity of TCD4+IL-17+ cells through inducing Ag-specific cytotoxic T cells (48), while tumor infiltrated Th17 cells per se are not able to kill or inhibit tumor cells proliferation in vitro and conversely, promote tumor progression due to the existence of TGF-β and IL-6 in local tumor site (18).