IL17A and hepatocellular carcinoma: Th17 cells can thus promote tumor growth and metastasis.[14] On the other hand, through the secretion of IL-17 and interferon-gamma (IFN-γ), which increase the expression of cytotoxic lymphocytes (CTLs) in the TME, Th17 can inhibit tumor growth.[15] Zhang et al[16] found that the level of Th17 cells in tumor tissues was significantly higher than that in non-neoplastic tissues and that the density of Th17 cells in tumor tissue had a negative linear correlation with the overall survival of patients with HCC.