IL17A and neoplasm: For example, it has been reported that IL-17, at the tumorigenesis stage, acts as a tumor suppressor involved in recruitment of T lymphocytes and dendritic cells (DCs), promotion of NK cell activity, activation of cytotoxic T lymphocytes (CTLs) and inhibition of Treg repertoire in the tumor milieu [14, 15], whereas in the tumor progression stage, IL-17 inclines to have an oncogenic effect in inhibiting tumor cell apoptosis, impairing antitumor responses and promoting tumor angiogenesis, tumor metastasis and invasion [14, 15].