Current studies on IL-17 have focused on its essential role in tumor initiation, development, and regression.277–279 Recent evidence suggests that chronic inflammation may be a predisposing risk factor for many tumors.280,281 Chronic IL-17-induced inflammatory responses are considered as essential factors in mediating cellular carcinogenesis, promoting tumor cell proliferation and metastasis, and inducing immune tolerance in cancer cells. This evidence concerns the gene IL17A and neoplasm.