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. The gene discussed is IL17A; the disease is cancer.