IL-17 is overexpressed in both the tumor cells and tumor microenvironment of patients with malignancies.267,268,282 This differential IL-17 expression between tumorous and healthy tissues suggests that it has a biological role in the development of tumors.283,284 These findings suggest that IL-17-mediated signaling pathways may play essential roles in the transformation of a chronic inflammatory state into a malignant state. The gene discussed is IL17A; the disease is neoplasm.