Recently, however, several studies have indicated that IL-17A exerts antitumor effects via the immune cells; in IL-17A−/− mice, IFN-g+CD4+ T cells, IFN-g+CD8+ T cells, and IFN-g+ natural killer (NK) cells were found decreased in tumor-draining lymph nodes [30] and IL-17A stimulation of tumor cells resulted in migration of CD3+ T cells and NK cells [31]. This evidence concerns the gene IL17A and neoplasm.