IL17A and cancer: In contrast, Zitvogel’s group showed in several subcutaneous tumor lines that early cancer infiltration by IL-17-producing γδ T cells is required for optimal tumor colonization of IFN-γ-producing CD8+ T cells and therapeutic efficacy of anticancer chemotherapy, in a mechanism requiring IL-1R1 and IL-1β, thus implying a beneficial role of IL-17-producing γδ T cells in anti-tumor defense (Ma et al., 2011; Mattarollo et al., 2011).