IL17A and neoplasm: Although the role of Th17 cells co-producing IL-17 and IFN-γ is not clear, it has been suggested that both cytokines can either synergistically or independently induce the production of functionally diverse chemokines within the tumor environment which in turn can recruit and promote distinct types of effector T cells and/or other immune cells that can influence antitumor immune responses and mediate tumor regression or progression (Kryczek et al., 2009b; Martin-Orozco et al., 2009; Kesselring et al., 2010).