CD8A and melanoma: MSCs intravenously injected 24 h after melanoma induction significantly enhanced the cytotoxicity of CD8+ CTLs and NK cells, increased the production of anti-tumorigenic cytokines (TNF-α, IFN-γ, IL-17) in tumor-infiltrated CD4+ Th1 and Th17 lymphocytes and attenuated melanoma growth and progression.