CD8A and melanoma: Oniki et al. found that the antitumor effect of IL-23 was mediated by CD8+ T cells and IFN-gamma, whereas IL-27 mainly acts through natural killer cells in a mouse melanoma model.25 Lo et al. also documented that the antitumor mechanisms of IL-23 was mainly achieved by CD8+ T cells.29 Another study showed that the administration of IL-23 was successfully associated with significant suppression of fibrosarcoma growth with the therapeutic effects similar to those from IL-12 treatment.