REL and melanoma: Figure 5A shows that activation of NK cells with IL-15, IL-2, or melanoma tumor cells induces the release of pro-inflammatory cytokines, TNF-α, GM-CSF, and IFNγ in WT NK cells. Compared to WT NK cells, c-Rel-/- NK cells release less TNF-α, GM-CSF, and IFNγ upon activation with IL-15, IL-2, and B16F10 tumor cells (Figure 5A). The immune suppressive cytokine IL-10 is slightly increased in c-Rel-/- NK cells upon IL-15 and B16F10 tumor cell activation compared to WT NK cells (Figure 5A).