In the presence of tumor cells, or following stimulation with TCR agonists, NKG2D ligands, cytokines (such as IL-12 and IL-18), or DNAM-1 engagement, human γδ T cells produce IFN-γ and TNF-α (21, 56, 94, 106–108). The gene discussed is KLRK1; the disease is neoplasm.