Upon activation, NK cells may exert anti-cancer effector functions via direct lysis of cancer cells or indirect cytotoxic responses by secreting cognate ligands [e.g., tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)] for death receptors or pro-inflammatory cytokines [e.g., interferon-gamma (IFN-γ)]. The gene discussed is IFNG; the disease is cancer.