In contrast to NK cells, T cells recognize targets in an antigen-specific fashion and, once activated, can eliminate cancer cells by various means, including perforin/granzymes, Fas ligand, and cytokines like interferon (IFN)-γ and tumor necrosis factor (TNF)-α; however, their activation requires presentation of the respective antigen by professional antigen-presenting cells (APCs). The gene discussed is IFNG; the disease is cancer.