These large granular lymphocytes provide the body’s major source of interferon-gamma (IFN-γ), a cytokine that is highly important in activating macrophages to kill obligate intracellular pathogens, shaping the immune response of Th1 helper cells, activating antigen presenting cells to enhance upregulation of MHC Class I, and eradicating malignant tumor cells and viruses (8). Here, IFNG is linked to cancer.