Their function in tumor immunosurveillance is thought to be threefold, firstly by promoting antitumor response by other parts of the immune system, e.g., NK cells and CD8+ T cells, through IFNγ secretion, secondly by hindering macrophage tumor promotion, and thirdly by direct killing of malignant cells and other cells in the tumor microenvironment (26, 27). This evidence concerns the gene IFNG and neoplasm.