Biological activities of IFN-g produced by CD4+ T cells have been reported to include the following: 1) enhanced anti-tumor activity through activation/anti-tiredness of CD8+ T cells [12], 2) enhanced inflammatory response through immune cells such as macrophages [13], 3) enhanced antigen presentation to cancer cells and growth inhibition [14], and 4) anti-tumor effects through regulation of the tumor blood vessels [15]. The gene discussed is CD8A; the disease is cancer.