This perspective is supported by the evidence that an efficient immune response is based on a well-defined orchestration of different and interrelated aspects, such as production of effective numbers of cytotoxic T cells with high avidity for tumor antigens, infiltration of CD8+ T cells into the tumor, detection of tumor antigens, and, finally, enhancement of an immune antitumor response [56]. The gene discussed is CD8A; the disease is neoplasm.