Intratumoral CD8+ cytotoxic T cells play an important role in tumor-killing activity by interacting with tumor antigens and causing direct or indirect cell lysis mediated by cytokines such as interferon-γ, tumor necrosis factor α (TNFα), and granulocyte-macrophage colony-stimulating factor (GM-CSF) [49]. The gene discussed is CD8A; the disease is neoplasm.