Because the discovery of adaptive immune responses against cancer and IFN-γ–mediated tumor rejection (8), the field has overwhelmingly characterized CD8+ cytotoxic T lymphocytes (CTLs) and CD4+ Th1 cells, both of which produce IFN-γ, as T-cell subsets that mediate anti-tumor immunity (94). The gene discussed is IFNG; the disease is neoplasm.