Effector T cells, primarily CD8+ cytotoxic T lymphocytes (CTLs) and CD4+ helper T cells, are critical for directly targeting and eliminating tumor cells through the release of cytokines such as IFN-γ, TNF-α, and IL-2, and the use of cytotoxic granules containing perforin and granzymes (69). The gene discussed is IL2; the disease is neoplasm.