IL2 and neoplasm: We review some beneficial bacteria that act on DCs, NK cells, cytotoxic T cells, and helper T cells to promote the secretion of the pro-tumor cytokines IFN-1, IFN-γ, and IL-2 and down-regulate the secretion of TNF-α, IL-6, IL-10, and IL-22, thus exerting anti-tumor immune effects.