TNF and neoplasm: When we analyzed the tumor-bearing hemisphere of treated animals 1 week after the first i.t. administration of IL-12 compounds, flow cytometric analysis indicated increased infiltration of T cells—particularly of CD4+ T cells—across all IL-12-treated groups; alongside, effector CD4+ T cells, regulatory T cells (Treg) and CD8+ T cells all showed a higher frequency of IFNγ and TNFα expression after IL-12 treatment (Figs. 3K–M and S5), indicative of increased effector functions33 and of heightened, IFNγ-induced Treg fragility34, as described previously during IL-12 therapy of flank tumors35.