TNF and neoplasm: However, the induction of MDSC activity in tumor lesions is provided by pro-inflammatory molecules such as interferon (IFN)-γ, IL-1β, IL-4, Tumor necrosis factor (TNF)-α, toll-like receptor (TLR) ligands, prostaglandin (PGE) E2 and is mediated by STAT1, STAT6 and nuclear factor (NF)-κB transcription factors [31,40,42].