PTGS2 and neoplasm: In addition, COX-2 is an early gene that is rapidly induced by pro-inflammatory cytokines (interleukin (IL) 1β, IL2 and tumor necrosis factor (TNF)), growth factors (EGF and platelet-derived growth factor (PDGF)), lipopolysaccharides, bile acids, ultraviolet B irradiation and tumor promoters [18–21].