As an immediate-early response gene, PTGS2 is typically undetectable in most cells but is rapidly induced at inflammatory sites by stimuli such as pro-inflammatory cytokines (IL1A/B, IFNG, TNFα) released from inflammatory cells, as well as by tumor promoters like TPA and RAS, both in vitro and in vivo [90,91]. This evidence concerns the gene PTGS2 and neoplasm.