PTGER2 and neoplasm: PTGS2 (COX-2) is an immediate-early response gene normally absent from most cells but is induced mainly at sites of inflammation in response to inflammatory stimuli including pro-inflammatory cytokines such as IL1A/B, IFNG, and TNF (TNFalpha) produced by inflammatory cells as well as tumor promoters such as tetradecanoyl phorbol acetate (TPA) and RAS in vitro and in vivo [20,21].