PTGS2 and pancreatic neoplasm: Recent studies have also implicated cycloxygenase 2 (COX-2, the inducible form of cycloxygenases, enzymes involved in conversion of arachidonic acid to prostaglandin) (Hughes et al., 2005) and trefoil factor 1 (TFF1) (Arumugam et al., 2011) (a stable secretory protein that is upregulated in pancreatic cancer but not expressed in the normal pancreas) in PSC proliferation in response to cancer cell secretions.