PTGES and neoplasm: This notion has been established by experimental and epidemiological studies that reported increased expression of cyclooxygenase isoforms (COX-1 and COX-2) and microsomal prostaglandin E synthase (mPGES-1), as well as enhanced levels of PGE2, in several tumor types (colon, breast, prostate, and lung tumors) [17,18,19,21,35].