The decreased induction of Ptgs2 (encoding COX-2) and Ptges (encoding PGE2 synthase (mPGES-1)) in Pla2g3−/− mice relative to Pla2g3+/+ mice implies that the tumor-associated production of PGE2, a pro-tumorigenic prostanoid6–8, is reduced by the lack of sPLA2-III. This evidence concerns the gene PTGES and neoplasm.