Besides our previous finding that PTGR2, an enzyme degrading 15-keto-PGE2, modulates cell death and tumor transformation of gastric cancer cells [18], recent studies also showed an emerging role of 15-PGDH, an enzyme generating 15-keto-PGE2, as a tumor suppressor in different cancers [55–60]. Here, PTGR2 is linked to neoplasm.