PTGS2 and malignant colon neoplasm: Tammali et al. [354] showed that treatment of the human colon cancer cell line Caco-2 with HNE or HNE-GSH or the aldose reductase-catalyzed product of HNE-GSH, DHN-GSH, resulted in increased cyclooxygenase-2 (COX-2) expression and prostaglandin E2 production.