PTGS2 and cancer: Among them, ω-6 PUFAs (arachidonic acid) can bind to cyclooxygenase 2 (COX-2) to produce PGE2 and enhance cancer cell invasion; ω-3 PUFAs (eicosapentaenoic acid) can bind to cyclooxygenase 1 (COX-1) to produce PGE3 and inhibit the activity of COX-2, reduce the production of PGE2, and inhibit cancer cell invasion (16).