While ω-3 PUFAs produce prostaglandin E3 (PGE3) in response to COX-1, PGE3 inhibits the proliferation and invasion of tumor cells by downregulating the expression of phospholipase A2 phosphatidylinositol-specific phospholipase C (PI-PLC), nuclear factor (NF-κB), and COX-2. The gene discussed is PTGS2; the disease is neoplasm.