PTGS2 and cancer: Many TCM products or single active components have been reported to inhibit a variety of processes in cancer cell growth, invasion, and metastasis by modulating a wide range of molecular targets, including cyclooxygenase-2 (COX-2), nuclear factor kappa B (NF-κB), and nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant signaling pathways.