PTGS2 and central nervous system cancer: Thus, the stimulation of cyclooxygenase-2/prostaglandin E2 and metalloproteinase-9 via ROS-activated ERKs is involved in the invasion/migration of U87 glioma cells elicited via TPA and antioxidative substances such as quercetin, baicalein, and myricetin, causing the suppression of invasion/migration processes in glioma cells.