PTGS2 and breast cancer: In breast cancer, cyclooxygenase-2 (COX2), heparin-binding epidermal growth factor-like growth factor (HBEGF) and ST6 N-acetylgalactosaminide alpha-2,6-sialyltransferase 5 (ST6GALNAC5) facilitate endothelial adhesion and BBB transmigration.