SERPINF1 and nasopharyngeal carcinoma: The authors also investigated the underlying mechanisms that suggested that during the normalization window, Endostar might increase the pericyte coverage of NPC tumor vessels via upregulation of a powerful endogenous anti-angiogenic and antitumor factor-Pigment epithelium-derived factor (PEDF) and downregulation of VEGF, thus inhibiting VEGF signaling that can be attributed to the local increase in oxygenation and decrease in tissue necrosis and edema.