Overexpression of CYB5R2 in NPC cells inhibits angiogenesis and VEGF expression. a Hematoxylin and Eosin (H&E) staining of xenografts in paraffin-embedded sections with tumors from the CAM model. Black arrows point to microvessels around the tumor. b Immunohistochemical staining of VEGF in xenografts from the CAM model. Empty vector-transfected CNE2 and HONE1 cells are positive for VEGF. c Enzyme-linked immunosorbent assay (ELISA) of secreted VEGF protein in supernatant from CYB5R2- or empty vector-transfected CNE2 and HONE1 cells. d Real-time PCR analysis of the relative mRNA level of hypoxia-induced factor alpha (HIF-1α) in CYB5R2- or empty vector-transfected CNE2 and HONE1 cells. Data are presented as mean ± SD of three experiments. *P < 0.05.