VEGFA and retinoblastoma: The co-delivery system specifically and synergistically inhibited the expression of HIF-1α and VEGF in retinoblastoma cells, inhibited the HIF-1α /VEGF/VEGFR signaling pathway, ameliorated the hypoxic microenvironment of the tumors, and hindered the proliferation, migration, and invasion of vascular endothelial cells 65.