VEGFA and glioma: In one such study using C6-pTET-VEGF165 xenografts in which VEGF overexpression was switchable under tetracycline regulation in rat glioma cells, Dafni et al employed MRI and confocal microscopy to demonstrate that VEGF overexpression elevated vascular permeability, interstitial convection, and lymphatic drain in the hind limbs of nude mice [15].