VEGFA and glioma: The breakdown of the BBB in glioma has been well-documented because brain tumors secret high concentrations of soluble factors such as vascular endothelial growth factors (VEGF) and matrix metalloproteinases (MMP), which compromise endothelial tight junctions, degrade proteoglycans in the surrounding extracellular matrix, and then allow the infiltration of various immune cells and blood-derived factors [3, 8, 9].