 The blood-brain barrier BBB is an intricate barricade composed of three distinct cell types: brain endothelial cells, pericytes, and astrocyte foot processes. While molecules that are small and lipophilic may easily traverse the BBB, large 180 Daltons andor hydrophilic particles require active transport, or receptor mediation. Specifically, the BBB integrity and degree of permeability is regulated by the capillary endothelial cells in response to astrocytic signals. The strength of intercellular junctions ex. tight junctions, adherins amongst endothelial cells also plays a major role in permeability. Therefore, modulation of all these paracellular properties may serve a large part in decreasing BBB integrity and thus improving drug penetration to the tumor bed. 