Fig. 8.

A hypothetical schematic of the equilibration of free (unbound) drug delivery between plasma (blood) and tumor sites (flank or orthotopic tumor). (A) The movement of free drugs in the absence of the blood-tissue barrier in PDX mice with flank xenograft and in the presence of the BBB in PDX mice with orthotopic xenograft. (B) Relative BBB integrity throughout the brain bearing GBM tumor. (C) Relatively restricted free drug delivery to the growing edge (BAT) of orthotopic tumor and resultant GBM invasion throughout the rest of the brain. MRI, magnetic resonance imaging.