Chemotherapeutic drugs are generally not very effective against GBM, partly due to intrinsic resistance [71] but also because of an intact BBB in peripheral parts of the tumour (note the positive staining for BBB-specific endothelial protein glut-1 in Figure 2B,D) that efficiently restricts the distribution of drugs to tumour cells [2]. The gene discussed is PROS1; the disease is glioblastoma.