TGFB1 and central nervous system cancer: Even if adding TGF-β to the pericytic compartment or co-culturing barrier-tight HBVP/PBMVEC membranes with glioma cells at the time point we measured an intact and tight barrier function (Figure 1C,D, Figure 2A–C and Supplementary Figure S1), there might be some additional TGF-β effects on PBMVECs.