PDGFRB and glioblastoma: The final cell type common to all three specimens was characterised by expression of PDGFRB (PDGFRβ/CD140b), MCAM (CD146), THY1 (CD90), FN (fibronectin) and type IV collagen genes (Figure 5b), markers typical of mature pericytes, including those in normal human brain and glioblastoma.39, 40, 41