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. The gene discussed is FN1; the disease is glioblastoma.