Examples of normal staining in glioblastoma vessels are shown in Figure 1, including intact PDGFRA copy number in vessels with surrounding tumor demonstrating amplification of the receptor (Figure 1a), and overexpression of EGFR or loss of PTEN protein in glioblastoma cells with vascular structures failing to show such changes (Figure 1b,c). The gene discussed is PTEN; the disease is glioblastoma.