PDGFB and glioma: Importantly, addition of Pax3 to PDGF-B overexpression caused a subset of tumors to progress to high-grade glioma based on the presence of microvascular proliferation (0/5 PDGF-B versus 5/20 PDGF-B + Pax3 high-grade, p = 0.056, Figure 5b-c).