PDGFB and glioma: Immunohistochemical evaluation further validated the presence of FOXP3+ T-regulatory cells within the IL-33-expressing NF1−/+p53−/+ K1492, the N/tv-a;Cdkn2a−/−;Ptenfl/fl mice (Xfm) PDGFB-driven glioma, and primary GBM specimens albeit at fairly low but reproducible levels (Fig. 6a–d).