An intravital imaging platform (FITC-dextran/CFP/tdTomato + two-photon microscopy) tracked pericytes, vessels, and tumor cells, while FACS-sorted Pdgfrb<sup>+</sup> cells from GBM and normal brain were analyzed by LC-MS/MS proteomics.<h4>Results</h4>Cre-mediated ablation of Pdgfrb-expressing cells revealed stage-dependent effects on GBM growth: early ablation inhibited progression while late ablation promoted it. The gene discussed is PDGFRB; the disease is glioblastoma.