PDPN deletion in glioma cells causes reduction of intratumoral platelet aggregates. (A) Immunofluorescence staining of CD41 (green) and CD31 (red) of DKO-NSC and TKO^{Pdpn neg}-NSC orthotopic tumors. Cellular nuclei are stained with DAPI and pseudocolored in blue. Scale bars, 100 µm. Arrows indicate vessels with CD41⁺ platelets inside the lumen (left); arrowheads indicate CD41⁺ platelet aggregates within tumor microenvironment (right). (B) Quantification of the tumor area covered by CD41staining. Mean ± standard deviation shown. n = 3; statistical analysis: Student t test. (C) Representative images of DKO-NSC and TKO^{Pdpn neg}-NSC orthotopic tumors stained for CD31 (red). Scale bars, 200 µm. (D) Quantification of tumor area covered by CD31⁺ vessels. Mean ± standard deviation shown. n = 3; statistical analysis: Student t test. (E) In vitro platelet activation measured as CD41-CD62P⁺⁺ platelets incubated with tumor cells isolated from either DKO-NSC or TKO^{Pdpn neg}-NSC orthotopic gliomas. Mean ± standard deviation shown. n = 3; statistical analysis: Student t test. (F) Kaplan-Meier survival curve of mice transplanted with either DKO-NSC or TKO^{Pdpn neg}-NSC cells. Statistical analysis: Mantel-Cox test, P = .542. *P < .05; **P < .01. N.S., not significant.