Cooperation between PDPN and TF in tumor microthrombosis in glioma xenografts. (A) Martius scarlet blue trichrome (MSB) staining for thrombi in 4 representative xenografts expressing PDPN alone (U373PT), PDPN and TF (U373TF-G11-PT), or TF alone (U373vIII) (left panels); bars represent 100 μm. Quantification of occluded vessels containing fibrin thrombi (right panel) indicates significant elevation in the case of U373TF-G11-PT (PDPN+/TF⁺) tumors. (B) Immunofluorescent staining of tumors for endothelial cells (CD31, red) and fibrin (green) (left panels). Fibrin-occluded vessels predominated in U373TF-G11-PT tumors (PDPN⁺/TF⁺) (right panel); magnification ×400. (C) Immunohistochemical staining of glioma xenografts for mouse platelet marker CD61 (left panels). Platelet-rich thrombi were most abundant in U373TF-G11-PT (PDPN and TF–double expressing) tumors (right panel); bars represent 100 μm. **P ≤ .01, ***P ≤ .001, ****P ≤ .0001, ANOVA multiple-comparison analysis. ns, nonsignificant