Cancer-associated thrombosis is enhanced in the pulmonary microvasculature and pulmonary tumors of endothelial HIF1α knockout mice. (A) Tumor-bearing lung cross-sections of wild-type (WT) and endothelial HIF1α knockout (EC HIF1ko) mice stained with Martius Scarlet Blue for fibrin (red) and erythrocytes (yellow). (B) Quantification of fibrin deposition and (C) microthrombi number in pulmonary microvasculature of tumor-bearing WT and EC HIF1ko mice (n = 5/group). (D) Pulmonary tumors of WT and EC HIF1ko mice stained with Martius Scarlet Blue. (E) Quantification of tumor fibrin deposition in WT and EC HIF1ko mice (n = 5/group). Images are of representative tissue cross-sections. *P < .05.