H&E staining of human xenotransplants (M21) in mice. H&E staining of the tTF-NGR–treated tumors showed thrombosis of blood vessels and extensive blood pooling due to vascular disruption (arrows indicating the occluded blood vessels; A,B). The tumors in the saline (C,D) or the tTF (E,F)–treated control group exhibited no thrombosis. Red stripes in panel E are artifacts (arrow). Original magnifications, ×200 (A,C,E) and ×400 (B,D,F).