Histology of intratumor vasculatures.

(A, B) Tumor vasculatures are visualized by anti-PECAM-1 immunostaining. Micrographs are of representative sections prepared from the control (A) and AFL4-treated mice (B) (×200). (C, D) Representative H&E-stained tumor sections from controls (C) and anti-VEGFR-3–treated mice (D) (×200). In anti-VEGFR-3–treated tumors, many micro-hemorrhages are observed (arrows). (E) Vessel counts per field were determined from at least 5 different vision fields of sections from control (n = 4; 65 ± 5.2/high-power field) and AFL4-treated mice (n = 4; 27.5 ± 5.3/high-power field) (×200). Data are plotted as mean ± SEM. *P < .01. (F) The number of micro-hemorrhages was scored in high-power fields (×200) of H&E-stained tumor sections (at least 5 different vision fields each of 4 tumors). Control, 0.73 ± 0.13/high-power field; AFL4, 3.9 ± 0.46/high-power field. Data are plotted as mean ± SEM. *P < .01. Statistical differences between groups were computed using the Student t test. (G) Representative SEM of a postcapillary venule in control tumors (×3800). (H) SEM of a postcapillary venule in anti-VEGFR-3–treated tumors reveals disruption of the endothelial sheet, exposing red blood cells (arrow) (×2200).