Figure 3 BTVs exert antitumor effects in a renal cancer OS-RC-2 xenograft mouse model. (A) Representative tumor sections from treated mice were harvested after treatment and analyzed by H&E (×40 and×100), cell proliferation (Ki67 ×400), apoptosis (TUNEL ×1000), or angiogenesis (VEGF ×200), by immunohistochemistry. The H&E staining shows that the tumor tissue had disintegrated into smaller components. T – tumor tissue, S – tumor stroma. Sinusoid-like blood vessels were occlusive, degenerated, or absent entirely. The VEGF staining showed less immunoreactivity in BTV-treated tumors than in control groups. (B) Tumor volume (mm3) was measured and the data are presented as mean±SD. Body weight was monitored continuously, and the data shown represent the mean±SD. (C) Quantification of mitotic index (left), and apoptosis (right). Labeled cells were counted in an average of 6 high-power fields. Data represent means±SEM. (D) H&E staining also revealed apoptotic-type cells, such as condensed nuclei and cytoplasm (arrow), in BTV-treated tumors.