Therapeutic effect of rAAV-endostatin in RCC tumor. (A) The therapeutic model. (B) A total of 10 days following OR-SC-2 inoculation, intratumoral rAAV-endostatin (1.0×1011 v.p) or control virus injections into the established tumor were performed. The xenograft tumors with rAAV-endostatin injection took longer to reach 300 mm3 compared with the control groups: rAAV-Endostatin group, 32.63±9.75 days; rAAV-EYFP group, 21.75±10.48 days; RPMI-1640 group, 21.50±11.42 days. (C) Hematoxylin and eosin staining of the OS-RC-2 kidney tumor at magnification, ×200. Representative images from three independent experiments were presented. (D) Subsequent to harvesting the xenograft (kidney) tumors, specimens were paraffin-embedded and cut into 5-µm thick sections and processed for immunohistochemical staining of factor VIII-associated antigen. The brown areas indicate microvascular structures (magnification, ×200). Representative images from three independent experiments were shown. rAAV, recombinant adenovirus-associated vector; EYFP, enhanced yellow florescent protein.