Visualization of tumor vasculature using anti-CD31 immunohistochemistry. Visualization of tumor vasculature using anti-CD31 immunohistochemistry. Micrographs are representative PC-3 xenografts (day 27) following treatment with Ad.Egr-TNF.11D and doxorubicin. Microvessels were visualized in paraffin-embedded tissue sections using the avidin-biotin peroxidase technique. A, untreated control; B, doxorubicin; C, Ad.Egr-TNF.11D alone; D, Ad.Egr-TNF.11D + doxorubicin. Carlos A. Lopez et al. Mol Cancer Ther 2004;3:1167-1175 ©2004 by American Association for Cancer Research