PECAM1 and neoplasm: Immunohistochemistry performed on tumor tissue sections for CD31 and glucose transporter 1 (as a biomarker for 18F-FDG uptake) using antibodies revealed by HRP labelled-probes and DAB showed vasculature damage and decreased 18F-FDG uptake in tumor tissue, confirming the efficacy of the treatment as well as the suitability of the monitoring technique [66].