Biomolecular imaging of colorectal tumor lesions using a FITC-labeled scFv-Cκ fragment antibody

For the sensitive diagnosis of colorectal cancer lesions, advanced molecular imaging techniques using cancer-specific targets have emerged. However, issues regarding the clearance of unbound probes and immunogenicity remain unresolved. To overcome these limitations, we developed a small-sized scFv antibody fragment conjugated with FITC for the real-time detection of colorectal cancer by in vivo molecular endoscopy imaging. A small-sized scFv fragment can target colon cancer secreted protein-2 (CCSP-2), highly expressed in colorectal adenocarcinoma tissues; moreover, its full-length IgG probe has been used for molecular imaging previously. To assess the efficacy of anti-CCSP-2 scFv-FITC, surgical specimens were obtained from 21 patients with colorectal cancer for ex vivo molecular fluorescence analysis, histology, and immunohistochemistry. Orthotopic mice were administered with anti-CCSP-2 scFv-FITC topically and intravenously, and distinct tumor lesions were observed by real-time fluorescence colonoscopy. The fluorescence imaging of human colon cancer specimens allowed the differentiation of malignant tissues from non-malignant tissues ( p