title: A far-red fluorescent contrast agent to image epidermal growth factor receptor expression.
abstract: Recent developments in optical technologies have the potential to improve the speed and accuracy of screening and diagnosis of curable precancerous lesions and early cancer, thereby decreasing the costs of detection and management of epithelial malignancies. The development of molecular-specific contrast agents for markers of early neoplastic transformation could improve the detection and molecular characterization of premalignant lesions. In the oral cavity, epidermal growth factor receptor (EGFR) overexpression has been identified in early stages of premalignant lesions of the oral squamous cell carcinoma; therefore, real-time assessment of EGFR expression could serve as a biomarker for oral neoplasia. The purpose of our study was to develop a molecular-specific optical contrast agent targeted against EGFR for in vivo assessment of epithelial neoplasia using a monoclonal antibody and the far-red fluorescent dye, Alexa Fluor 660 streptavidin. In addition to demonstrating the specificity of the contrast agent for EGFR in cell lines, we document the ability to achieve penetration through 500 microm thick epithelial layers using multilayer tissue constructs and permeability-enhancing agents. Finally, using the fluorescence intensity of the contrast agent on fresh oral cavity tissue sections, we were able to distinguish abnormal from normal oral tissue. This contrast agent should have important clinical applications for use in conjunction with fluorescence spectroscopy or imaging (or both) to facilitate tumor detection and demarcation.
authors.affiliation: Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Hsu
authors.forename: Eric V
authors.initials: EV
authors.lastname: Anslyn
authors.forename: Su
authors.initials: S
authors.lastname: Dharmawardhane
authors.forename: Reza
authors.initials: R
authors.lastname: Alizadeh-Naderi
authors.forename: Jesse S
authors.initials: JS
authors.lastname: Aaron
authors.forename: Konstantin V
authors.initials: KV
authors.lastname: Sokolov
authors.forename: Adel K
authors.initials: AK
authors.lastname: El-Naggar
authors.forename: Ann M
authors.initials: AM
authors.lastname: Gillenwater
authors.forename: Rebecca R
authors.initials: RR
authors.lastname: Richards-Kortum
mesh_terms: D001706:Biopsy; D045744:Cell Line, Tumor; D066246:ErbB Receptors / Q000032:analysis / Q000378:metabolism*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique / Q000379:methods*; D005456:Fluorescent Dyes / Q000378:metabolism; D005470:Fluorometry; D006801:Humans; D018613:Microscopy, Confocal; D009061:Mouth Mucosa / Q000378:metabolism / Q000473:pathology; D009062:Mouth Neoplasms / Q000378:metabolism / Q000473:pathology; D011230:Precancerous Conditions / Q000378:metabolism / Q000473:pathology; D013194:Staining and Labeling; D019809:Streptavidin / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D019809:Streptavidin; D066246:ErbB Receptors