Real‐time detection of epidermal growth factor receptor expression in fresh oral cavity biopsies using a molecular‐specific contrast agent

Abstract

Early diagnosis of individuals with high risk of developing head and neck squamous carcinoma should lead to decreased morbidity and increased survival. To aid in noninvasive early detection of oral neoplasia in vivo, we have developed a molecular-specific fluorescent contrast agent, consisting of a far-red fluorescent dye coupled to a monoclonal antibody targeted against the epidermal growth factor receptor. In our study, we used organ cultures of normal and neoplastic human oral tissue to evaluate the capabilities of using this contrast agent to enhance clinical diagnosis. Fresh tissue sections were prepared from 34 biopsies of clinically normal and abnormal oral mucosa from 17 consenting patients. Samples were exposed to contrast agent, rinsed and the presence of bound agent was detected using fluorescence confocal microscopy. Simple assays to assess cytotoxicity of the dye used in the agent and to determine labeling efficacy at physiologic temperatures were also performed. Results indicate that the mean fluorescence intensity (MFI) of samples with dysplasia and cancer are higher than that of the normal sample from the same patient, and that this increase in fluorescence could potentially be used in the early detection and delineation of premalignant lesions. Normal tissue could be distinguished from cancer or moderate dysplasia, using either the ratio of the MFI of abnormal to normal tissue or the MFI obtained from the epithelial surface. No detrimental effects from the dye were observed over a 4-day period. These results indicate that the use of this optical contrast agent could yield important clinical advantages for noninvasive early detection and molecular characterization of oral mucosa. ' 2006 Wiley-Liss, Inc.Key words: fluorescent contrast agent; epidermal growth factor receptor; molecular-specific contrast agentThe 5-year survival rate for oral cancer has not improved significantly in the last 3 decades, despite numerous advances in treatment modalities.

Molecular imaging of glucose uptake in oral neoplasia following topical application of fluorescently labeled deoxy‐glucose

“…Negative controls included unlabeled tissue phantoms as well as cell-free collagen phantoms which were prepared and labeled in the same way as phantoms containing cells. After widefield imaging, tissue phantoms were sliced transversely using a Krumdieck tissue slicer to obtain viable 200-300 micron thick specimens 29. Transverse slices were imaged using a confocal fluorescence microscope using the same settings as for suspension cultures.…”

Confocal laser endomicroscopy in head and neck cancer

“…The successful use of mAbs targeted against the epidermal growth factor receptor (EGFR) or vascular endothelial growth factor (VEGF) has been reported in organ cultures, tissue samples and human tumours grown in mice [31][32][33]. This might help to target high-risk lesions during endoscopy and to predict response to targeted treatment [33].…”

Optical contrast agents and imaging systems for detection and diagnosis of cancer

“…1). Hsu et al targeted the epidermal growth factor receptor (EGFR), a transmembrane protein found to be overexpressed in many epithelial cancers, by conjugation of an Alexa fluor 660 organic dye to a monoclonal antibody against EGFR [11]. On labeling fresh tissue biopsies from oral cancer patients with the antibody-dye conjugate, confocal microscopy indicated significantly increased fluorescence intensity within the epithelium in samples with dysplasia and cancer compared to paired normal sites, particularly in the most superficial region.…”