Nucl Med Mol Imaging.  2008 Jun;42(3):185-191.

Radiotracer Methods for Targeted Imaging of the Epidermal Growth Factor Receptor

• Jung KH
• Lee KH

Abstract

While indirect targeting strategies using reporter-genes are taking center stage in current molecular imaging research, another vital strategy has long involved direct imaging of specific receptors using radiolabeled ligands. Recently, there is renewal of immense interest in this area with particular attention to the epidermal growth factor receptor (EGFR), a transmembrane glycoprotein critically involved in the regulation of many cellular functions and malignancies. Recently, two novel classes of EGFR-targeting anticancer drugs have entered clinical trials with great expectations. These are monoclonal antibodies such as cetuximab that target the extracellular domain, and small molecule tyrosine kinase inhibitors such as gefitinib (Iressa) and erlotinib (Tarceva) that target the catalytic domain of the receptor. However, early results have showed disappointing survival benefits, disclosing a major challenge for this therapeutic strategy; namely, the need to identify tumors that are most likely to respond to the agents. To address this important clinical issue, several noninvasive imaging techniques are under investigation including radiolabeled probes based on small molecule tyrosine kinase inhibitors, anti-EGFR antibodies, and EGF peptides. This review describes the current status, limitations, and future prospects in the development of radiotracer methods for EGFR imaging.

Keyword

epidermal growth factor receptor; molecular imaging; cancer

MeSH Terms

Antibodies
Antibodies, Monoclonal
Antibodies, Monoclonal, Humanized
Catalytic Domain
Epidermal Growth Factor
Glycoproteins
Ligands
Molecular Imaging
Peptides
Protein-Tyrosine Kinases
Quinazolines
Receptor, Epidermal Growth Factor
Cetuximab
Erlotinib Hydrochloride
Antibodies
Antibodies, Monoclonal
Antibodies, Monoclonal, Humanized
Epidermal Growth Factor
Glycoproteins
Ligands
Peptides
Protein-Tyrosine Kinases
Quinazolines
Receptor, Epidermal Growth Factor