Strategies for molecular imaging of epidermal growth factor receptor tyrosine kinase in cancer.

A wealth of research has focused on developing targeted cancer therapies by specifically inhibiting epidermal growth factor receptor tyrosine kinase (EGFR-TK). However, the outcome of most EGFR-TK-targeted drugs that were approved by the Food and Drug Administration or entered clinical trials has been only moderate. Enhancement of EGFR-targeted therapy hinges on a reliable in vivo quantitative molecular imaging method. Such a method would enable monitoring of receptor drug binding and receptor occupancy in vivo; determination of the duration of EGFR inhibition in vivo; and, potentially, identification of a primary or secondary mutation in EGFR leading to drug interaction or loss of EGFR recognition by the drug. This review analyzes the most recent strategies to visualize and quantify EGFR-TK in cancer by nuclear medicine imaging and describes future directions.