Targeting epidermal growth factor receptor in tumors: from conventional monoclonal antibodies via heavy chain-only antibodies to nanobodies.

The discovery of naturally occurring heavy chain only antibodies and their further development into small recombinant 'nanobodies' offers attractive applications in drug targeting. Here, we describe the properties of nanobodies that have been developed to target the epidermal growth factor receptor (EGFR) and contrast these to the characteristics of heavy chain only antibodies and conventional antibodies. EGFR is overexpressed in many tumors and is an attractive target for tumor-directed drug targeting.