The present invention relates to specific binding members, particularly antibodies and fragments thereof, which bind to amplified epidermal growth factor receptor (EGFR) and to the de2-7 EGFR truncation of the EGFR. In particular, the epitope recognized by the specific binding members, particularly antibodies and fragments thereof, is enhanced or evident upon aberrant post-translational modification. These specific binding members are useful in the diagnosis and treatment of cancer. The binding members of the present invention may also be used in therapy in combination with chemotherapeutics or anti-cancer agents and/or with other antibodies or fragments thereof,