EGFR and metastatic colorectal cancer: For the treatment of unresectable metastatic colorectal cancer, systemic chemotherapeutic agents such as fluoropyrimidines, irinotecan (CPT-11), oxaliplatin, and targeted agents such as bevacizumab (an anti-VEGF monoclonal antibody) and cetuximab, or panitumumab (anti-EGFR monoclonal antibodies) are currently used, while the survival of patients with unresectable metastatic colorectal cancer has improved (2–5).