EGFR and colorectal cancer: Colorectal cancer (CRC) is one of the leading causes of cancer deaths worldwide.1 Almost 50% of patients with CRC develop metastatic disease, with 25% possessing distant metastases at the time of diagnosis.2 Systemic treatments for metastatic CRC (mCRC) include conventional fluoropyrimidine-based chemotherapy and biological agents that target vascular angiogenesis or the epidermal growth factor receptor (EGFR).3,4 The latter group of targeted agents include the anti-EGFR monoclonal antibodies panitumumab and cetuximab.