EGFR and metastatic colorectal cancer: Irinotecan, a topoisomerase I inhibitor, is effective for metastatic colorectal cancer (mCRC) as a single agent [1] or in combination with fluoropyrimidines [2, 3], in the absence or presence of monoclonal antibodies raised against vascular endothelial growth factor (VEGF) or epidermal growth factor receptors (EGFR) [4–7].