EGFR and metastatic colorectal cancer: Regorafenib is used to treat metastatic colorectal cancer patients who have previously received fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy, anti-vascular endothelial growth factor (VEGF) therapy, and (if wild-type RAS) anti-epidermal growth factor receptor (EGFR) treatment [4–6].