Evidence-based guidelines recommend cytotoxic chemotherapy (e.g. oxaliplatin, irinotecan or fluoropyrimidines) as first- and second-line treatment in patients with metastatic CRC (mCRC), with the addition of anti-epidermal growth factor receptor (EGFR) agents (i.e. cetuximab or panitumumab) in those with wild-type RAS tumours or the anti-vascular endothelial growth factor (VEGF) agent bevacizumab2. The gene discussed is EGFR; the disease is neoplasm.