Whilst patients with epithelial CMS2/3 tumours benefit from anti-EGFR agents given as monotherapy or combined with an oxaliplatin-based chemotherapy regimen [12–14], patients with CMS4 tumours appear to have no or even a detrimental effect when anti-EGFR is added to an oxaliplatin-based regimen [13, 14]. The gene discussed is EGFR; the disease is neoplasm.