Large phase III randomised studies in metastatic colorectal cancer have demonstrated either response rate (Cunningham et al, 2004) or time to progression (Gibson et al, 2006; Saif and Cohenuram, 2006) advantages using monoclonal antibodies, such as cetuximab, directed specifically against the epidermal growth factor receptor (EGFR). The gene discussed is EGFR; the disease is metastatic colorectal cancer.