Cetuximab and panitumumab have shown efficacy both as monotherapy (Amado et al, 2008; Karapetis et al, 2008) and in combination with chemotherapy (Tol et al, 2009; Van Cutsem et al, 2009) in patients with KRAS wild-type metastatic CRC. The gene discussed is KRAS; the disease is colorectal carcinoma.