KRAS and metastatic colorectal cancer: Recent clinical data convincingly associates response to anti-EGFR therapies with K-Ras mutation status in patients with metastatic colorectal cancer where, logically, response is preferentially observed in K-Ras wt tumours (Lievre et al, 2006; Benvenuti et al, 2007; Khambata-Ford et al, 2007; Freeman et al, 2008; Karapetis et al, 2008; Ramos et al, 2008; Loupakis et al, 2009; Van Cutsem et al, 2009) which retain the ability to respond to EGFR blockade.