Patients with KRAS-mutant tumours treated with cetuximab in any combination had lower PFS compared with those with KRASWT tumours, results that extend those reported in recent clinical trials (Bokemeyer et al, 2008; Van Cutsem et al, 2009) and suggest that KRAS mutation may bypass aberrant EGFR signalling. This evidence concerns the gene KRAS and neoplasm.