EGFR and lung cancer: Earlier studies (Lynch et al, 2004; Paez et al, 2004; Eberhard et al, 2005; Riely et al, 2006a) had identified a subset of lung cancer patients with rapid and durable clinical responses to EGFR TKIs and found an underlying association between activating mutations in the EGFR tyrosine kinase domain and therapy response.