In this context, previous studies have demonstrated improved clinical outcomes in gefitinib-treated NSCLC patients with detectable EGFR mutations in serum (Kimura et al, 2006, 2007) and plasma (Bai et al, 2009) vs patients with NSCLC harbouring wild-type EGFR. The current study examined clinical outcomes in EGFR mutation-positive patients diagnosed by tumour biopsy according to their EGFR mutation status by cfDNA. The gene discussed is EGFR; the disease is neoplasm.