EGFR and neoplasm: In previous analyses, the detection rates for EGFR mutation in blood (plasma or serum) cfDNA compared with paired tumour tissue samples have ranged from 31% to 97% (Kimura et al, 2006, 2007; Moran et al, 2007; Bai et al, 2009; He et al, 2009; Kuang et al, 2009; Yung et al, 2009; Brevet et al, 2011; Goto et al, 2012; Liu et al, 2013; Zhao et al, 2013; Douillard et al, 2014b; Mok et al, 2015).