EGFR and neoplasm: EGFR mutations detected in plasma predict response to EGFR tyrosine kinase inhibitor treatment at a similar efficacy as EGFR variants detected in tumour tissue [54]; moreover, the sensitivity (66–90%) and high specificity (>95%) of EGFR mutation detection from plasma cf-DNA proves it is a viable surrogate for EGFR mutation detection in advanced NSCLC [47,48].