FIGURE 1.

A, Detection of EGFR alterations in the plasma of patient 1. DNA was extracted from plasma, and EGFR alterations (p.L858R▪; p.T790M □) were detected by allele-specific amplification using the Therascreen RGQ EGFR kit as previously described.⁴ The fraction of mutated copies of the EGFR gene was determined using a standard curve generated using serial dilutions of mutated DNA extracted from control slides of formalin-fixed paraffin-embedded cell lines block with defined ratios of mutant alleles (Horizon Discovery, Cambridge, United Kingdom) into wild-type DNA. Chest computed tomography images at baseline (B) and after 3 months of tyrosine kinase inhibitor treatment (C).