Summary

EGFR mutations can be analyzed with circulating tumor DNA, with an overall concordance of EGFR mutation status of 89%. The low positive predictive value of 78% was likely due to false-negative tumor samples using less sensitive methodologies such as DNA sequencing or pyrosequencing, and it increased to 93% when highly sensitive methods such as the QIAGEN Therascreen RGQ PCR kit was used for both tissue/cytology samples and plasma samples.