EGFR and non-small cell lung carcinoma: Evidences from current largest data enrolling 229 advanced NSCLC patients with matched NGS-based ctDNA and tissue tests demonstrated that the positive predictive value (PPV) of ctDNA sequencing was 100% for EGFR exon 21 L858R mutation, 98% for EGFR exon 19 deletion, and 27% for EGFR exon 20 T790M mutation, suggesting latter acquisition of this resistance mutation [42].