In advanced stage NSCLC patients, ctDNA analysis obtained the first clinical approval for EGFR TKI administration in patients naïve to any treatment (basal setting) without tissue availability or with an inadequate molecular result on tissue specimens, and for the identification of EGFR exon 20 p.T790M resistance point mutation in previously treated patients (resistance setting) [12]. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.