Six of the tested patients experience disease progression, and it is important to mention that in three of them (50%), mutations were detected only in CTCs or cfDNA (at baseline) but were not detected in tissue samples (Pt#8, Pt#19, Pt#29); Pt#18 and Pt#29 have the same characteristics in terms of type, stage and size of tumor, namely adenocarcinoma/ IIIA/ T2a, while Pt#8 referred squamous cell carcinoma/IIIA/T2b.Finally, in Pt#34, which relapsed, EGFR mutations were detected in both CTC-derived DNA and primary tissue (Figure 3). This evidence concerns the gene EGFR and squamous cell carcinoma.