EGFR and lung adenocarcinoma: Similarly, blood samples were collected from a 53-year-old female patient (left lung adenocarcinoma stage IVB, EGFR exon 21 L858R mutation) (Patient 1, Treat2 & Control2) and a 58-year-old female patient (left lung adenocarcinoma stage IVB, EGFR exon 19 deletion) (Patient 3, Treat4 & Control4) before and after the appearance of resistance to osimertinib.