The patient underwent thoracoscopic right lower lobe lobectomy for lung adenocarcinoma....EGFR status was positive for the L861Q mutation in exon 21. At 31 months after surgery, the recurrence appeared as vertebral and multiple pulmonary lesions, and the treatment with osimertinib showed satisfactory response seven months after starting the treatment.

In this study, two EGFR L861Q variants cell lines (EGFR L861Q variant and EGFR L861Q + exon 19 deletion variant) were established by CRISPR-Cas9 gene-editing technology. The steady-state plasma concentrations of six TKIs (gefitinib/erlotinib/icotinib, the first generation; dacomitinib/afatinib, the second generation; and osimertinib, the third generation) were tested, respectively....EGFR L861Q + 19del variant and EGFR L861Q variant showed significant sensitivity to six first-in-class TKIs.