Non‐small cell lung cancer harboring a rare EGFR L747P mutation showing intrinsic resistance to both gefitinib and osimertinib (AZD9291): A case report

The most common EGFR mutations in non‐small cell lung cancer are exon 19 deletions and exon 21 point mutations, which are both sensitive to EGFR‐tyrosine kinase inhibitors. However, rare EGFR mutations do exist and how these mutations respond to tyrosine kinase inhibitors is not well understood. A Chinese woman diagnosed with stage IV lung adenocarcinoma harbored a rare EGFR L747P (2239‐2240 TT > CC) mutation, and treatment with gefitinib and osimertinib failed to achieve the desired effect. Herein, possible correlations between gene analysis and the outcomes of subsequent treatment are discussed.