The EGFR-A763_Y764insFQEA is a unique mutation among EGFR exon 20 insertion mutations in that it is associated with sensitivity to conventional EGFR-tyrosine kinase inhibitors. This mutation, which was not initially covered by conventional reverse transcription polymerase chain reaction (RT-PCR) genotyping method, has only been detected in clinical practice when a next-generation sequencing (NGS)-based cancer panel is implemented. We present the case of a female patient with recurrent lung adenocarcinoma from a lung tumor resected 10 years earlier. Sequential single-gene investigations and the OncomineTM Comprehensive Assay (ver.3) analysis of the recurrent tumor did not reveal any targetable driver mutations. However, the second NGS analysis with the OncoGuideTM NCC oncopanel found the EGFR-A763_Y764insFQEA mutation after tumor progression with carcinomatous lymphangiomatosis and multiple brain metastases. Osimertinib treatment improved her condition immediately. The identical EGFR-A763_Y764insFQEA mutation was detected in the tumor resected 10 years earlier. Based on this common mutation the patient was diagnosed with late recurrence of lung cancer harboring the EGFR-A763_Y764insFQEA mutation. The OncoGuideTM NCC oncopanel covered whole exons of the EGFR gene and was able to detect this mutation. In the present clinical practice, the EGFR-A763_Y764insFQEA mutation is the only treatable mutation among EGFR Ex.20 insertion mutations. We need to understand the gene mutation profile identified by each panel and consider reexamining them for this mutation.

在EGFR-A763_Y764insFQEA是当今世界上唯一的突变EGFR外显子 20 插入突变，因为它与对常规 EGFR-酪氨酸激酶抑制剂的敏感性有关。这种突变最初没有被传统的逆转录聚合酶链反应 (RT-PCR) 基因分型方法覆盖，只有在实施基于下一代测序 (NGS) 的癌症面板时才在临床实践中检测到。我们介绍了一名女性患者的病例，该患者患有 10 年前切除的肺肿瘤复发性肺腺癌。对复发性肿瘤的连续单基因研究和 OncomineTM 综合分析（第 3 版）分析未发现任何可靶向的驱动突变。然而，使用 OncoGuideTM NCC oncopanel 进行的第二次 NGS 分析发现了 EGFR-A763_Y764insFQEA 在肿瘤进展为癌性淋巴管瘤病和多发脑转移后发生突变。奥希替尼治疗立即改善了她的病情。在 10 年前切除的肿瘤中检测到相同的 EGFR-A763_Y764insFQEA 突变。基于这种常见突变，患者被诊断为晚期复发肺癌，携带 EGFR-A763_Y764insFQEA 突变。OncoGuideTM NCC oncopanel 覆盖了肿瘤的整个外显子EGFR基因并能够检测到这种突变。在目前的临床实践中，EGFR-A763_Y764insFQEA突变是EGFR Ex.20插入突变中唯一可治疗的突变。我们需要了解每个面板确定的基因突变谱，并考虑重新检查它们是否存在这种突变。