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Abstract：
Epidermal growth factor receptor (EGFR) gene mutations play an important role in the treatment management of non-small cell lung cancer (NSCLC) patients. After a first- or second-generation EGFR tyrosine kinase inhibitor (TKI) therapy, the most common resistance mechanism involves the selection of a resistant clone carrying the exon 20 p.T790M point mutation. However, also for these patients, treated with a third-generation TKI (osimertinib) several mechanisms of acquired resistance are described. Here we report the case of a 68-year-old man with an EGFR exon 19 deletion treated with gefitinib in first line and osimertinib in second line besides on the presence of a p.T790M mutation, who developed an uncommon EGFR exon 20 p.L792Q point mutation at the progression to osimertinib, with the concomitant modification of the original sensitizing EGFR exon 19 deletion and the loss of p.T790M mutation.
摘要：
表皮生长因子受体（EGFR）基因突变在非小细胞肺癌（NSCLC）患者的治疗管理中起着重要作用。在第一代或第二代EGFR酪氨酸激酶抑制剂（TKI）治疗后，最常见的抗性机制包括选择携带外显子20p.T790M点突变的抗性克隆。然而,对于这些患者来说，用第三代TKI（奥希替尼）治疗的几种获得性耐药机制被描述。在这里，我们报告了一个68岁的EGFR外显子19缺失的男性，除了存在p.T790M突变外，一线用吉非替尼和二线用奥希替尼治疗，在进展为奥希替尼的过程中出现了不常见的EGFR外显子20p.L792Q点突变，伴随着原始致敏EGFR外显子19缺失的修饰和p.T790M突变的丢失。
