OBJECTIVES Mutations in the gene that encodes epidermal growth factor receptor (EGFR) are biomarkers that predict how non-small cell lung cancer (NSCLC) patients respond to EGFR-targeted therapies collectively known as tyrosine kinase inhibitors (TKIs). Thus, EGFR genotyping provides crucial information for treatment decision. Both Sanger sequencing and real-time PCR methodologies are used for EGFR genotyping. However, methods based on real-time PCR have limitations, as they may not detect rare or novel mutations. The aim of this study was to determine the prevalence of rare mutations in the tyrosine kinase domain (exons 18-21) of the EGFR gene not targeted by the most frequently used real-time PCR approaches, i.e., the cobas® EGFR Mutation Test, and the Idylla™ EGFR Mutation Assay. METHODS A total of 1228 NSCLC patients were screened for mutations in exons 18-21 of the EGFR gene using Sanger sequencing. RESULTS We observed that 252 patients (∼20%) had at least one mutation in the EGFR gene, and 38 (∼3%) carried uncommon genetic alterations that would not be identified by the cobas® or the Idylla™ tests. We further found six new single mutations and seven previously unreported compound mutations. Clinical information and patient outcome are presented for these cases. CONCLUSIONS This study highlights the value of sequencing-based approaches to identify rare mutations. Our results add to the inventory of known EGFR mutations, thus contributing to improved lung cancer precision treatment.

中文翻译：

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在NSCLC患者中检测罕见和新颖的EGFR突变：对治疗决定的意义。

目的编码表皮生长因子受体（EGFR）的基因中的突变是生物标志物，可预测非小细胞肺癌（NSCLC）患者对EGFR靶向疗法的反应，这些疗法统称为酪氨酸激酶抑制剂（TKIs）。因此，EGFR基因分型为治疗决策提供了关键信息。Sanger测序和实时PCR方法均用于EGFR基因分型。但是，基于实时PCR的方法可能无法检测到罕见或新颖的突变，因此存在局限性。这项研究的目的是确定未被最常用的实时PCR方法靶向的EGFR基因酪氨酸激酶结构域（第18-21号外显子）中的罕见突变的发生率，即cobas®EGFR突变测试，和Idylla™EGFR突变检测。方法采用Sanger测序方法，对1228例NSCLC患者的EGFR基因外显子18-21突变进行了筛选。结果我们观察到252名患者（约20％）在EGFR基因中至少有一个突变，而38名患者（约3％）进行了罕见的遗传改变，无法通过cobas®或Idylla™测试进行鉴定。我们进一步发现了六个新的单一突变和七个以前未报告的复合突变。提供了这些病例的临床信息和患者预后。结论本研究强调了基于测序的方法识别稀有突变的价值。我们的结果增加了已知EGFR突变的清单，从而有助于改善肺癌的精确治疗。结果我们观察到252名患者（约20％）的EGFR基因至少有一个突变，而38名患者（约3％）进行了罕见的遗传改变，无法通过cobas®或Idylla™测试进行鉴定。我们进一步发现了六个新的单一突变和七个以前未报告的复合突变。提供了这些病例的临床信息和患者预后。结论本研究强调了基于测序的方法识别稀有突变的价值。我们的结果增加了已知EGFR突变的清单，从而有助于改善肺癌的精确治疗。结果我们观察到252名患者（约20％）在EGFR基因中至少有一个突变，而38名患者（约3％）进行了罕见的遗传改变，无法通过cobas®或Idylla™测试进行鉴定。我们进一步发现了六个新的单一突变和七个以前未报告的复合突变。提供了这些病例的临床信息和患者预后。结论本研究强调了基于测序的方法识别稀有突变的价值。我们的结果增加了已知EGFR突变的清单，从而有助于改善肺癌的精确治疗。提供了这些病例的临床信息和患者预后。结论本研究强调了基于测序的方法识别稀有突变的价值。我们的结果增加了已知EGFR突变的清单，从而有助于改善肺癌的精确治疗。提供了这些病例的临床信息和患者预后。结论本研究强调了基于测序的方法识别稀有突变的价值。我们的结果增加了已知EGFR突变的清单，从而有助于改善肺癌的精确治疗。