Unit of Pathology, IRCCS San Raffaele Scientific Institute, Milano, Italy.
Unit of Oncology, IRCCS San Raffaele Scientific Institute, Milano, Italy.
Lung Cancer. 2019 Aug;134:225-232. doi: 10.1016/j.lungcan.2019.06.010. Epub 2019 Jun 11.
Circulating cell-free tumor DNA (ctDNA) isolated from the peripheral blood of non-small-cell lung cancer (NSCLC) patients provides biomarkers for both therapeutic target selection, particularly when direct tumor biopsy is unfeasible, and also for drug resistance monitoring. This study evaluates the reliability and feasibility of ctDNA analysis in an in-house clinical molecular diagnostic workflow.
Mutation profiling by both standard methods and Next-Generation sequencing (NGS) was carried out and compared on 2 independent lung cancer patient cohorts. Cohort 1 consisted of 50 EGFR-mutated NSCLC patients, established on tumour biopsy, for whom ctDNA was collected at disease progression after TKI-inhibitor treatment and could be used to monitor drug resistance. Cohort 2 consisted of 50 newly diagnosed lung cancer patients for whom tumour biopsy was not possible and only ctDNA was available, providing the possibility of biomarker identification.
ctDNA analysis of Cohort 1 verified the persistence of the tumour-detected EGFR activating mutation at disease progression by both standard and NGS methods, in 84% and 92% of the cases respectively. The T790M EGFR resistance mutation was identified in 71% of the ctDNA EGFR mutated samples providing vital information for their disease management. In newly diagnosed Cohort 2 patients, EGFR activating mutations were detected in 16% of the patients by both standard and NGS analysis of ctDNA in peripheral blood, providing indication to targeted-therapy otherwise unavailable for this group of patients.
The presented study investigated lung cancer ctDNA analysis, comparing conventional methods versus NGS sequencing, and demonstrated the successful use of plasma ctDNA as a template for targeted NGS tumor gene panel in an in-house routine clinical practice. More importantly, these data underline the advantages of the clinical application of ctDNA NGS analysis for identification of therapeutic targets, real-time monitoring of therapy, and resistance mechanisms in lung cancer patients.
从非小细胞肺癌（NSCLC）患者外周血中分离出的循环游离肿瘤 DNA（ctDNA）为治疗靶点的选择提供了生物标志物，尤其是在直接肿瘤活检不可行时，也为耐药监测提供了生物标志物。本研究评估了 ctDNA 分析在内部临床分子诊断工作流程中的可靠性和可行性。
对 2 个独立的肺癌患者队列同时进行了标准方法和下一代测序（NGS）的突变分析，并进行了比较。队列 1 由 50 名经肿瘤活检证实的 EGFR 突变型 NSCLC 患者组成，这些患者在接受 TKI 抑制剂治疗后疾病进展时采集了 ctDNA，可用于监测耐药情况。队列 2 由 50 名新诊断的肺癌患者组成，这些患者无法进行肿瘤活检，只有 ctDNA 可用，这为鉴定生物标志物提供了可能性。
队列 1 的 ctDNA 分析通过标准方法和 NGS 方法分别在 84%和 92%的病例中证实了肿瘤检测到的 EGFR 激活突变在疾病进展时的持续存在。在 ctDNA EGFR 突变样本中，71%的样本检测到 T790M EGFR 耐药突变，为其疾病管理提供了重要信息。在新诊断的队列 2 患者中，通过 ctDNA 外周血的标准和 NGS 分析分别在 16%的患者中检测到 EGFR 激活突变，为这组患者提供了靶向治疗的指示，否则这些患者无法获得靶向治疗。
本研究比较了传统方法与 NGS 测序在肺癌 ctDNA 分析中的应用，证明了将血浆 ctDNA 作为模板进行靶向 NGS 肿瘤基因谱分析在内部常规临床实践中的成功应用。更重要的是，这些数据强调了 ctDNA NGS 分析在识别治疗靶点、实时监测治疗和肺癌患者耐药机制方面的临床应用的优势。
