Rachiglio Anna Maria, Esposito Abate Riziero, Sacco Alessandra, Pasquale Raffaella, Fenizia Francesca, Lambiase Matilde, Morabito Alessandro, Montanino Agnese, Rocco Gaetano, Romano Carmen, Nappi Anna, Iaffaioli Rosario Vincenzo, Tatangelo Fabiana, Botti Gerardo, Ciardiello Fortunato, Maiello Monica R, De Luca Antonella, Normanno Nicola
Laboratory of Pharmacogenomics, CROM-Istituto Nazionale Tumori "Fondazione G. Pascale"-IRCCS, Naples, Italy.
Thoraco-Pulmonary, Medical Oncology, Istituto Nazionale Tumori "Fondazione G. Pascale"-IRCCS, Naples, Italy.
Oncotarget. 2016 Oct 11;7(41):66595-66605. doi: 10.18632/oncotarget.10704.
The circulating free tumor DNA (ctDNA) represents an alternative, minimally invasive source of tumor DNA for molecular profiling. Targeted sequencing with next generation sequencing (NGS) can assess hundred mutations starting from a low DNA input. We performed NGS analysis of ctDNA from 44 patients with metastatic non-small-cell lung carcinoma (NSCLC) and 35 patients with metastatic colorectal carcinoma (CRC). NGS detected EGFR mutations in 17/22 plasma samples from EGFR-mutant NSCLC patients (sensitivity 77.3%). The concordance rate between tissue and plasma in NSCLC was much lower for other mutations such as KRAS that, based on the allelic frequency and the fraction of neoplastic cells, were likely to be sub-clonal. NGS also identified EGFR mutations in plasma samples from two patients with EGFR wild type tumor tissue. Both mutations were confirmed by droplet digital PCR (ddPCR) in both plasma and tissue samples. In CRC, the sensitivity of the NGS plasma analysis for RAS mutations was 100% (6/6) in patients that had not resection of the primary tumor before blood drawing, and 46.2% (6/13) in patients with primary tumor resected before enrollment. Our study showed that NGS is a suitable method for plasma testing. However, its clinical sensitivity is significantly affected by the presence of the primary tumor and by the heterogeneity of driver mutations.
循环游离肿瘤DNA（ctDNA）是一种用于分子谱分析的替代性微创肿瘤DNA来源。采用新一代测序（NGS）进行靶向测序能够从低DNA输入量开始评估数百个突变。我们对44例转移性非小细胞肺癌（NSCLC）患者和35例转移性结直肠癌（CRC）患者的ctDNA进行了NGS分析。NGS在17/22份来自EGFR突变型NSCLC患者的血浆样本中检测到EGFR突变（敏感性77.3%）。对于其他突变，如KRAS，基于等位基因频率和肿瘤细胞比例，其在NSCLC组织和血浆中的一致性率要低得多，这些突变可能是亚克隆性的。NGS还在两名EGFR野生型肿瘤组织患者的血浆样本中鉴定出EGFR突变。两种突变均在血浆和组织样本中通过液滴数字PCR（ddPCR）得到证实。在CRC中，对于未在采血前切除原发肿瘤的患者，NGS血浆分析对RAS突变的敏感性为100%（6/6），而对于在入组前已切除原发肿瘤的患者，敏感性为46.2%（6/13）。我们的研究表明，NGS是一种适用于血浆检测的方法。然而，其临床敏感性受到原发肿瘤的存在以及驱动突变异质性的显著影响。
