Kong Say Li, Liu Xingliang, Suhaimi Nur-Afidah Mohamed, Koh Kenneth Jia Hao, Hu Min, Lee Daniel Yoke San, Cima Igor, Phyo Wai Min, Lee Esther Xing Wei, Tai Joyce A, Foong Yu Miin, Vo Jess Honganh, Koh Poh Koon, Zhang Tong, Ying Jackie Y, Lim Bing, Tan Min-Han, Hillmer Axel M
Genome Institute of Singapore, Singapore 138672, Singapore.
Institute of Bioengineering and Nanotechnology, Singapore 138669, Singapore.
Oncotarget. 2017 Jul 10;8(40):68026-68037. doi: 10.18632/oncotarget.19138. eCollection 2017 Sep 15.
Studies on circulating tumor cells (CTCs) have largely focused on platform development and CTC enumeration rather than on the genomic characterization of CTCs. To address this, we performed targeted sequencing of CTCs of colorectal cancer patients and compared the mutations with the matched primary tumors. We collected preoperative blood and matched primary tumor samples from 48 colorectal cancer patients. CTCs were isolated using a label-free microfiltration device on a silicon microsieve. Upon whole genome amplification, we performed amplicon-based targeted sequencing on a panel of 39 druggable and frequently mutated genes on both CTCs and fresh-frozen tumor samples. We developed an analysis pipeline to minimize false-positive detection of somatic mutations in amplified DNA. In 60% of the CTC-enriched blood samples, we detected primary tumor matching mutations. We found a significant positive correlation between the allele frequencies of somatic mutations detected in CTCs and abnormal CEA serum level. Strikingly, we found driver mutations and amplifications in cancer and druggable genes such as , and . In addition, we found that CTCs carried mutation signatures that resembled the signatures of their primary tumors. Cumulatively, our study defined genetic signatures and somatic mutation frequency of colorectal CTCs. The identification of druggable mutations in CTCs of preoperative colorectal cancer patients could lead to more timely and focused therapeutic interventions.
对循环肿瘤细胞（CTCs）的研究主要集中在平台开发和CTCs计数上，而非CTCs的基因组特征。为解决这一问题，我们对结直肠癌患者的CTCs进行了靶向测序，并将突变与匹配的原发肿瘤进行比较。我们收集了48例结直肠癌患者的术前血液和匹配的原发肿瘤样本。使用硅微筛上的无标记微滤装置分离CTCs。全基因组扩增后，我们对CTCs和新鲜冷冻肿瘤样本中一组39个可药物化且频繁突变的基因进行了基于扩增子的靶向测序。我们开发了一种分析流程，以尽量减少扩增DNA中体细胞突变的假阳性检测。在60%的富含CTCs的血液样本中，我们检测到了原发肿瘤匹配突变。我们发现CTCs中检测到的体细胞突变等位基因频率与异常癌胚抗原血清水平之间存在显著正相关。引人注目的是，我们在癌症和可药物化基因（如 、 和 ）中发现了驱动突变和扩增。此外，我们发现CTCs携带的突变特征与其原发肿瘤的特征相似。总的来说，我们的研究确定了结直肠癌CTCs的遗传特征和体细胞突变频率。术前结直肠癌患者CTCs中可药物化突变的鉴定可能会导致更及时、更有针对性的治疗干预。
