Nagrath Sunitha, Sequist Lecia V, Maheswaran Shyamala, Bell Daphne W, Irimia Daniel, Ulkus Lindsey, Smith Matthew R, Kwak Eunice L, Digumarthy Subba, Muzikansky Alona, Ryan Paula, Balis Ulysses J, Tompkins Ronald G, Haber Daniel A, Toner Mehmet
Surgical Services and BioMEMS Resource Center, Massachusetts General Hospital, Harvard Medical School, and Shriners Hospital for Children, Boston, Massachusetts 02114, USA.
Nature. 2007 Dec 20;450(7173):1235-9. doi: 10.1038/nature06385.
Viable tumour-derived epithelial cells (circulating tumour cells or CTCs) have been identified in peripheral blood from cancer patients and are probably the origin of intractable metastatic disease. Although extremely rare, CTCs represent a potential alternative to invasive biopsies as a source of tumour tissue for the detection, characterization and monitoring of non-haematologic cancers. The ability to identify, isolate, propagate and molecularly characterize CTC subpopulations could further the discovery of cancer stem cell biomarkers and expand the understanding of the biology of metastasis. Current strategies for isolating CTCs are limited to complex analytic approaches that generate very low yield and purity. Here we describe the development of a unique microfluidic platform (the 'CTC-chip') capable of efficient and selective separation of viable CTCs from peripheral whole blood samples, mediated by the interaction of target CTCs with antibody (EpCAM)-coated microposts under precisely controlled laminar flow conditions, and without requisite pre-labelling or processing of samples. The CTC-chip successfully identified CTCs in the peripheral blood of patients with metastatic lung, prostate, pancreatic, breast and colon cancer in 115 of 116 (99%) samples, with a range of 5-1,281 CTCs per ml and approximately 50% purity. In addition, CTCs were isolated in 7/7 patients with early-stage prostate cancer. Given the high sensitivity and specificity of the CTC-chip, we tested its potential utility in monitoring response to anti-cancer therapy. In a small cohort of patients with metastatic cancer undergoing systemic treatment, temporal changes in CTC numbers correlated reasonably well with the clinical course of disease as measured by standard radiographic methods. Thus, the CTC-chip provides a new and effective tool for accurate identification and measurement of CTCs in patients with cancer. It has broad implications in advancing both cancer biology research and clinical cancer management, including the detection, diagnosis and monitoring of cancer.
在癌症患者的外周血中已鉴定出具有活性的肿瘤来源上皮细胞（循环肿瘤细胞或CTC），它们可能是难治性转移性疾病的起源。尽管CTC极其罕见，但作为非血液系统癌症检测、特征分析和监测的肿瘤组织来源，CTC是侵入性活检的一种潜在替代方法。识别、分离、增殖和分子表征CTC亚群的能力可能会推动癌症干细胞生物标志物的发现，并加深对转移生物学的理解。目前分离CTC的策略仅限于复杂的分析方法，其产量和纯度都非常低。在此，我们描述了一种独特的微流控平台（“CTC芯片”）的开发，该平台能够在精确控制的层流条件下，通过目标CTC与抗体（EpCAM）包被的微柱相互作用，从外周全血样本中高效、选择性地分离出具有活性的CTC，且无需对样本进行预先标记或处理。CTC芯片在116份样本中的115份（99%）转移性肺癌、前列腺癌、胰腺癌、乳腺癌和结肠癌患者的外周血中成功鉴定出了CTC，每毫升样本中CTC数量在5至1281个之间，纯度约为50%。此外，在7例早期前列腺癌患者中也分离出了CTC。鉴于CTC芯片具有高灵敏度和特异性，我们测试了其在监测抗癌治疗反应方面的潜在效用。在一小群接受全身治疗的转移性癌症患者中，CTC数量的时间变化与通过标准影像学方法测量的疾病临床进程具有合理的相关性。因此，CTC芯片为准确识别和测量癌症患者的CTC提供了一种新的有效工具。它在推进癌症生物学研究和临床癌症管理（包括癌症的检测诊断和监测）方面具有广泛的意义。
