The analysis of circulating tumor cells (CTCs) is an outstanding tool to provide insights into the biology of metastatic cancers, to monitor disease progression and with potential for use in liquid biopsy-based personalized cancer treatment. These goals are ambitious, yet recent studies are already allowing a sharper understanding of the strengths, challenges, and opportunities provided by liquid biopsy approaches. For instance, through single-cell-resolution genomics and transcriptomics, it is becoming increasingly clear that CTCs are heterogeneous at multiple levels and that only a fraction of them is capable of initiating metastasis. It also appears that CTCs adopt multiple ways to enhance their metastatic potential, including homotypic clustering and heterotypic interactions with immune and stromal cells. On the clinical side, both CTC enumeration and molecular analysis may provide new means to monitor cancer progression and to take individualized treatment decisions, but their use for early cancer detection appears to be challenging compared to that of other tumor derivatives such as circulating tumor DNA. In this review, we summarize current data on CTC biology and CTC-based clinical applications that are likely to impact our understanding of the metastatic process and to influence the clinical management of patients with metastatic cancer, including new prospects that may favor the implementation of precision medicine.

中文翻译：

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追踪癌症进展：从循环肿瘤细胞到转移。

循环肿瘤细胞（CTC）的分析是出色的工具，可提供有关转移性癌症生物学的见解，监测疾病的进展以及在基于液体活检的个性化癌症治疗中的潜力。这些目标是雄心勃勃的，但是最近的研究已经使人们对液体活检方法的优势，挑战和机遇有了更深刻的了解。例如，通过单细胞分辨率的基因组学和转录组学，越来越清楚的是CTC在多个水平上是异质的，并且只有其中一部分能够启动转移。似乎CTC还采用多种方法来增强其转移潜力，包括同型聚类以及与免疫细胞和基质细胞的异型相互作用。在临床方面，CTC枚举和分子分析都可能提供监测癌症进展和做出个性化治疗决策的新手段，但是与其他肿瘤衍生物（例如循环肿瘤DNA）相比，将其用于早期癌症检测似乎具有挑战性。在这篇综述中，我们总结了有关CTC生物学和基于CTC的临床应用的当前数据，这些数据可能会影响我们对转移过程的理解并影响转移性癌症患者的临床管理，包括可能有利于实施精确的新前景药物。但与其他肿瘤衍生物（例如循环肿瘤DNA）相比，将其用于早期癌症检测似乎具有挑战性。在这篇综述中，我们总结了有关CTC生物学和基于CTC的临床应用的当前数据，这些数据可能会影响我们对转移过程的理解并影响转移性癌症患者的临床管理，包括可能有利于实施精确的新前景药物。但与其他肿瘤衍生物（例如循环肿瘤DNA）相比，将其用于早期癌症检测似乎具有挑战性。在这篇综述中，我们总结了有关CTC生物学和基于CTC的临床应用的当前数据，这些数据可能会影响我们对转移过程的理解并影响转移性癌症患者的临床管理，包括可能有利于实施精确的新前景药物。