Lozar Taja, Gersak Klara, Cemazar Maja, Kuhar Cvetka Grasic, Jesenko Tanja
Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
Institute of Oncology Ljubljana, Ljubljana, Slovenia.
Radiol Oncol. 2019 May 8;53(2):131-147. doi: 10.2478/raon-2019-0024.
Background Tumor cells can shed from the tumor, enter the circulation and travel to distant organs, where they can seed metastases. These cells are called circulating tumor cells (CTCs). The ability of CTCs to populate distant tissues and organs has led us to believe they are the primary cause of cancer metastasis. The biological properties and interaction of CTCs with other cell types during intravasation, circulation in the bloodstream, extravasation and colonization are multifaceted and include changes of CTC phenotypes that are regulated by many signaling molecules, including cytokines and chemokines. Considering a sample is readily accessible by a simple blood draw, monitoring CTC levels in the blood has exceptional implications in oncology field. A method called the liquid biopsy allows the extraction of not only CTC, but also CTC products, such as cell free DNA (cfDNA), cell free RNA (cfRNA), microRNA (miRNA) and exosomes. Conclusions The clinical utility of CTCs and their products is increasing with advances in liquid biopsy technology. Clinical applications of liquid biopsy to detect CTCs and their products are numerous and could be used for screening of the presence of the cancer in the general population, as well as for prognostic and predictive biomarkers in cancer patients. With the development of better CTC isolation technologies and clinical testing in large prospective trials, increasing clinical utility of CTCs can be expected. The understanding of their biology and interactions with other cell types, particularly with those of the immune system and the rise of immunotherapy also hold great promise for novel therapeutic possibilities.
背景 肿瘤细胞可从肿瘤上脱落，进入循环系统并转移至远处器官，在那里形成转移灶。这些细胞被称为循环肿瘤细胞（CTC）。CTC在远处组织和器官中形成转移灶的能力使我们相信它们是癌症转移的主要原因。在肿瘤细胞进入血管、在血液中循环、穿出血管和定植过程中，CTC的生物学特性及其与其他细胞类型的相互作用是多方面的，包括由许多信号分子（包括细胞因子和趋化因子）调节的CTC表型变化。考虑到通过简单的采血就能轻松获取样本，监测血液中的CTC水平在肿瘤学领域具有特殊意义。一种称为液体活检的方法不仅可以提取CTC，还可以提取CTC产物，如游离DNA（cfDNA）、游离RNA（cfRNA）、微小RNA（miRNA）和外泌体。结论 随着液体活检技术的进步，CTC及其产物的临床应用价值不断提高。液体活检在检测CTC及其产物方面的临床应用广泛，可用于普通人群癌症筛查，也可作为癌症患者的预后和预测生物标志物。随着更好的CTC分离技术的发展以及大型前瞻性试验中的临床检测，预计CTC的临床应用价值将不断提高。对其生物学特性以及与其他细胞类型（特别是与免疫系统细胞类型）相互作用的了解，以及免疫疗法的兴起，也为新的治疗可能性带来了巨大希望。
