University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205, USA.
University of Chicago, Chicago, Illinois, 60637, USA.
Cytometry A. 2021 May;99(5):496-502. doi: 10.1002/cyto.a.24221. Epub 2020 Sep 18.
Collection of a blood sample defined by the term "blood liquid biopsy" is commonly used to detect diagnostic, prognostic, and therapeutic decision-making markers of metastatic tumors including circulating tumor cells (CTCs). Many tumors also release CTCs and other markers into lymph fluid, but the utility of lymphatic markers largely remains unexplored. Here, we introduce lymph liquid biopsy through collection of peripheral (afferent) and central (thoracic duct [TD]) lymph samples and demonstrates its feasibility for detection of stem-like CTCs potentially responsible for metastasis development and tumor relapse. Stemness of lymphatic CTCs (L-CTCs) was determined by spheroid-forming assay in vitro. Simultaneously, we tested blood CTCs by conventional blood liquid biopsy, and monitored the primary tumor size, early metastasis in a sentinel lymph node (SLN) and distant metastasis in lungs. Using a mouse model at early melanoma stage with no distant metastasis, we identified stem-like L-CTCs in lymph samples from afferent lymphatic vessels. Since these vessels transport cells from the primary tumor to SLN, our finding emphasizes the significance of the lymphatic pathway in development of SLN metastasis. Surprisingly, in pre-metastatic disease, stem-like L-CTCs were detected in lymph samples from the TD, which directly empties lymph into blood circulation. This suggests a new contribution of the lymphatic system to initiation of distant metastasis. Integration of lymph and blood liquid biopsies demonstrated that all mice with early melanoma had stem-like CTCs in at least one of three samples (afferent lymph, TD lymph, and blood). At the stage of distant metastasis, spheroid-forming L-CTCs were detected in TD lymph, but not in afferent lymph. Altogether, our results demonstrated that lymph liquid biopsy and testing L-CTCs holds promise for diagnosis and prognosis of early metastasis. © 2020 International Society for Advancement of Cytometry.
术语“血液液体活检”所定义的血液样本采集通常用于检测包括循环肿瘤细胞（CTC）在内的转移性肿瘤的诊断、预后和治疗决策标志物。许多肿瘤也会将 CTC 和其他标志物释放到淋巴液中，但淋巴标志物的实用性在很大程度上仍未得到探索。在这里，我们通过采集外周（输入）和中央（胸导管[TD]）淋巴样本引入了淋巴液体活检，并证明其用于检测潜在负责转移发展和肿瘤复发的干细胞样 CTC 的可行性。淋巴 CTC（L-CTC）的干性通过体外球体形成测定来确定。同时，我们通过常规血液液体活检测试了血液 CTC，并监测了原发肿瘤的大小、前哨淋巴结（SLN）中的早期转移和肺部的远处转移。在早期黑色素瘤阶段尚无远处转移的小鼠模型中，我们在输入淋巴管的淋巴样本中鉴定出了具有干细胞样特征的 L-CTC。由于这些血管将细胞从原发性肿瘤输送到 SLN，我们的发现强调了淋巴途径在 SLN 转移发展中的重要性。令人惊讶的是，在预转移疾病中，在直接将淋巴排入血液循环的 TD 的淋巴样本中检测到了具有干细胞样特征的 L-CTC。这表明淋巴系统对远处转移的启动有新的贡献。淋巴和血液液体活检的整合表明，所有患有早期黑色素瘤的小鼠在至少一个三个样本（输入淋巴管、TD 淋巴管和血液）中都具有干细胞样 CTC。在远处转移阶段，在 TD 淋巴中检测到形成球体的 L-CTC，但在输入淋巴中未检测到。总之，我们的研究结果表明，淋巴液体活检和 L-CTC 检测有望用于早期转移的诊断和预后。 © 2020 国际细胞分析学会。
