The Presence of Circulating Tumor Cell Cluster Characterizes an Aggressive Hepatocellular Carcinoma Subtype

Exploring Circulating Tumor Cells: Detection Methods and Biomarkers for Clinical Evaluation in Hepatocellular Carcinoma

Circulating tumor cells (CTCs), originating from primary neoplastic tissues, infiltrate blood vessels, migrate through the bloodstream, and establish secondary tumor foci. The detection of CTCs holds significant promise for early-stage identification, diagnostic precision, therapeutic monitoring, and prognostic evaluation. It offers a non-invasive approach and has broad clinical relevance in cancer management. This comprehensive review primarily focused on CTCs as biomarkers in the diagnostic, therapeutic, and prognostic surveillance of hepatocellular carcinoma, compared their correlation with key clinical parameters and the identification of gene characteristics. It also highlighted current methodologies in CTC detection. Despite approval by the U.S. Food and Drug Administration for select malignancies, the comprehensive integration of CTCs into routine clinical practice requires procedural standardization and a deeper understanding of the underlying molecular intricacies. The challenges in CTC detection, including limited quantity, technical impediments, and cellular heterogeneity, call for concerted and further investigational efforts to advance precision in cancer diagnostics and prognostication, thus realizing the objectives of precise and personalized medicine.

A Preliminary Analysis of Circulating Tumor Microemboli from Breast Cancer Patients during Follow-Up Visits

BACKGROUND

Most breast cancer-related deaths are caused by distant metastases and drug resistance. It is important to find appropriate biomarkers to monitor the disease and to predict patient responses after treatment early and accurately. Many studies have found that clustered circulating tumor cells, with more correlations with metastatic cancer and poor survival of patients than individual ones, are promising biomarkers.

METHODS

Eighty samples from eleven patients with breast cancer during follow-up visits were examined. By using a microfluidic chip and imaging system, the number of circulating tumor cells and microemboli (CTC/CTM) were counted to assess the distribution in stratified patients and the potential in predicting the disease condition of patients after treatments during follow-up visits. Specific components and subtypes of CTM were also preliminarily investigated.

RESULTS

Compared to CTC, CTM displayed a distinguishable distribution in stratified patients, having a better AUC value, in predicting the disease progression of breast cancer patients during follow-up visits in this study. Four subtypes were categorized from the identified CTM by considering different components. In combination with CEA and CA153, enumerated CTC and CTM from individual patients were applied to monitor the disease condition and patient response to the therapy during follow-up visits.

CONCLUSIONS

The CTM and its subtypes are promising biomarkers and valuable tools for studying cancer metastasis and longitudinally monitoring cancer patients during follow-up visits.

Research progress on the multi-omics and survival status of circulating tumor cells

In the dynamic process of metastasis, circulating tumor cells (CTCs) emanate from the primary solid tumor and subsequently acquire the capacity to disengage from the basement membrane, facilitating their infiltration into the vascular system via the interstitial tissue. Given the pivotal role of CTCs in the intricate hematogenous metastasis, they have emerged as an essential resource for a deeper comprehension of cancer metastasis while also serving as a cornerstone for the development of new indicators for early cancer screening and new therapeutic targets. In the epoch of precision medicine, as CTC enrichment and separation technologies continually advance and reach full fruition, the domain of CTC research has transcended the mere straightforward detection and quantification. The rapid advancement of CTC analysis platforms has presented a compelling opportunity for in-depth exploration of CTCs within the bloodstream. Here, we provide an overview of the current status and research significance of multi-omics studies on CTCs, including genomics, transcriptomics, proteomics, and metabolomics. These studies have contributed to uncovering the unique heterogeneity of CTCs and identifying potential metastatic targets as well as specific recognition sites. We also review the impact of various states of CTCs in the bloodstream on their metastatic potential, such as clustered CTCs, interactions with other blood components, and the phenotypic states of CTCs after undergoing epithelial-mesenchymal transition (EMT). Within this context, we also discuss the therapeutic implications and potential of CTCs.

EpCAM-positive circulating tumor cells and serum AFP levels predict outcome after curative resection of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has high recurrence rates exceeding 50% despite curative resection. The serum biomarker alpha-fetoprotein (AFP) is a well-known prognostic marker for HCC. EpCAM-positive circulating tumor cells (CTC) have a high predictive value for early HCC recurrence after curatively intended resection, most likely indicating micro-metastases at the time of resection. However, sensitivity remains low. The objective of this study was to evaluate a composite test comprising both CTC and AFP to identify patients at high risk for early HCC recurrence. We prospectively enrolled 58 patients undergoing curative intended resection for HCC at a tertiary referral center. Blood specimens were obtained prior to resection and analyzed for EpCAM-positive CTC and serum AFP levels. A positive result was defined as either detection of CTC or AFP levels ≥ 400 ng/ml. Eight patients tested positive for CTC, seven for AFP, and two for both markers. A positive composite test was significantly associated with shorter early recurrence-free survival (5 vs. 16 months, p = 0.005), time to recurrence (5 vs. 16 months, p = 0.011), and overall survival (37 vs. not reached, p = 0.034). Combining CTC and AFP identified patients with poor outcome after surgical resection, for whom adjuvant or neoadjuvant therapies may be particularly desirable.

Prognostic value of preoperative circulating tumor cells for hepatocellular carcinoma with portal vein tumor thrombosis: A propensity score analysis

PURPOSE

The role of circulating tumor cells (CTCs) in hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT) is not fully understood.

METHODS

In this retrospective analysis, we included 316 HCC patients who underwent hepatectomy and preoperative CTC detection. We selected 41 pairs of matched HCC patients with and without PVTT using propensity score matching (PSM) analysis. We compared the preoperative CTC counts in patients from both the full cohort and the PSM model. We also analyzed their associations with disease-free survival (DFS) and overall survival (OS).

RESULTS

Before and after PSM analysis, the preoperative CTC counts in the HCC with PVTT group were substantially higher than in the HCC without PVTT group. In both the full cohort of patients and the PSM model, patients with CTC ≥ 2 had significantly shorter OS and DFS than patients with CTC < 2. The outcomes of HCC patients with PVTT could be well differentiated by preoperative CTC levels. HCC patients with CTC ≥ 2 had noticeably shorter OS (9.9 months vs. 24.6 months, P = 0.0003) and DFS (6.0 months vs. 12.3 months, P = 0.0041) than those with CTC < 2. Moreover, preoperative CTC ≥ 2 remained an independent predictor in all groups' multivariate analysis.

CONCLUSION

We discovered a link between preoperative CTC counts and the occurrence of PVTT and confirmed the prognostic significance of preoperative CTC in HCC patients with PVTT. These findings suggest that preoperative CTC counts have the potential to assist in identifying patients with HCC and PVTT who may benefit from surgery.

A model for the dissemination of circulating tumour cell clusters involving platelet recruitment and a plastic switch between cooperative and individual behaviours

BACKGROUND

In spite of extensive research, cancer remains a major health problem worldwide. As cancer progresses, cells acquire traits that allow them to disperse and disseminate to distant locations in the body - a process known as metastasis. While in the vasculature, these cells are referred to as circulating tumour cells (CTCs) and can manifest either as single cells or clusters of cells (i.e., CTC clusters), with the latter being the most aggressive. The increased metastatic potential of CTC clusters is generally associated with cooperative group benefits in terms of survival, including increased resistance to shear stress, anoikis, immune attacks and drugs. However, the adoption of a group phenotype poses a challenge when exiting the vasculature (extravasation) as the large size can hinder the passage through vessel walls. Despite their significant role in the metastatic process, the mechanisms through which CTC clusters extravasate remain largely unknown. Based on the observed in vivo association between CTC clusters and platelets, we hypothesized that cancer cells take advantage of the platelet-derived Transforming Growth Factor Beta 1 (TGF-β1) - a signalling factor that has been widely implicated in many aspects of cancer, to facilitate their own dissemination. To address this possibility, we evaluated the effect of exogenous TGF-β1 on an experimentally evolved non-small cell lung cancer cell line that we previously developed and used to investigate the biology of CTC clusters.

RESULTS

We found that exogenous TGF-β1 induced the dissociation of clusters in suspension into adherent single cells. Once adhered, cells released their own TGF-β1 and were able to individually migrate and invade in the absence of exogenous TGF-β1. Based on these findings we developed a model that involves a TGF-β1-mediated plastic switch between a cooperative phenotype and a single-celled stage that enables the extravasation of CTC clusters.

CONCLUSIONS

This model allows for the possibility that therapies can be developed against TGF-β1 signalling components and/or TGF-β1 target genes to suppress the metastatic potential of CTC clusters. Considering the negative impact that metastasis has on cancer prognosis and the lack of therapies against this process, interfering with the ability of CTC clusters to switch between cooperative and individual behaviours could provide new strategies to improve patient survival.

Circulating tumor cells as a prognostic biomarker in patients with hepatocellular carcinoma

Circulating tumor cells (CTCs) have been shown as a surrogate for cancer progression and prognostication. We aimed to determine an association between CTCs and survival of hepatocellular carcinoma (HCC) patients. Peripheral blood was obtained from 73 HCC patients to enumerate for epithelial CTCs/8 mL blood. CTCs were detected by immunoaffinity-based method using epithelial cell adhesion molecule (EpCAM) and mucin1 (MUC1). The CTCs detection rates of BCLC stages A, B, and C patients were 65.4% (17/26), 77.3% (17/22), and 96% (24/25), respectively, p = 0.018. Patients with CTCs < 5 cells/8 mL had significantly longer survival than those with CTCs ≥ 5 cells/8 mL (>36 vs. 4.6 months, p < 0.001). In multivariate analysis, CTP B, BCLC B, BCLC C, AFP ≥ 400 ng/mL, and CTC ≥ 5 cells/8 mL were independently associated with survival, with adjusted HRs (95%CI) of 4.1 (2.0-8.4), 3.5 (1.1-11.4), 4.7 (1.4-15.4), 2.4 (1.1-5.0), and 2.6 (1.2-8.4); p < 0.001, 0.036, 0.011, 0.025 and 0.012, respectively. The combination of CTCs ≥ 5 cells/8 mL and AFP ≥ 400 ng/mL provided additively increased HR to 5.3 (2.5-11.1), compared to HRs of 4.0 (2.0-8.0) and 3.5 (1.8-6.7) for CTCs ≥ 5 cells/8 mL and AFP ≥ 400 ng/mL, p < 0.001, respectively. The larger number of peripheral CTCs is correlated with higher tumor aggressive features and poorer survival of HCC patients. CTCs can potentially become novel prognostic biomarker in HCC.

Cell-Cell Interactions Drive Metastasis of Circulating Tumor Microemboli

Circulating tumor cells are the cellular mediators of distant metastasis in solid malignancies. Their metastatic potential can be augmented by clustering with other tumor cells or nonmalignant cells, forming circulating tumor microemboli (CTM). Cell-cell interactions are key regulators within CTM that convey enhanced metastatic properties, including improved cell survival, immune evasion, and effective extravasation into distant organs. However, the cellular and molecular mechanism of CTM formation, as well as the biology of interactions between tumor cells and immune cells, platelets, and stromal cells in the circulation, remains to be determined. Here, we review the current literature on cell-cell interactions in homotypic and heterotypic CTM and provide perspectives on therapeutic strategies to attenuate CTM-mediated metastasis by targeting cell-cell interactions.