Circulating Tumor Cells in Early and Advanced Breast Cancer; Biology and Prognostic Value

Liquid biopsy in lung cancer: The role of circulating tumor cells in diagnosis, treatment, and prognosis

Despite numerous therapeutic advancements, such as immune checkpoint inhibitors, lung cancer continues to be the leading cause of cancer-related mortality. Therefore, the identification of cancer at an early stage is becoming a significant subject in contemporary oncology. Despite significant advancements in early detection tactics in recent decades, they continue to provide challenges because of the inconspicuous symptoms observed during the early stages of the primary tumor. Presently, tumor biomarkers and imaging techniques are extensively employed across different forms of cancer. Nevertheless, every approach has its own set of constraints. In certain instances, the detriments outweigh the advantages. Hence, there is an urgent need to enhance early detection methods. Currently, liquid biopsy is considered more flexible and not intrusive method in comparison to conventional test for early detection. Circulating tumor cells (CTCs) are crucial components of liquid biopsy and have a pivotal function in the spread and formation of secondary tumors. These indicators show great promise in the early identification of cancer. This study presents a comprehensive examination of the methodologies employed for the isolation and enrichment of circulating tumor cells (CTCs) in lung cancer. Additionally, it explores the formation of clusters of CTCs, which have a pivotal function in facilitating the effective dissemination of cancer to distant organs. In addition, we discuss the importance of CTCs in the detection, treatment, and prognosis of lung cancer.

Characterization of EpCAM-Positive and EpCAM-Negative Tumor Cells in Early-Stage Breast Cancer

Most studies on CTCs have focused on isolating cells that express EpCAM. In this study, we emphasize the presence of EpCAM-negative and EpCAMlow CTCs, in addition to EpCAMhigh CTCs, in early BC. We evaluated stem cell markers (CD44/CD24 and CD133) and EMT markers (N-cadherin) in each subpopulation. Our findings indicate that all stemness variants were present in both EpCAMhigh and EpCAM-negative CTCs, whereas only one variant of stemness (nonCD44+CD24-/CD133+) was observed among EpCAMlow CTCs. Nearly all EpCAMhigh CTCs were represented by CD133+ stem cells. Notably, the hybrid EMT phenotype was more prevalent among EpCAM-negative CTCs. scRNA-seq of isolated CTCs and primary tumor partially confirmed this pattern. Therefore, further investigation is imperative to elucidate the prognostic significance of EpCAM-negative and EpCAMlow CTCs.

Copy number alterations: a catastrophic orchestration of the breast cancer genome

Breast cancer (BCa) is a prevalent malignancy that predominantly affects women around the world. Somatic copy number alterations (CNAs) are tumor-specific amplifications or deletions of DNA segments that often drive BCa development and therapy resistance. Hence, the complex patterns of CNAs complement BCa classification systems. In addition, understanding the precise contributions of CNAs is essential for tailoring personalized treatment approaches. This review highlights how tumor evolution drives the acquisition of CNAs, which in turn shape the genomic landscapes of BCas. It also discusses advanced methodologies for identifying recurrent CNAs, studying CNAs in BCa and their clinical impact.

Circulating Tumor Cells: Pathological, Molecular and Functional Characteristics

This Special Issue, 'Circulating Tumor Cells: Pathological, Molecular and Functional Characteristics 1 [...].

Circulating tumor cells clusters and their role in Breast cancer metastasis; a review of literature

Breast cancer is a significant and deadly threat to women globally. Moreover, Breast cancer metastasis is a complicated process involving multiple biological stages, which is considered a substantial cause of death, where cancer cells spread from the original tumor to other organs in the body-representing the primary mortality factor. Circulating tumor cells (CTCs) are cancer cells detached from the primary or metastatic tumor and enter the bloodstream, allowing them to establish new metastatic sites. CTCs can travel alone or in groups called CTC clusters. Studies have shown that CTC clusters have more potential for metastasis and a poorer prognosis than individual CTCs in breast cancer patients. However, our understanding of CTC clusters' formation, structure, function, and detection is still limited. This review summarizes the current knowledge of CTC clusters' biological properties, isolation, and prognostic significance in breast cancer. It also highlights the challenges and future directions for research and clinical application of CTC clusters.

Molecular perspectives on systemic priming and concomitant immunity in colorectal carcinoma

The progression of metastasis, a complex systemic disease, is facilitated by interactions between tumor cells and their isolated microenvironments. Over the past few decades, researchers have investigated the metastatic spread of cancer extensively, identifying multiple stages in the process, such as intravasation, extravasation, tumor latency, and the development of micrometastasis and macrometastasis. The premetastatic niche is established in target organs by the accumulation of aberrant immune cells and extracellular matrix proteins. The "seed and soil" idea, which has become widely known and accepted, is being used to this day to guide cancer studies. Changes in the local and systemic immune systems have a major impact on whether an infection spreads or not. The belief that the immune response may play a role in slowing tumor growth and may be beneficial against the metastatic disease underpins the responsiveness shown in the immunological landscape of metastasis. Various hypotheses on the phylogenesis of metastases have been proposed in the past. The primary tumor's secreting factors shape the intratumoral microenvironment and the immune landscape, allowing this progress to be made. Therefore, it is evident that among disseminated tumor cells, there are distinct phenotypes that either carry budding for metastasis or have the ability to obtain this potential or in systemic priming through contact with substantial metastatic niches that have implications for medicinal chemistry. Concurrent immunity signals that the main tumor induces an immune response that may not be strong enough to eradicate the tumor. Immunotherapy's success with some cancer patients shows that it is possible to effectively destroy even advanced-stage tumors by modifying the microenvironment and tumor-immune cell interactions. This review focuses on the metastasome in colorectal carcinoma and the therapeutic implications of site-specific metastasis, systemic priming, tumor spread, and the relationship between the immune system and metastasis.

3D sponge loaded with cisplatin-CS-calcium alginate MPs utilized as a void-filling prosthesis for the efficient postoperative prevention of tumor recurrence and metastasis

Intraoperative bleeding is a pivotal factor in the initiation of early recurrence and tumor metastasis following breast cancer excision. Distinct advantages are conferred upon postoperative breast cancer treatment through the utilization of locally administered implant therapies. This study devised a novel 3D sponge implant containing cisplatin-loaded chitosan-calcium alginate MPs capable of exerting combined chemotherapy and hemostasis effects. This innovative local drug-delivery implant absorbed blood and residual tumor cells post-tumor resection. Furthermore, the cisplatin-loaded chitosan-calcium alginate MPs sustainably targeted and eliminated cancer cells, thereby diminishing the risk of local recurrence and distant metastasis. This hydrogel material can also contribute to breast reconstruction, indicating the potential application of the 3D sponge in drug delivery for breast cancer treatment.

Circulating Tumor Cells as Predictive and Prognostic Biomarkers in Solid Tumors

Circulating tumor cells (CTCs) have emerged as pivotal biomarkers with significant predictive and prognostic implications in solid tumors. Their presence in peripheral blood offers a non-invasive window into the dynamic landscape of cancer progression and treatment response. This narrative literature review synthesizes the current state of knowledge surrounding the multifaceted role of CTCs in predicting clinical outcomes and informing prognosis across a spectrum of solid tumor malignancies. This review delves into the evolving landscape of CTC-based research, emphasizing their potential as early indicators of disease recurrence, metastatic potential, and therapeutic resistance. Moreover, we have underscored the dynamic nature of CTCs and their implications for personalized medicine. A descriptive and critical analysis of CTC detection methodologies, their clinical relevance, and their associated challenges is also presented, with a focus on recent advancements and emerging technologies. Furthermore, we examine the integration of CTC-based liquid biopsies into clinical practice, highlighting their role in guiding treatment decisions, monitoring treatment efficacy, and facilitating precision oncology. This review highlights the transformative impact of CTCs as predictive and prognostic biomarkers in the management of solid tumors by promoting a deeper understanding of the clinical relevance of CTCs and their role in advancing the field of oncology.

Predictive significance of HIF-1α, Snail, and PD-L1 expression in breast cancer

Currently, the prediction of breast cancer (BC) effectiveness to drug treatment is based on determining the expression level of steroid hormone receptors and human epidermal growth factor receptor type 2 (HER2). However, significant differences in individual response to drug treatment require the search for new predictive markers. Here, by comprehensively examining HIF-1α, Snail, and PD-L1 expression in BC tumor tissue, we demonstrate that high levels of these markers correlate with unfavorable factors of BC prognosis: the presence of regional and distant metastases and lymphovascular and perineural invasion. Analyzing the predictive significance of markers, we show that the most significant predictors of chemoresistant HER2-negative BC are a high PD-L1 level and a low Snail level, while in HER2-positive BC, only a high PD-L1 level is an independent predictor of chemoresistant BC. Our results suggest that using immune checkpoint inhibitors in these groups of patients may improve drug therapy effectiveness.

Predicting Patterns of Distant Metastasis in Breast Cancer Patients following Local Regional Therapy Using Machine Learning

Up to 30% of breast cancer (BC) patients will develop distant metastases (DM), for which there is no cure. Here, statistical and machine learning (ML) models were developed to estimate the risk of site-specific DM following local-regional therapy. This retrospective study cohort included 175 patients diagnosed with invasive BC who later developed DM. Clinicopathological information was collected for analysis. Outcome variables were the first site of metastasis (brain, bone or visceral) and the time interval (months) to developing DM. Multivariate statistical analysis and ML-based multivariable gradient boosting machines identified factors associated with these outcomes. Machine learning models predicted the site of DM, demonstrating an area under the curve of 0.74, 0.75, and 0.73 for brain, bone and visceral sites, respectively. Overall, most patients (57%) developed bone metastases, with increased odds associated with estrogen receptor (ER) positivity. Human epidermal growth factor receptor-2 (HER2) positivity and non-anthracycline chemotherapy regimens were associated with a decreased risk of bone DM, while brain metastasis was associated with ER-negativity. Furthermore, non-anthracycline chemotherapy alone was a significant predictor of visceral metastasis. Here, clinicopathologic and treatment variables used in ML prediction models predict the first site of metastasis in BC. Further validation may guide focused patient-specific surveillance practices.

The Expression of Trace Amine-Associated Receptors (TAARs) in Breast Cancer Is Coincident with the Expression of Neuroactive Ligand-Receptor Systems and Depends on Tumor Intrinsic Subtype

Currently, the contribution of trace amine-associated receptors (TAARs) to breast cancer (BC) is recognized, but their associations with various pathological characteristics are not yet understood. There is accumulated transcriptomic data for BC tumors, which are represented in publicly accessible databases. We estimated TAARs' (including TAAR1, TAAR2, TAAR5, TAAR6, TAAR8, and TAAR9) associations with BC stage, grade, and molecular subtypes in these data and identified that the expression of all TAARs was associated with more unfavorable cancer subtypes, including basal-like and HER2-positive tumors. Also, the significant upregulation of all TAARs was demonstrated in circulating tumor cells compared to the metastatic lesions. Considering that co-expressed genes are more likely to be involved in the same biologic processes, we analyzed genes that are co-expressed with TAARs in BC. These gene sets were enriched with the genes of the olfactory transduction pathway and neuroactive ligand-receptor interaction participants. TAARs are co-expressed with G-protein-coupled receptors of monoamine neurotransmitters including dopamine, norepinephrine, and serotonin as well as with other neuroactive ligand-specific receptors. Since TAAR1 is able to modulate the activity of monoamine receptors that are involved in the regulation of BC growth, TAAR1 and potentially other TAARs may be regarded as prospective therapeutic targets for breast cancer.

Correlation analysis of circulating tumor cells and Claudin-4 in breast cancer

Objective: We aimed to explore the relationship between peripheral blood circulating tumor cells (CTCs) and the expression of Claudin-4 in patients with breast cancer, and further explore the potential impact on clinical prognosis and risk assessment. Methods: We classified and enumerated circulating tumor cells in the blood of breast cancer patients by CTC-enriched in situ hybridization and the detection of Claudin-4 expression by immunohistochemistry. We carried out an analysis of the correlation between the two and the comparison of their impact on clinical parameters and prognosis. Results: There were 38 patients with a low expression of Claudin-4 and 27 patients with a high expression of Claudin-4. Compared with Claudin-4 low-expression patients, the number of CTCs was higher in patients with high Claudin-4 expression (11.7 vs. 7.4, p < 0.001). High Claudin-4 expression was associated with a lower count of epithelial CTCs (E-CTCs) (3.4 vs. 5.0, p = 0.033), higher counts of mesenchymal CTCs (M-CTC) (4.4 vs. 1.1, p < 0.001), and epithelial/mesenchymal CTCs (E/M-CTCs) (4.0 vs. 3.5, p = 0.021). The intensity of Claudin-4 was positively correlated with CTC (r_s = 0.43, p = 0.001). Multivariate COX regression analysis showed that CTC counts (HR = 1.3, p < 0.001), Claudin-4 (HR = 4.6, p = 0.008), and Lymphatic metastasis (HR = 12.9, p = 0.001) were independent factors for poor prognosis. COX regression of CTC classification showed that epithelial/mesenchymal CTCs (E/M-CTC) (HR = 1.9, p = 0.001) and mesenchymal CTCs (M-CTC) (HR = 1.5, p = 0.001) were independent influencing factors of adverse reactions in breast cancer patients. Conclusion: The number of CTC in breast cancer is positively correlated with the expression of Claudin-4. High CTC counts and a high proportion of M-CTCs correlated with Claudin-4 expression. CTC counts and Claudin-4 expression were independent predictors of poor prognosis in breast cancer patients.

Association of Circulating Tumor Cells, Megakaryocytes and a High Immune-Inflammatory Environment in Metastatic Breast Cancer

Liquid biopsy is becoming an important source of new biomarkers during the treatment of metastatic cancer patients. Using size-based microfluid technology, we isolated circulating tumor cells (CTCs) from metastatic breast cancer patients to evaluate their presence and cluster formation, as well as the presence of megakaryocytes and immune-inflammatory blood cells, and to correlate their presence with clinicopathological data and overall survival (OS). In total, 59 patients (median age 60.4 years) were included in the study: 62.7% luminal A/B-like, 20.3% HER2-positive, and 17% triple-negative. Our results showed that at least one CTC was present in 79.7% and ≥5 CTCs in 35.2% of the patients. CTC clusters were present in patients with ≥5 CTCs only (in 19.2% of them), and megakaryocytes were present in 52% of all patients. The presence of CTC clusters and megakaryocytes was positively associated with the CTC count. Patients with low pan-inflammatory value (PIV), low systemic immune-inflammatory index (SII), and low relative change from baseline (ΔPIV%, ΔSII%) were associated with significantly higher OS than their counterparts. ΔPIV%, the presence of infection in the last month, and a long duration of metastatic disease were identified as independent prognostic factors for OS. The interplay of CTCs, CTC clusters, megakaryocytes, and PIV needs to be further explored.

A novel microfluidic system for enrichment of functional circulating tumor cells in cancer patient blood samples by combining cell size and invasiveness

A highly invasive subpopulation of circulating tumor cells (CTCs) may constitute seeds for metastases, which are therefore considered functional CTCs. However, there are few effective strategies to detect CTCs based on invasive phenotypes. Herein, we focused on functional CTCs with high invasiveness and designed an integrated microfluidic system to differentiate the invasive potential of CTCs for more accurate metastasis prediction. By combining size-based enrichment and invasiveness-based analysis, the system managed to continuously remove most hemocytes by 8 μm gaps and analyze the invasiveness of the enriched CTCs by Matrigel loading. In addition to a device, a single pump and a Petri dish were included to provide an FBS gradient for driving cell invasion and maintain a long-term cell culture. The system successfully identified functional CTCs derived from different types of cancer patients, including colorectal, kidney and bladder cancer patients, using whole blood without any sample pretreatment process. Within 28 cases of colorectal cancer patients, functional CTCs were detected in 61.54% of patients with metastases, along with stronger invasiveness evaluated by migration/invasion distance than those from patients without metastases (P < 0.05). Furthermore, one bladder cancer patient was diagnosed with recurrence six months after detection, indicating the excellent value for cancer metastases prediction. In addition, great phenotypic heterogeneity of CTCs was also observed at the single-cell level, including invasion, proliferation and dormancy, which provided an effective strategy for metastasis prediction based on CTC function as a single cell.

Utilization of Circulating Tumor Cells in the Management of Solid Tumors

Circulating tumor cells (CTCs) are tumor cells shed from the primary tumor into circulation, with clusters of CTCs responsible for cancer metastases. CTC detection and isolation from the bloodstream are based on properties distinguishing CTCs from normal blood cells. Current CTC detection techniques can be divided into two main categories: label dependent, which depends upon antibodies that selectively bind cell surface antigens present on CTCs, or label-independent detection, which is detection based on the size, deformability, and biophysical properties of CTCs. CTCs may play significant roles in cancer screening, diagnosis, treatment navigation, including prognostication and precision medicine, and surveillance. In cancer screening, capturing and evaluating CTCs from peripheral blood could be a strategy to detect cancer at its earliest stage. Cancer diagnosis using liquid biopsy could also have tremendous benefits. Full utilization of CTCs in the clinical management of malignancies may be feasible in the near future; however, several challenges still exist. CTC assays currently lack adequate sensitivity, especially in early-stage solid malignancies, due to low numbers of detectable CTCs. As assays improve and more trials evaluate the clinical utility of CTC detection in guiding therapies, we anticipate increased use in cancer management.

Liquid Biopsy in the Management of Breast Cancer Patients: Where Are We Now and Where Are We Going

Liquid biopsy (LB) is an emerging diagnostic tool that analyzes biomarkers in the blood (and possibly in other body fluids) to provide information about tumor genetics and response to therapy. This review article provides an overview of LB applications in human cancer with a focus on breast cancer patients. LB methods include circulating tumor cells and cell-free tumor products, such as circulating tumor DNA. LB has shown potential in detecting cancer at an early stage, monitoring tumor progression and recurrence, and predicting patient response to therapy. Several studies have demonstrated its clinical utility in breast cancer patients. However, there are limitations to LB, including the lack of standardized assays and the need for further validation. Future potential applications of LB include identifying the minimal residual disease, early detection of recurrence, and monitoring treatment response in various cancer types. LB represents a promising non-invasive diagnostic tool with potential applications in breast cancer diagnosis, treatment, and management. Further research is necessary to fully understand its clinical utility and overcome its current limitations.

Advances in early detection methods for solid tumors

During the last decade, non-invasive methods such as liquid biopsy have slowly replaced traditional imaging and invasive pathological methods used to diagnose and monitor cancer. Improvements in the available detection methods have enabled the early screening and diagnosis of solid tumors. In addition, advances in early detection methods have made the continuous monitoring of tumor progression using repeat sampling possible. Previously, the focus of liquid biopsy techniques included the following: 1) the isolation of circulating tumor cells, circulating tumor DNA, and extracellular tumor vesicles from solid tumor cells in the patient's blood; in addition to 2) analyzing genomic and proteomic data contained within the isolates. Recently, there has been a rapid devolvement in the techniques used to isolate and analyze molecular markers. This rapid evolvement in detection techniques improves their accuracy, especially when few samples are available. In addition, there is a tremendous expansion in the acquisition of samples and targets for testing; solid tumors can be detected from blood and other body fluids. Test objects have also expanded from samples taken directly from cancer to include indirect objects affected in cancer development. Liquid biopsy technology has limitations. Even so, this detection technique is the key to a new phase of oncogenetics. This review aims to provide an overview of the current advances in liquid biopsy marker selection, isolation, and detection methods for solid tumors. The advantages and disadvantages of liquid biopsy technology will also be explored.

Multi-omics analysis reveals a molecular landscape of the early recurrence and early metastasis in pan-cancer

Cancer remains a formidable challenge in medicine due to its propensity for recurrence and metastasis, which can result in unfavorable treatment outcomes. This challenge is particularly acute for early-stage patients, who may experience recurrence and metastasis without timely detection. Here, we first analyzed the differences in clinical characteristics among the primary tumor, recurrent tumor, and metastatic tumor in different stages of cancer, which may be caused by the molecular level. Moreover, the importance of predicting early cancer recurrence and metastasis is emphasized by survival analyses. Next, we used a multi-omics approach to identify key molecular changes associated with early cancer recurrence and metastasis and discovered that early metastasis in cancer demonstrated a high degree of genomic and cellular heterogeneity. We performed statistical comparisons for each level of omics data including gene expression, mutation, copy number variation, immune cell infiltration, and cell status. Then, various analytical techniques, such as proportional hazard model and Fisher's exact test, were used to identify specific genes or immune characteristics associated with early cancer recurrence and metastasis. For example, we observed that the overexpression of BPIFB1 and high initial B-cell infiltration levels are linked to early cancer recurrence, while the overexpression or amplification of ANKRD22 and LIPM, mutation of IGHA1 and MUC16, high fibroblast infiltration level, M1 polarization of macrophages, cellular status of DNA repair are all linked to early cancer metastasis. These findings have led us to construct classifiers, and the average area under the curve (AUC) of these classifiers was greater than 0.75 in The Cancer Genome Atlas (TCGA) cancer patients, confirming that the features we identified could be biomarkers for predicting recurrence and metastasis of early cancer. Finally, we identified specific early sensitive targets for targeted therapy and immune checkpoint inhibitor therapy. Once the biomarkers we identified changed, treatment-sensitive targets can be treated accordingly. Our study has comprehensively characterized the multi-omics characteristics and identified a panel of biomarkers of early cancer recurrence and metastasis. Overall, it provides a valuable resource for cancer recurrence and metastasis research and improves our understanding of the underlying mechanisms driving early cancer recurrence and metastasis.

Increased Circulating Epithelial Tumor Cells (CETC/CTC) over the Course of Adjuvant Radiotherapy Is a Predictor of Less Favorable Outcome in Patients with Early-Stage Breast Cancer

BACKGROUND

Adjuvant radiotherapy (RT) is an integral component of a multidisciplinary treatment strategy for early-stage breast cancer. It significantly reduces the incidence of loco-regional recurrence but also of distant events. Distant events are due to tumor cells disseminated from the primary tumor into lymphatic fluid or blood, circulating epithelial tumor cells (CETC/CTC), which can reach distant tissues and regrow into metastases. The purpose of this study is to determine changes in the number of CETC/CTC in the course of adjuvant RT, and to evaluate whether they are correlated to local recurrence and distant metastases in breast cancer patients.

METHODS

Blood from 165 patients irradiated between 2002 and 2012 was analyzed 0-6 weeks prior to and 0-6 weeks after RT using the maintrac® method, and patients were followed over a median period of 8.97 (1.16-19.09) years.

RESULTS

Patients with an increase in CETC/CTC numbers over the course of adjuvant RT had a significantly worse disease-free survival (p = 0.004) than patients with stable or decreasing CETC/CTC numbers. CETC/CTC behavior was the most important factor in predicting subsequent relapse-free survival. In particular, patients who had received neoadjuvant chemotherapy were disproportionately more likely to develop metastases when cell counts increased over the course of RT (p = 0.003; hazard ratio 4.886).

CONCLUSIONS

Using the maintrac® method, CETC/CTC were detected in almost all breast cancer patients after surgery. The increase in CETC/CTC numbers over the course of RT represents a potential predictive biomarker to judge relative risk/benefit in patients with early breast cancer. The results of this study highlight the need for prospective clinical trials on CETC/CTC status as a predictive criterion and for individualization of treatment.

CLINICAL TRIAL REGISTRATION

The trial is registered (2 May 2019) at trials.gov under NCT03935802.

A nomogram for predicting the HER2 status of circulating tumor cells and survival analysis in HER2-negative breast cancer

Background

In breast cancer patients with HER2-negative tumors (tHER2-), HER2-positive CTCs (cHER2+) were associated with promising efficacy of HER2-targeted therapy, but controversy has persisted over its prognostic effect. We developed a model including clinicopathologic parameters/blood test variables to predict cHER2 status and evaluated the prognostic value of cHER2+ in tHER2- patients.

Methods

cHER2+ was detected, blood test results and clinicopathological characteristics were combined, and a nomogram was constructed to predict cHER2 status in tHER2- patients according to logistic regression analysis. The nomogram was evaluated by C-index values and calibration curve. Kaplan-Meier curves, log-rank tests, and Cox regression analyses were performed to evaluate the prognostic value of cHER2 status.

Results

TNM stage, white blood cells (WBCs), neutrophils (NEUs), uric acid (UA), De Ritis ratio [aspartate transaminase (AST)/alanine transaminase (ALT)], and high-density lipoprotein (HDL) were found to be associated with cHER2 status in tHER2- patients in univariate logistic regression analysis, in which UA and De Ritis ratio remained significant in multivariate logistic regression analysis. A model combining these six variables was constructed, the C-index was 0.745 (95% CI: 0.630-0.860), and the calibration curve presented a perfect predictive consistency. In survival analysis, patients of the subgroups "with cHER2+/UA-low" (p = 0.015) and "with cHER2+/De Ritis ratio - high" (p = 0.006) had a significantly decreased disease-free survival (DFS).

Conclusions

Our nomogram, based on TNM stage, WBC, NEU, UA, De Ritis ratio, and HDL, may excellently predict the cHER2 status of tHER2- patients. Incorporation with UA and De Ritis ratio may enhance the prognostic value of cHER2 status.

Circulating tumor cell isolation for cancer diagnosis and prognosis

Circulating tumor cells (CTCs) are tumor cells that shed from the primary tumor and intravasate into the peripheral blood circulation system responsible for metastasis. Sensitive detection of CTCs from clinical samples can serve as an effective tool in cancer diagnosis and prognosis through liquid biopsy. Current CTC detection technologies mainly reply on the biomarker-mediated platforms including magnetic beads, microfluidic chips or size-sensitive microfiltration which can compromise detection sensitivity due to tumor heterogeneity. A more sensitive, biomarker independent CTCs isolation technique has been recently developed with the surface-charged superparamagnetic nanoprobe capable of different EMT subpopulation CTC capture from 1 mL clinical blood. In this review, this new strategy is compared with the conventional techniques on biomarker specificity, impact of protein corona, effect of glycolysis on cell surface charge, and accurate CTC identification. Correlations between CTC enumeration and molecular profiling in clinical blood and cancer prognosis are provided for clinical cancer management.

Clinical Utility of Circulating Tumor Cells in Patients With Esophageal Cancer

Background

As one of the most aggressive gastrointestinal tract cancers, esophageal carcinoma (EC) had the tenth morbidity and sixth mortality rate globally in 2020. This study was conducted to investigate whether circulating tumor cells (CTCs) could be used as diagnostic and prognostic tools for patients with EC.

Methods

Peripheral blood samples were collected from 129 patients newly diagnosed with EC, 17 individuals with benign diseases, and 75 healthy donors for CTC analysis using the negative enrichment-fluorescence in situ hybridization (NE-FISH) approach. The relationship between CTCs (counts and karyotypes) and clinicopathological features was then investigated. Moreover, overall survival (OS) and progression-free survival (PFS) were analyzed to evaluate the predictive value of CTCs.

Results

The detection of CTCs using the NE-FISH approach helped in differentiating patients with EC from benign or healthy controls at a threshold of 2 per 3.2 ml peripheral blood with a sensitivity and specificity of 70.54% and 96.74%, respectively (area under the curve = 0.826, 95% CI 0.770–0.874, p < 0.001). The CTC count was associated with tumor depth (p = 0.012), but there was no correlation with other clinicopathological characteristics. Furthermore, the proportion of CTCs with chromosome 7 triploidy was linked to distant metastasis (p = 0.033) and TNM stage (p = 0.002). The OS was significantly shorter for patients with CTCs ≥ 3 than for those with CTCs < 3. Univariate analysis revealed that sex, vascular invasion, distant metastasis, tumor depth, lymph node metastasis, and TNM stage were the significant prognostic factors for patients with EC. Multivariate analysis demonstrated that distant metastasis (hazard ratio (HR) 3.262, 95% CI 1.671–6.369, p = 0.001 for PFS; HR 3.759, 95% CI 1.867–7.571, p < 0.001 for OS) was a significant prognostic factor for patients with EC.

Conclusions

Detection of CTCs using NE-FISH could be helpful in the diagnosis of EC. The proportion of CTCs with chromosome 7 triploidy was related to distant metastasis and TNM stage. Patients with CTCs ≥ 3 had short OS, while distant metastasis was an independent factor indicating a poor prognosis for patients with EC.

The Role of Circulating Tumor Cells in the Prognosis of Metastatic Triple-Negative Breast Cancers: A Systematic Review of the Literature

Breast cancer is one of the leading causes of death in women worldwide. One subtype of breast cancer is the triple-negative, which accounts for 15% of total breast cancer cases and is known for its poor prognosis. The main cause of death is due to metastasis. Circulating tumor cells (CTCs) play a key role in the metastatic process. CTCs arise either by detaching from the primary tumor or from cancer stem cells undergoing an epithelial-to-mesenchymal transition (EMT). This review aims to present up-to-date data concerning the role of CTC numbers in relation to the prognostic and treatment response in metastatic triple-negative breast cancer (mTNBC) patients, and also to discuss the methods used for CTCs’ identification. A search in the MEDLINE database was performed. A total of 234 articles were identified. The results of the 24 eligible studies showed that positive CTC status is associated with shorter overall survival (OS) and progression-free survival (PFS) in mTNBC patients. Furthermore, a decrease in number of CTCs during therapy seems to be a favorable prognostic factor, making CTCs’ detection an important prognostic tool before and during therapy in mTNBC patients. The methods used for CTC detection are still developing and need further improvement.

Gene signatures of circulating breast cancer cell models are a source of novel molecular determinants of metastasis and improve circulating tumor cell detection in patients

Background

Progression to stage IV disease remains the main cause of breast cancer-related deaths. Increasing knowledge on the hematogenous phase of metastasis is key for exploiting the entire window of opportunity to interfere with early dissemination and to achieve a more effective disease control. Recent evidence suggests that circulating tumor cells (CTCs) possess diverse adaptive mechanisms to survive in blood and eventually metastasize, encouraging research into CTC-directed therapies.

Methods

On the hypothesis that the distinguishing molecular features of CTCs reveal useful information on metastasis biology and disease outcome, we compared the transcriptome of CTCs, primary tumors, lymph-node and lung metastases of the MDA-MB-231 xenograft model, and assessed the biological role of a panel of selected genes, by in vitro and in vivo functional assays, and their clinical significance in M0 and M+ breast cancer patients.

Results

We found that hematogenous dissemination is governed by a transcriptional program and identified a CTC signature that includes 192 up-regulated genes, mainly related to cell plasticity and adaptation, and 282 down-regulated genes, involved in chromatin remodeling and transcription. Among genes up-regulated in CTCs, FADS3 was found to increases cell membrane fluidity and promote hematogenous diffusion and lung metastasis formation. TFF3 was observed to be associated with a subset of CTCs with epithelial-like features in the experimental model and in a cohort of 44 breast cancer patients, and to play a role in cell migration, invasion and blood-borne dissemination. The analysis of clinical samples with a panel of CTC-specific genes (ADPRHL1, ELF3, FCF1, TFF1 and TFF3) considerably improved CTC detection as compared with epithelial and tumor-associated markers both in M0 and stage IV patients, and CTC kinetics informed disease relapse in the neoadjuvant setting.

Conclusions

Our findings provide evidence on the potential of a CTC-specific molecular profile as source of metastasis-relevant genes in breast cancer experimental models and in patients. Thanks to transcriptome analysis we generated a novel CTC signature in the MDA-MB-231 xenograft model, adding a new piece to the current knowledge on the key players that orchestrate tumor cell hematogenous dissemination and breast cancer metastasis, and expanding the list of CTC-related biomarkers for future validation studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02259-8.

Emerging roles of epithelial-mesenchymal plasticity in invasion-metastasis cascade and therapy resistance

Strong association of cancer incidence and its progression with mortality highlights the need to decipher the cellular and molecular mechanisms that drive tumor cells to rapidly progress to metastatic disease and therapy resistance. Epithelial-mesenchymal plasticity (EMP) emerged as a key regulator of metastatic outgrowth. It allows neoplastic epithelial cells to delaminate from their neighbors either individually or collectively, traverse the extracellular matrix (ECM) barrier, enter into the circulation, and establish distal metastases. Plasticity between epithelial and mesenchymal states and the existence of hybrid epithelial/mesenchymal (E/M) phenotypes are increasingly being reported in different tumor contexts. Small subset of cancer cells with stemness called cancer stem cells (CSCs) exhibit plasticity, possess high tumorigenic potential, and contribute to high degree of tumoral heterogeneity. EMP characterized by the presence of dynamic intermediate states is reported to be influenced by (epi)genomic reprograming, growth factor signaling, inflammation, and low oxygen generated by tumor stromal microenvironment. EMP alters the genotypic and phenotypic characteristics of tumor cells/CSCs, disrupts tissue homeostasis, induces the reprogramming of angiogenic and immune recognition functions, and renders tumor cells to survive hostile microenvironments and resist therapy. The present review summarizes the roles of EMP in tumor invasion and metastasis and provides an update on therapeutic strategies to target the metastatic and refractory cancers.

Technical Challenges for CTC Implementation in Breast Cancer

Breast cancer is the most common neoplasm in women worldwide. Tissue biopsy, currently the gold standard to obtain tumor molecular information, is invasive and might be affected by tumor heterogeneity rendering it incapable to portray the complete dynamic picture by the absence of specific genetic changes during the evolution of the disease. In contrast, liquid biopsy can provide unique opportunities for real-time monitoring of disease progression, treatment response and for studying tumor heterogeneity combining the information of DNA that tumors spread in the blood (circulating tumor DNA) with CTCs analysis. In this review, we analyze the technical and biological challenges for isolation and characterization of circulating tumor cells from breast cancer patients. Circulating tumor cell (CTC) enumeration value is included in numerous clinical studies due to the prognostic's role of these cells. Despite this, there are so many questions pending to answer. How to manage lymphocytes background, how to distinguish the CTCs subtypes or how to work with frozen samples, are some of the issues that will discuss in this review. Based on our experience, we try to address these issues and other technical limitations that should be solved to optimize the standardization of protocols, sample extraction procedures, circulating-tumor material isolation (CTCs vs. ctDNA) and the very diverse methodologies employed, aiming to consolidate the use of CTCs in the clinic. Furthermore, we think that new approaches focusing on isolation CTCs in other body fluids such as cerebrospinal or ascitic fluid are necessary to increase the opportunities of circulating tumor cells in the practice clinic as well as to study the promising role of CTC clusters and their prognostic value in metastatic breast cancer.

Prospective Monitoring of Circulating Epithelial Tumor Cells (CETC) Reveals Changes in Gene Expression during Adjuvant Radiotherapy of Breast Cancer Patients

Circulating epithelial tumor cells (CETC) are considered to be responsible for the formation of metastases. Therefore, their importance as prognostic and/or predictive markers in breast cancer is being intensively investigated. Here, the reliability of single cell expression analyses in isolated and collected CETC from whole blood samples of patients with early-stage breast cancer before and after radiotherapy (RT) using the maintrac^® method was investigated. Single-cell expression analyses were performed with qRT-PCR on a panel of selected genes: GAPDH, EpCAM, NANOG, Bcl-2, TLR 4, COX-2, PIK3CA, Her-2/neu, Vimentin, c-Met, Ki-67. In all patients, viable CETC were detected prior to and at the end of radiotherapy. In 7 of the 9 (77.8%) subjects examined, the CETC number at the end of the radiotherapy series was higher than before. The majority of genes analyzed showed increased expression after completion of radiotherapy compared to baseline. Procedures and methods used in this pilot study proved to be feasible. The method is suitable for further investigation of the underlying molecular biological mechanisms occurring in cells surviving radiotherapy and possibly the development of radiation resistance.

Dissecting Breast Cancer Circulating Tumor Cells Competence via Modelling Metastasis in Zebrafish

BACKGROUND

Cancer metastasis is a deathly process, and a better understanding of the different steps is needed. The shedding of circulating tumor cells (CTCs) and CTC-cluster from the primary tumor, its survival in circulation, and homing are key events of the metastasis cascade. In vitro models of CTCs and in vivo models of metastasis represent an excellent opportunity to delve into the behavior of metastatic cells, to gain understanding on how secondary tumors appear.

METHODS

Using the zebrafish embryo, in combination with the mouse and in vitro assays, as an in vivo model of the spatiotemporal development of metastases, we study the metastatic competency of breast cancer CTCs and CTC-clusters and the molecular mechanisms.

RESULTS

CTC-clusters disseminated at a lower frequency than single CTCs in the zebrafish and showed a reduced capacity to invade. A temporal follow-up of the behavior of disseminated CTCs showed a higher survival and proliferation capacity of CTC-clusters, supported by their increased resistance to fluid shear stress. These data were corroborated in mouse studies. In addition, a differential gene signature was observed, with CTC-clusters upregulating cell cycle and stemness related genes.

CONCLUSIONS

The zebrafish embryo is a valuable model system to understand the biology of breast cancer CTCs and CTC-clusters.

3D Multicellular Stem-Like Human Breast Tumor Spheroids Enhance Tumorigenicity of Orthotopic Xenografts in Athymic Nude Rat Model

Simple Summary

Breast cancer presents a unique clinical problem because of the variety of cellular subtypes present, including cancer stem cells (CSCs). Breast CSCs can induce the formation of new blood vessels at the site of tumor growth and a develop metastatic phenotype by enhancing a stromal cell response, similar to that of the primary breast cancer. The aim of this study was to investigate breast cancer cells cultured in stromal stem cell factor-supplemented media to generate 3D spheroids that exhibit increased stem-like properties. These 3D stem-like spheroids reproducibly and efficiently established orthotopic breast cancer xenografts in the athymic nude rat. This approach enables a means to develop orthotopic tumors with a stem-like phenotype in a larger athymic rat rodent model of human breast cancer.

Abstract

Therapeutic targeting of stem cells needs to be strategically developed to control tumor growth and prevent metastatic burden successfully. Breast cancer presents a unique clinical problem because of the variety of cellular subtypes present, including cancer stem cells (CSCs). The development of 3D stem-like properties of human breast tumor spheroids in stem cell factor conditioned media was investigated in orthotopic xenografts for enhanced tumorgenicity in the athymic nude rat model. MCF-7, ZR-75-1, and MDA-MB-231 breast cancer cell lines were cultured in serum-free, stem cell factor-supplemented medium under non-adherent conditions and passaged to generate 3rd generation spheroids. The spheroids were co-cultured with fetal lung fibroblast (FLF) cells before orthotopic heterotransplantation into the mammary fat pads of athymic nude rats. Excised xenografts were assessed histologically by H&E staining and immunohistochemistry for breast cancer marker (ERB1), proliferation marker (Ki67), mitotic marker (pHH3), hypoxia marker (HIF-2α), CSC markers (CD47, CD44, CD24, and CD133), and vascularization markers (CD31, CD34). Breast cancer cells cultured in stem cell factor supplemented medium generated 3D spheroids exhibited increased stem-like characteristics. The 3D stem-like spheroids co-cultured with FLF as supporting stroma reproducibly and efficiently established orthotopic breast cancer xenografts in the athymic nude rat.

The molecular profiling of solid tumors by liquid biopsy: a position paper of the AIOM-SIAPEC-IAP-SIBioC-SIC-SIF Italian Scientific Societies

The term liquid biopsy (LB) refers to the use of various biological fluids as a surrogate for neoplastic tissue to achieve information for diagnostic, prognostic and predictive purposes. In the current clinical practice, LB is used for the identification of driver mutations in circulating tumor DNA derived from both tumor tissue and circulating neoplastic cells. As suggested by a growing body of evidence, however, there are several clinical settings where biological samples other than tissue could be used in the routine practice to identify potentially predictive biomarkers of either response or resistance to targeted treatments. New applications are emerging as useful clinical tools, and other blood derivatives, such as circulating tumor cells, circulating tumor RNA, microRNAs, platelets, extracellular vesicles, as well as other biofluids such as urine and cerebrospinal fluid, may be adopted in the near future. Despite the evident advantages compared with tissue biopsy, LB still presents some limitations due to both biological and technological issues. In this context, the absence of harmonized procedures corresponds to an unmet clinical need, ultimately affecting the rapid implementation of LB in clinical practice. In this position paper, based on experts’ opinions, the AIOM–SIAPEC-IAP–SIBIOC–SIF Italian Scientific Societies critically discuss the most relevant technical issues of LB, the current and emerging evidences, with the aim to optimizing the applications of LB in the clinical setting.

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In the current clinical practice LB is used for the identification of driver mutations in circulating tumor DNA (ctDNA).

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New applications in tumors other than non-small-cell lung cancer (NSCLC) are emerging as useful clinical tools.

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Other blood derivatives, together with other biofluids, are an active field of research and may be adopted in the near future.

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Despite the evident advantages, liquid biopsy still presents limitations due to both biological and technological issues.

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Standardization of the procedures needs to be addressed to ensure widespread implementation in clinical practice.

Evaluation of circulating tumor cells as a prognostic biomarker for early recurrence in stage II-III breast cancer patients using CytoSorter® system: a retrospective study

PURPOSE

Circulating tumor cells (CTCs) are known to be associated with late recurrence and poor prognosis in breast cancer (BC). Different CTC enrichment platforms have different CTC cut-off values for poor prognosis. This study aimed to evaluate whether preoperative CTCs could be a prognostic factor for early recurrence of disease in BC patients with resectable tumors, and to ascertain the CTC cut-off value for early recurrence with CytoSorter® CTC system.

METHODS

Thirty-six stage II and III BC patients who had preoperative (pre-op) CTC detection and underwent a mastectomy or lumpectomy for curative intent between January and May 2018 were enrolled in this retrospective study. CTC detection was performed using CytoSorter® CTC system. Correlations of patients' demographics, clinicopathological characteristics, adjuvant therapies and CTCs with relapse and survival were evaluated.

RESULTS

CTCs were detected in 32 out of 36 patients before surgery. Nine patients developed relapses during follow-up, and seven of them were distant recurrence. Univariate analysis showed that CTCs were correlated with two-year recurrence free survival (RFS) and distant RFS (D-RFS) (P = 0.013 and 0.029, respectively). Two-year RFS and D-RFS were 85.2% and 88.9%, respectively, for patients with <4 CTCs, while 44.4% and 55.6%, respectively, for patients with ≧4 CTCs. In multivariate analysis, only CTC was shown to be correlated with two-year RFS (HR: 0.219, 95% CI: [0.058-0.82], P = 0.024) and D-RFS (HR: 0.218, 95% CI [0.048-0.977], P = 0.047).

CONCLUSION

BC patients with pre-op CTCs ≥4 per four mL of blood have significantly reduced two-year RFS and D-RFS. A pre-op CTC cut-off of four per four mL of blood was found for CytoSorter® to identify BC patients with a higher risk for early recurrence.

The Role of Circulating Tumor Cells in Chemoresistant Metastatic Breast Cancer

Breast cancer is the most frequent form of cancer among women and is one of the leading causes of death. Two routes of the metastatic process have been described: linear and parallel progression. A key factor is represented by circulating tumor cells (CTCs). CTCs detach from the primary tumor or develop from cancer stem cells (CSCs) that undergo epithelial-to-mesenchymal transition (EMT). CTCs migrate to the distant site where the reverse process occurs and a new tumor arises. One of the key problems of metastatic disease is chemoresistance, which leads to treatment failure and, eventually, death. The aim of this review is to present up-to-date data regarding the role of CTCs in chemoresistance in metastatic breast cancer (MBC) patients. A search in Cochrane Library and MEDLINE databases was performed. A total of 125 articles were identified. The results of the final 12 eligible studies revealed that CTCs having stem cell features and those with mesenchymal features are aggressive subtypes of cells that survive chemotherapy, being responsible for chemoresistance and thus for disease progression in MBC patients. The hemodynamic shear stress, alongside dynamic changes among CTCs during the disease, is also an important disease progression factor.

Diagnostic performance of circulating cell-free DNA for hepatocellular carcinoma: a systematic review and meta-analysis

Background: We aimed to assess the diagnostic performance of circulating cell-free DNA (cfDNA) in hepatocellular carcinoma (HCC). Materials & methods: After a systematic literature search bivariate linear mixed models were used to integrate sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio. The area under receiver operating characteristics curves of the included studies was used to estimate the diagnostic value. Results: Thirty-eight articles enrolled in quantitative synthesis. In overall analysis the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio and area under receiver operating characteristics curves for cfDNA in distinguishing HCC patients from healthy controls were 0.54, 0.90, 5.23, 0.51, 10.27 and 0.82, respectively. Conclusion: This study suggests that cfDNA has a promising diagnostic accuracy in detection of HCC.

How to Predict Metastasis in Luminal Breast Cancer? Current Solutions and Future Prospects

Breast cancer metastasis is the main cause of breast cancer mortality. Luminal breast cancer represents the majority of breast cancer cases and, despite relatively good prognosis, its heterogeneity creates problems with a proper stratification of patients and correct identification of the group with a high risk of metastatic relapse. Current prognostic tools are based on the analysis of the primary tumor and, despite their undisputed power of prediction, they might be insufficient to foresee the relapse in an accurate and precise manner, especially if the relapse occurs after a long period of dormancy, which is very common in luminal breast cancer. New approaches tend to rely on body fluid analyses, which have the advantage of being non-invasive and versatile and may be repeated and used for monitoring the disease in the long run. In this review we describe the current, newly-developed, and only-just-discovered methods which are or may become useful in the assessment of the probability of the relapse.

Slug and E-Cadherin: Stealth Accomplices?

During physiological epithelial-mesenchymal transition (EMT), which is important for embryogenesis and wound healing, epithelial cells activate a program to remodel their structure and achieve a mesenchymal fate. In cancer cells, EMT confers increased invasiveness and tumor-initiating capacity, which contribute to metastasis and resistance to therapeutics. However, cellular plasticity that navigates between epithelial and mesenchymal states and maintenance of a hybrid or partial E/M phenotype appears to be even more important for cancer progression. Besides other core EMT transcription factors, the well-characterized Snail-family proteins Snail (SNAI1) and Slug (SNAI2) play important roles in both physiological and pathological EMT. Often mentioned in unison, they do, however, differ in their functions in many scenarios. Indeed, Slug expression does not always correlate with complete EMT or loss of E-cadherin (CDH1). For example, Slug plays important roles in mammary epithelial cell progenitor cell lineage commitment and differentiation, DNA damage responses, hematopoietic stem cell self-renewal, and in pathologies such as pulmonary fibrosis and atherosclerosis. In this Perspective, we highlight Slug functions in mammary epithelial cells and breast cancer as a “non-EMT factor” in basal epithelial cells and stem cells with focus reports that demonstrate co-expression of Slug and E-cadherin. We speculate that Slug and E-cadherin may cooperate in normal mammary gland and breast cancer/stem cells and advocate for functional assessment of such Slug⁺/E-cadherin^low/+ (SNAI2⁺/CDH1^low/+) “basal-like epithelial” cells. Thus, Slug may be regarded as less of an EMT factor than driver of the basal epithelial cell phenotype.