Detection Methods and Clinical Applications of Circulating Tumor Cells in Breast Cancer

A bibliometric analysis of global research on microbial immune microenvironment in melanoma from 2012 to 2022

BACKGROUND

Melanoma is an aggressive malignancy primarily impacting the skin, mucous membranes, and pigment epithelium. The tumor microbial microenvironment encompasses both the microorganisms inhabiting the tumor vicinity and the environmental factors influencing their interactions. Emerging evidence highlights the pivotal role of the microbial immune microenvironment in melanoma.

METHODS

We conducted an extensive review of scholarly works published from 2012 to 2022, utilizing The Web of Science Core Collection. Subsequently, we employed analytical tools such as VOSviewer, CiteSpace, and the R programming language to scrutinize prevailing research patterns within this domain.

RESULTS

A sum of 513 articles were pinpointed, with notable input coming from the United States and China. Harvard University stood out as the top-contributing institution, while the journal Science received the most citations. Current research within this sphere chiefly focuses on two principal domains: the gut microbiota and the PD-L1 pathway concerning melanoma treatment.

CONCLUSION

The study offers an extensive analysis and overview of the worldwide research landscape concerning the immune microenvironment with a focus on microbes in melanoma. It underscores the promising prospects for harnessing the microbial immune microenvironment's potential in melanoma. These findings furnish valuable insights and guidance for advancing scientific inquiry and refining clinical approaches within this dynamic field.

Circulating tumour cells predict recurrences and survival in head and neck squamous cell carcinoma patients

Patients with head and neck squamous cell carcinoma (HNSCC) are at a high risk of developing recurrence and secondary cancers. This study evaluates the prognostic and surveillance utilities of circulating tumour cells (CTCs) in HNSCC. A total of 154 HNSCC patients were recruited and followed up for 4.5 years. Blood samples were collected at baseline and follow-up. CTCs were isolated using a spiral microfluid device. Recurrence and death due to cancer were assessed during the follow-up period. In patients with HNSCC, the presence of CTCs at baseline was a predictor of recurrence (OR = 8.40, p < 0.0001) and death (OR= ∞, p < 0.0001). Patients with CTCs at baseline had poor survival outcomes (p < 0.0001). Additionally, our study found that patients with CTCs in a follow-up appointment were 2.5 times more likely to experience recurrence or death from HNSCC (p < 0.05) prior to their next clinical visit. Our study highlights the prognostic and monitoring utilities of CTCs' in HNSCC patients. Early identification of CTCs facilitates precise risk assessment, guiding treatment choices and ultimately enhancing patient outcomes.

Synthesis and antiproliferative evaluation of novel 3,5,8-trisubstituted coumarins against breast cancer

Aim: This study focused on designing and synthesizing novel derivatives of 3,5,8-trisubstituted coumarin. Results: The synthesized compounds, particularly compound 5, exhibited significant cytotoxic effects on MCF-7 cells, surpassing staurosporine, and reduced toxicity toward MCF-10A cells, highlighting potential pharmacological advantages. Further, compound 5 altered the cell cycle and significantly increased apoptosis in MCF-7 cells, involving both early (41.7-fold) and late stages (33-fold), while moderately affecting necrotic signaling. The antitumor activity was linked to a notable reduction (4.78-fold) in topoisomerase IIβ expression. Molecular modeling indicated compound 5's strong affinity for EGFR, human EGF2 and topoisomerase II proteins. Conclusion: These findings highlight compound 5 as a multifaceted antitumor agent for breast cancer.

Exploring the Immunological Profile in Breast Cancer: Recent Advances in Diagnosis and Prognosis through Circulating Tumor Cells

This review offers a comprehensive exploration of the intricate immunological landscape of breast cancer (BC), focusing on recent advances in diagnosis and prognosis through the analysis of circulating tumor cells (CTCs). Positioned within the broader context of BC research, it underscores the pivotal role of the immune system in shaping the disease's progression. The primary objective of this investigation is to synthesize current knowledge on the immunological aspects of BC, with a particular emphasis on the diagnostic and prognostic potential offered by CTCs. This review adopts a thorough examination of the relevant literature, incorporating recent breakthroughs in the field. The methodology section succinctly outlines the approach, with a specific focus on CTC analysis and its implications for BC diagnosis and prognosis. Through this review, insights into the dynamic interplay between the immune system and BC are highlighted, with a specific emphasis on the role of CTCs in advancing diagnostic methodologies and refining prognostic assessments. Furthermore, this review presents objective and substantiated results, contributing to a deeper understanding of the immunological complexity in BC. In conclusion, this investigation underscores the significance of exploring the immunological profile of BC patients, providing valuable insights into novel advances in diagnosis and prognosis through the utilization of CTCs. The objective presentation of findings emphasizes the crucial role of the immune system in BC dynamics, thereby opening avenues for enhanced clinical management strategies.

The integrated on-chip isolation and detection of circulating tumour cells

Circulating tumour cells (CTCs) are cancer cells shed from a primary tumour which intravasate into the blood stream and have the potential to extravasate into distant tissues, seeding metastatic lesions. As such, they can offer important insight into cancer progression with their presence generally associated with a poor prognosis. The detection and enumeration of CTCs is, therefore, critical to guiding clinical decisions during treatment and providing information on disease state. CTC isolation has been investigated using a plethora of methodologies, of which immunomagnetic capture and microfluidic size-based filtration are the most impactful to date. However, the isolation and detection of CTCs from whole blood comes with many technical barriers, such as those presented by the phenotypic heterogeneity of cell surface markers, with morphological similarity to healthy blood cells, and their low relative abundance (∼1 CTC/1 billion blood cells). At present, the majority of reported methods dissociate CTC isolation from detection, a workflow which undoubtedly contributes to loss from an already sparse population. This review focuses on developments wherein isolation and detection have been integrated into a single-step, microfluidic configuration, reducing CTC loss, increasing throughput, and enabling an on-chip CTC analysis with minimal operator intervention. Particular attention is given to immune-affinity, microfluidic CTC isolation, coupled to optical, physical, and electrochemical CTC detection (quantitative or otherwise).

Soluble Periostin is a potential surveillance biomarker for early and long-term response to chemotherapy in advanced breast cancer

BACKGROUND

Noninvasive biomarkers for the assessment of response to chemotherapy in advanced breast cancer (BCa) are essential for optimized therapeutic decision-making. We evaluated the potential of soluble Periostin (POSTN) in circulation as a novel biomarker for chemotherapy efficacy monitoring.

METHODS

Two hundred and thirty-one patients with different stages of BCa were included. Of those patients, 58 patients with inoperable metastatic disease receiving HER2-targeted or non-targeted chemotherapy were enrolled to assess the performances of markers in recapitulating the chemotherapy efficacy assessed by imaging. POSTN, together with CA153 or CEA at different time points (C0, C2, and C4) were determined.

RESULTS

POSTN levels were significantly associated with tumor volume (P < 0.0001) and TNM stages (P < 0.0001) of BCa. For early monitoring, dynamics of POSTN could recapitulate the chemotherapy efficacy among all molecular subtypes (Cohen's weighted kappa = 0.638, P < 0.0001), much better than that of carcinoembryonic antigen (CEA) and cancer antigen 153 (CA15-3). For early partial response, superior performance of POSTN was observed (Cohen's weighted kappa = 0.827, P < 0.0001) in cases with baseline levels above 17.19 ng/mL. For long-term monitoring, the POSTN response was observed to be strongly consistent with the course of the disease. Moreover, progression free survival analysis showed that patients experienced a significant early decrease of POSTN tended to obtain more benefits from the treatments.

CONCLUSIONS

The current study suggests that soluble POSTN is an informative serum biomarker to complement the current clinical approaches for early and long-term chemotherapy efficacy monitoring in advanced BCa.

Simple Binding and Dissociation of a Sialoglycoprotein Using Boronic Acid-Modified Functional Interfaces on Microparticles

An overexpression of sialic acid is an indicator of metastatic cancer, and selective detection of sialic acid shows potential for cancer diagnosis. Boronic acid is a promising candidate for this purpose because of its ability to specifically bind to sialic acid under acidic conditions. Notably, the binding strength can be easily modulated by adjusting the pH, which allows for a simple dissociation of the bound sialic acid. In this study, we developed 5-boronopicolinic acid (5-BPA)-modified magnetic particles (BMPs) to selectively capture sialic acid biomolecules. We successfully captured fetuin, a well-known sialoglycoprotein, on BMPs at >104 molecules/particle using an acetate buffer (pH 5.0). Facile dissociation then occurred when the system was changed to a pH 7.6 phosphate buffer. This capture-and-release process could be repeated at least five times. Moreover, this system could enrich fetuin by more than 20 times. In summary, BMPs are functional particles for facile purification and concentration through the selective capture of sialic acid proteins and can improve detection sensitivity compared with conventional methods. This technology shows potential for the detection of sialic acid overexpression by biological particles.

Refining PD-1/PD-L1 assessment for biomarker-guided immunotherapy: A review

Anti-programmed cell death ligand 1 (anti-PD-L1)  immunotherapy is an increasingly crucial in cancer treatment. To date, the Federal Drug Administration (FDA) has approved four PD-L1 immunohistochemistry (IHC) staining protocols, commercially available in the form of "kits", facilitating testing for PD-L1 expression. These kits comprise four PD-L1 antibodies on two separate IHC platforms, each utilizing distinct, non-interchangeable scoring systems. Several factors, including tumor heterogeneity and the size of the tissue specimens assessed, can lead to PD-L1 status misclassification, potentially hindering the initiation of therapy. Therefore, the development of more accurate predictive biomarkers to distinguish between responders and non-responders prior to anti-PD-1/PD-L1 therapy warrants further research. Achieving this goal necessitates refining sampling criteria, enhancing current methods of PD-L1 detection, and deepening our understanding of the impact of additional biomarkers. In this article, we review potential solutions to improve the predictive accuracy of PD-L1 assessment in order to more precisely anticipate patients' responses to anti-PD-1/PD-L1 therapy, monitor disease progression and predict clinical outcomes.

Fibrin Stiffness Regulates Phenotypic Plasticity of Metastatic Breast Cancer Cells

The extracellular matrix (ECM)-regulated phenotypic plasticity is crucial for metastatic progression of triple negative breast cancer (TNBC). While ECM faithful cell-based models are available for in situ and invasive tumors, such as cell aggregate cultures in reconstituted basement membrane and in collagenous gels, there are no ECM faithful models for metastatic circulating tumor cells (CTCs). Such models are essential to represent the stage of metastasis where clinical relevance and therapeutic opportunities are significant. Here, CTC-like DU4475 TNBC cells are cultured in mechanically tunable 3D fibrin hydrogels. This is motivated, as in circulation fibrin aids CTC survival by forming a protective coating reducing shear stress and immune cell-mediated cytotoxicity and promotes several stages of late metastatic processes at the interface between circulation and tissue. This work shows that fibrin hydrogels support DU4475 cell growth, resulting in spheroid formation. Furthermore, increasing fibrin stiffness from 57 to 175 Pa leads to highly motile, actin and tubulin containing cellular protrusions, which are associated with specific cell morphology and gene expression patterns that markedly differ from basement membrane or suspension cultures. Thus, mechanically tunable fibrin gels reveal specific matrix-based regulation of TNBC cell phenotype and offer scaffolds for CTC-like cells with better mechano-biological properties than liquid.

Clinical value of folate receptor-positive circulating tumor cells in patients with esophageal squamous cell carcinomas: a retrospective study

BACKGROUND

The aim of the study is to explore the role of preoperative folate receptor-positive circulating tumor cell (FR+CTC) levels in predicting disease-free survival (DFS) and overall survival (OS) in patients with esophageal squamous cell carcinomas (ESCC).

METHODS

Three ml blood samples were prospectively drawn from ESCC patients, and ligand-targeted polymerase chain reaction (LT-PCR) was used for the quantification of FR+CTCs. Other serum indicators were measured by traditional methods. Clinicopathological characteristics were obtained from the hospital medical record system, DFS and OS data were obtained by follow-up. The correlation between clinico-pathological characteristics, DFS, and OS and FR+CTCs were analyzed, respectively. Risk factors potentially affecting DFS and OS were explored by Cox regression analysis.

RESULTS

there were no significant correlations between FR+CTCs and patient age, sex, albumin, pre-albumin, C-reactive protein (CRP), ferritin and CRP/Albumin ratio, tumor size, grade of differentiation, lymph node metastasis, TNM stage, perineural invasion/vessel invasion (all P > 0.05). Nevertheless, preoperative FR+CTCs were an independent prognostic factor for DFS (HR 2.7; 95% CI 1.31-, P = 0.007) and OS (HR 3.37; 95% CI 1.06-, P = 0.04). DFS was significantly shorter for patients with post-operative FR+CTCs ≥ 17.42 FU/3ml compared with patients < 17.42 FU/3ml (P = 0.0012). For OS, it was shorter for patients with FR+CTCs ≥ 17.42 FU/3ml compared with patients < 17.42 FU/3ml, however, the difference did not reach statistical significance (P = 0.51).

CONCLUSIONS

ESCC patients with high FR+CTCs tend to have a worse prognosis. FR+CTCs may monitor the recurrence of cancers in time, accurately assess patient prognosis, and guide clinical decision-making.

TRIAL REGISTRATION

The study was approved by the Sichuan Cancer Hospital & Institute Ethics Committee (No. SCCHEC-02-2022-050).

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.

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.

A bibliometric and visualized study on global trends of breast augmentation complications, 2011-2021

Background

Women undergo breast augmentation surgery for a variety of reasons, but surgical complications can seriously affect patient outcomes and quality of life, making it a hot research topic. Although a large body of literature exists in this field, a lack of systemic generalization hinders the ability to guide clinical practice. We aimed to identify the current research hotspots and common surgical approaches of breast augmentation and to predict future research hotspots by analyzing the literature of the past 10 years.

Methods

All relevant literature on breast augmentation complications were screened in the Web of Science (WoS) platform from 2011 to 2021. We analyzed the research within this field using the software programs VOSviewer and CiteSpace.

Results

In total, 2,798 publications were selected. The United States ranked first in the world (1,173 articles), followed by Italy (243 articles), and the United Kingdom (208 articles). Memorial Sloan Kettering Cancer Center was the institution with the most publications, but the academic achievements of Harvard were the most recognized. Plastic and Reconstructive Surgery was the most prominent of all journals in terms of both the number and quality of the articles published. Albornoz was the hub author in the co-citation network. Keyword cluster analysis showed that capsular contracture, breast cancer, and postoperative nausea, among others, were the hotspots and trends of research in recent years.

Conclusions

This study comprehensively summarized and analyzed the research trends of breast augmentation complications worldwide. Capsular contracture and postoperative nausea are current research hotspots. Periareolar incision and the breast crease incision are the most common incision approaches. Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a future research hotspot.

Bibliometric analysis of global research on breast reconstruction after mastectomy for breast cancer from 2011 to 2021

BACKGROUND

Breast cancer is the most common malignant tumor in the world, and most patients require a mastectomy. Women who have undergone mastectomy often suffer from breast loss that seriously affects their daily life, and breast reconstruction is not only beneficial to patient's quick recovery after surgery, but also their mental health. So, in recent years, more and more female breast cancer patients are receiving breast reconstruction surgery. We aim to map hot trends in breast reconstruction after mastectomy for breast cancer and provide directions for future research.

METHODS

We screened all literature (2011-2021) on breast reconstruction after mastectomy for breast cancer from The Web of Science Core Collection (WoSCC) and analyzed research trends in this field using Vosviewer and CiteSpace.

RESULTS

Based on the search results, a total of 3404 articles related to breast reconstruction after mastectomy for breast cancer were screened. The US (n = 1371) is the country with the highest number of articles, followed by Italy (n = 282) and the UK (n = 277). Harvard University (n = 183) was the institution with the highest number of publications, followed by the University of Texas (n = 141) and Memorial Sloan Kettering Cancer Center (n = 136). Plastic and Reconstructive Surgery is the most published journal in the field. Pusic AL is the most published author in the field, while Matros E is the most cited author on average. Cluster analysis showed that breast reconstruction after mastectomy for breast cancer is a hot topic of research by scholars, and more and more experts recommend breast reconstruction for breast cancer patients.

CONCLUSIONS

This study comprehensively summarizes and analyzes global research trends in breast reconstruction after mastectomy for breast cancer. In the past 10 years, there has been a significant increase in relevant high-quality publications in this field, and the field of breast reconstruction after mastectomy for breast cancer has a promising future.

Marker-free characterization of full-length transcriptomes of single live circulating tumor cells

The identification and characterization of circulating tumor cells (CTCs) are important for gaining insights into the biology of metastatic cancers, monitoring disease progression, and medical management of the disease. The limiting factor in the enrichment of purified CTC populations is their sparse availability, heterogeneity, and altered phenotypes relative to the primary tumor. Intensive research both at the technical and molecular fronts led to the development of assays that ease CTC detection and identification from peripheral blood. Most CTC detection methods based on single-cell RNA sequencing (scRNA-seq) use a mix of size selection, marker-based white blood cell (WBC) depletion, and antibodies targeting tumor-associated antigens. However, the majority of these methods either miss out on atypical CTCs or suffer from WBC contamination. We present unCTC, an R package for unbiased identification and characterization of CTCs from single-cell transcriptomic data. unCTC features many standard and novel computational and statistical modules for various analyses. These include a novel method of scRNA-seq clustering, named deep dictionary learning using k-means clustering cost (DDLK), expression-based copy number variation (CNV) inference, and combinatorial, marker-based verification of the malignant phenotypes. DDLK enables robust segregation of CTCs and WBCs in the pathway space, as opposed to the gene expression space. We validated the utility of unCTC on scRNA-seq profiles of breast CTCs from six patients, captured and profiled using an integrated ClearCell FX and Polaris workflow that works by the principles of size-based separation of CTCs and marker-based WBC depletion.

Technologies for Viable Circulating Tumor Cell Isolation

The spread of tumor cells throughout the body by traveling through the bloodstream is a critical step in metastasis, which continues to be the main cause of cancer-related death. The detection and analysis of circulating tumor cells (CTCs) is important for understanding the biology of metastasis and the development of antimetastatic therapy. However, the isolation of CTCs is challenging due to their high heterogeneity and low representation in the bloodstream. Different isolation methods have been suggested, but most of them lead to CTC damage. However, viable CTCs are an effective source for developing preclinical models to perform drug screening and model the metastatic cascade. In this review, we summarize the available literature on methods for isolating viable CTCs based on different properties of cells. Particular attention is paid to the importance of in vitro and in vivo models obtained from CTCs. Finally, we emphasize the current limitations in CTC isolation and suggest potential solutions to overcome them.

Association of circulating tumor cell-white blood cell clusters with survival outcomes in patients with colorectal cancer after curative intent surgery

BACKGROUND

The analysis of circulating tumor cell-associated white blood cell (CTC-WBC) clusters represented the progress in the liquid biopsy of malignant tumors, however, related research in patients with colorectal cancer is still absent.

METHODS

To explore associations between CTC-WBC clusters and the prognosis of these patients, we conducted an independent cohort of 329 colorectal cancer patients after curative intent surgery and pre-operative CTC detection in Nanfang Hospital, Southern Medical University, Guangzhou, China between January 1, 2017, and September 31, 2019. The primary cohort referred to patients with CTC-WBC clusters positive. The control cohort was defined as those with exclusively CTCs positive. CTCs were enriched and distinguished by The CanPatrol™ system (SurExam, China). The Kaplan-Meier curve was used to compare the progressive-free survival (PFS) and overall survival (OS) between two groups. The COX regression model was used to assess the predictive value of CTC-WBC clusters.

RESULTS

Sixty three patients presented CTC-WBC clusters positive (CTC-WBC group) and 266 patients showed solely CTCs (CTC group). The number of CTCs was significantly different between two groups (P < 0.001) and the rest of clinical characteristics were not markedly associated with the presence of CTC-WBC clusters. Kaplan-Meier curves of PFS and OS exhibited that the CTC-WBC group had significantly shorter PFS (P = 0.011), while not for OS. The multivariate model further suggested that the CTC-WBC clusters (Hazard Ratio = 1.89, 95% Confidence Interval 1.02-3.51, P = 0.042) was an independent predictor for the PFS of in post-operation CRC patients.

CONCLUSION

The CTC-WBC cluster is significantly associated with recurrence after operation in CRC patients. This finding facilitates the evaluation of this indicator in tumor progression.

Towards the Search for Potential Biomarkers in Osteosarcoma: State-of-the-Art and Translational Expectations

Osteosarcoma represents a rare cause of cancer in the general population, accounting for <1% of malignant neoplasms globally. Nonetheless, it represents the main cause of malignant bone neoplasm in children, adolescents and young adults under 20 years of age. It also presents another peak of incidence in people over 50 years of age and is associated with rheumatic diseases. Numerous environmental risk factors, such as bone diseases, genetics and a history of previous neoplasms, have been widely described in the literature, which allows monitoring a certain group of patients. Diagnosis requires numerous imaging tests that make it possible to stratify both the local involvement of the disease and its distant spread, which ominously determines the prognosis. Thanks to various clinical trials, the usefulness of different chemotherapy regimens, radiotherapy and surgical techniques with radical intent has now been demonstrated; these represent improvements in both prognosis and therapeutic approaches. Osteosarcoma patients should be evaluated in reference centres by multidisciplinary committees with extensive experience in proper management. Although numerous genetic and rheumatological diseases and risk factors have been described, the use of serological, genetic or other biomarkers has been limited in clinical practice compared to other neoplasms. This limits both the initial follow-up of these patients and screening in populations at risk. In addition, we cannot forget that the diagnosis is mainly based on the direct biopsy of the lesion and imaging tests, which illustrates the need to study new diagnostic alternatives. Therefore, the purpose of this study is to review the natural history of the disease and describe the main biomarkers, explaining their clinical uses, prognosis and limitations.

Quantitative Phase Imaging Detecting the Hypoxia-Induced Patterns in Healthy and Neoplastic Human Colonic Epithelial Cells

Hypoxia is a frequent phenomenon during carcinogenesis and may lead to functional and structural changes in proliferating cancer cells. Colorectal cancer (CRC) is one of the most common neoplasms in which hypoxia is associated with progression. The aim of this study was to assess the optical parameters and microanatomy of CRC and the normal intestinal epithelium cells using the digital holotomography (DHT) method. The examination was conducted on cancer (HT-29, LoVo) and normal colonic cells (CCD-18Co) cultured in normoxic and hypoxic environments. The assessment included optical parameters such as the refractive index (RI) and dry mass as well as the morphological features. Hypoxia decreased the RI in all cells as well as in their cytoplasm, nucleus, and nucleoli. The opposite tendency was noted for spheroid-vesicular structures, where the RI was higher for the hypoxic state. The total volume of hypoxic CCD-18Co and LoVo cells was decreased, while an increase in this parameter was observed for HT-29 cells. Hypoxia increased the radius and cell volume, including the dry mass of the vesicular content. The changes in the optics and morphology of hypoxic cells may suggest the possibility of using DHT in the detection of circulating tumor cells (CTCs).

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.

Clinical Relevancy of Circulating Tumor Cells in Breast Cancer: Epithelial or Mesenchymal Characteristics, Single Cells or Clusters?

Metastatic breast cancer (MBC) is typically an incurable disease with high mortality rates; thus, early identification of metastatic features and disease recurrence through precise biomarkers is crucial. Circulating tumor cells (CTCs) consisting of heterogeneous subpopulations with different morphology and genetic, epigenetic, and gene expression profiles represent promising candidate biomarkers for metastatic potential. The experimentally verified role of epithelial-to-mesenchymal transition in cancer dissemination has not been clearly described in BC patients, but the stemness features of CTCs strongly contributes to metastatic potency. Single CTCs have been shown to be protected in the bloodstream against recognition by the immune system through impaired interactions with T lymphocytes and NK cells, while associations of heterotypic CTC clusters with platelets, leucocytes, neutrophils, tumor-associated macrophages, and fibroblasts improve their tumorigenic behavior. In addition to single CTC and CTC cluster characteristics, we reviewed CTC evaluation methods and clinical studies in early and metastatic BCs. The variable CTC tests were developed based on specific principles and strategies. However, CTC count and the presence of CTC clusters were shown to be most clinically relevant in existing clinical trials. Despite the known progress in CTC research and sampling of BC patients, implementation of CTCs and CTC clusters in routine diagnostic and treatment strategies still requires improvement in detection sensitivity and precise molecular characterizations, focused predominantly on the role of CTC clusters for their higher metastatic potency.

Circulating Neuroendocrine Tumor Biomarkers: Past, Present and Future

Neuroendocrine tumors are a heterogeneous group of neoplasms originating from the diffuse endocrine system. Depending on primary location and hormonal status, they range in terms of clinical presentation, prognosis and treatment. Functional tumors often develop symptoms indicating an excess of hormones produced by the neoplasm (exempli gratia insulinoma, glucagonoma and VIPoma) and can be diagnosed using monoanalytes. For non-functional tumors (inactive or producing insignificant amounts of hormones), universal biomarkers have not been established. The matter remains an important unmet need in the field of neuroendocrine tumors. Substances researched over the years, such as chromogranin A and neuron-specific enolase, lack the desired sensitivity and specificity. In recent years, the potential use of Circulating Tumor Cells or multianalytes such as a circulating microRNA and NETest have been widely discussed. They offer superior diagnostic parameters in comparison to traditional biomarkers and depict disease status in a more comprehensive way. Despite a lot of promise, no international standards have yet been developed regarding their routine use and clinical application. In this literature review, we describe the analytes used over the years and cover novel biomarkers that could find a use in the future. We discuss their pros and cons while showcasing recent advances in the field of neuroendocrine tumor biomarkers.

From rough to precise: PD-L1 evaluation for predicting the efficacy of PD-1/PD-L1 blockades

Developing biomarkers for accurately predicting the efficacy of immune checkpoint inhibitor (ICI) therapies is conducive to avoiding unwanted side effects and economic burden. At the moment, the quantification of programmed cell death ligand 1 (PD-L1) in tumor tissues is clinically used as one of the combined diagnostic assays of response to anti-PD-1/PD-L1 therapy. However, the current assays for evaluating PD-L1 remain imperfect. Recent studies are promoting the methodologies of PD-L1 evaluation from rough to precise. Standardization of PD-L1 immunohistochemistry tests is being promoted by using optimized reagents, platforms, and cutoff values. Combining novel in vivo probes with PET or SPECT will probably be of benefit to map the spatio-temporal heterogeneity of PD-L1 expression. The dynamic change of PD-L1 in the circulatory system can also be realized by liquid biopsy. Consider PD-L1 expressed on non-tumor (immune and non-immune) cells, and optimized combination detection indexes are further improving the accuracy of PD-L1 in predicting the efficacy of ICIs. The combinations of artificial intelligence with novel technologies are conducive to the intelligence of PD-L1 as a predictive biomarker. In this review, we will provide an overview of the recent progress in this rapidly growing area and discuss the clinical and technical challenges.

Molecular Biomarkers in Cancer

Molecular cancer biomarkers are any measurable molecular indicator of risk of cancer, occurrence of cancer, or patient outcome. They may include germline or somatic genetic variants, epigenetic signatures, transcriptional changes, and proteomic signatures. These indicators are based on biomolecules, such as nucleic acids and proteins, that can be detected in samples obtained from tissues through tumor biopsy or, more easily and non-invasively, from blood (or serum or plasma), saliva, buccal swabs, stool, urine, etc. Detection technologies have advanced tremendously over the last decades, including techniques such as next-generation sequencing, nanotechnology, or methods to study circulating tumor DNA/RNA or exosomes. Clinical applications of biomarkers are extensive. They can be used as tools for cancer risk assessment, screening and early detection of cancer, accurate diagnosis, patient prognosis, prediction of response to therapy, and cancer surveillance and monitoring response. Therefore, they can help to optimize making decisions in clinical practice. Moreover, precision oncology is needed for newly developed targeted therapies, as they are functional only in patients with specific cancer genetic mutations, and biomarkers are the tools used for the identification of these subsets of patients. Improvement in the field of cancer biomarkers is, however, needed to overcome the scientific challenge of developing new biomarkers with greater sensitivity, specificity, and positive predictive value.

Circulating Exosome Cargoes Contain Functionally Diverse Cancer Biomarkers: From Biogenesis and Function to Purification and Potential Translational Utility

Although diagnostic and therapeutic treatments of cancer have tremendously improved over the past two decades, the indolent nature of its symptoms has made early detection challenging. Thus, inter-disciplinary (genomic, transcriptomic, proteomic, and lipidomic) research efforts have been focused on the non-invasive identification of unique "silver bullet" cancer biomarkers for the design of ultra-sensitive molecular diagnostic assays. Circulating tumor biomarkers, such as CTCs and ctDNAs, which are released by tumors in the circulation, have already demonstrated their clinical utility for the non-invasive detection of certain solid tumors. Considering that exosomes are actively produced by all cells, including tumor cells, and can be found in the circulation, they have been extensively assessed for their potential as a source of circulating cell-specific biomarkers. Exosomes are particularly appealing because they represent a stable and encapsulated reservoir of active biological compounds that may be useful for the non-invasive detection of cancer. T biogenesis of these extracellular vesicles is profoundly altered during carcinogenesis, but because they harbor unique or uniquely combined surface proteins, cancer biomarker studies have been focused on their purification from biofluids, for the analysis of their RNA, DNA, protein, and lipid cargoes. In this review, we evaluate the biogenesis of normal and cancer exosomes, provide extensive information on the state of the art, the current purification methods, and the technologies employed for genomic, transcriptomic, proteomic, and lipidomic evaluation of their cargoes. Our thorough examination of the literature highlights the current limitations and promising future of exosomes as a liquid biopsy for the identification of circulating tumor biomarkers.

The Discovery of Novel Circulating Cancer-Related Cells in Circulation Poses New Challenges to Microfluidic Devices for Enrichment and Detection

Circulating tumor cells (CTCs) enumeration has been widely used as a surrogate predictive marker for early diagnoses, the evaluation of chemotherapy efficacy, and cancer prognosis. Microfluidic technologies for CTCs enrichment and detection have been developed and commercialized as automation platforms. Currently, in addition to CTCs, some new types of circulating cancer-related cells (e.g., CCSCs, CTECs, CAMLs, and heterotypic CTC clusters) in circulation are also reported to be correlated to cancer diagnosis, metastasis, or prognosis. And they widely differ from the conventional CTCs in positive markers, cellular morphology, or size, which presents a new technological challenge to microfluidic devices that use affinity-based capture methods or size-based filtration methods for CTCs detection. This review focuses on the biological and physical properties as well as clinical significance of the novel circulating cancer-related cells, and discusses the challenges of their discovery to microfluidic chip for enrichment. Finally, the current challenges of CTCs detection in clinical application and future opportunities are also discussed.

Optimal whole blood dilution protocol for preprocessing samples prior to circulating tumor cell capture by size-based isolation

BACKGROUND

This study compared whole blood dilution versus density gradient centrifugation for pre-processing blood samples prior to circulating tumor cell (CTC) capture on the efficiency of CTC separation by size-based isolation.

MATERIALS AND METHODS

Whole blood from a healthy volunteer spiked with SKBR3 cells was used to optimize the whole blood dilution protocol for sample volume, dilution ratio, and paraformaldehyde (PFA) concentration. Whole blood from healthy volunteers spiked with SKBR3, A549, or PC3 cells, and whole blood from patients with advanced gastric, esophageal, or liver cancer, was used to compare pre-processing by the optimal whole blood dilution protocol with density-gradient centrifugation. All statistical evaluations were performed using Student t test of the Statistical Package for Social Sciences (SPSS version 17.0).

RESULTS

In blood samples from healthy volunteers, spiked SKBR3 cell recovery rates were highest in 5 ml of whole blood, diluted with 2.5 ml buffer, and fixed with 0.2% PFA, and spiked SKBR3, A549, and PC3 cell recovery rates from 5 ml whole blood were significantly greater when using the optimized whole blood dilution protocol (87.67% ± 1.76%, 79.50% ± 0.50% and 71.83% ± 1.04%, respectively) compared to density-gradient centrifugation (46.83 ± 1.76%, 37.00 ± 1.50% and 41.00 ± 1.50%, respectively).

Clinical Applications of Classical and Novel Biological Markers of Pancreatic Cancer

The incidence and prevalence of pancreatic adenocarcinoma have increased in recent years. Pancreatic cancer is the seventh leading cause of cancer death, but it is projected to become the second leading cause of cancer-related mortality by 2040. Most patients are diagnosed in an advanced stage of the disease, with very limited 5-year survival. The discovery of different tissue markers has elucidated the underlying pathophysiology of pancreatic adenocarcinoma and allowed stratification of patient risk at different stages and assessment of tumour recurrence. Due to the invasive capacity of this tumour and the absence of screening markers, new immunohistochemical and serological markers may be used as prognostic markers for recurrence and in the study of possible new therapeutic targets because the survival of these patients is low in most cases. The present article reviews the currently used main histopathological and serological markers and discusses the main characteristics of markers under development.

The double agents in liquid biopsy: promoter and informant biomarkers of early metastases in breast cancer

Breast cancer continues to be a major global problem with significant mortality associated with advanced stage and metastases at clinical presentation. However, several findings suggest that metastasis is indeed an early occurrence. The standard diagnostic techniques such as invasive core needle biopsy, serological protein marker assays, and non-invasive radiological imaging do not provide information about the presence and molecular profile of small fractions of early metastatic tumor cells which are prematurely dispersed in the circulatory system. These circulating tumor cells (CTCs) diverge from the primary tumors as clusters with a defined secretome comprised of circulating cell-free nucleic acids and small microRNAs (miRNAs). These circulatory biomarkers provide a blueprint of the mutational profile of the tumor burden and tumor associated alterations in the molecular signaling pathways involved in oncogenesis. Amidst the multitude of circulatory biomarkers, miRNAs serve as relatively stable and precise biomarkers in the blood for the early detection of CTCs, and promote step-wise disease progression by executing paracrine signaling that transforms the microenvironment to guide the metastatic CTCs to anchor at a conducive new organ. Random sampling of easily accessible patient blood or its serum/plasma derivatives and other bodily fluids collectively known as liquid biopsy (LB), forms an efficient alternative to tissue biopsies. In this review, we discuss in detail the divergence of early metastases as CTCs and the involvement of miRNAs as detectable blood-based diagnostic biomarkers that warrant a timely screening of cancer, serial monitoring of therapeutic response, and the dynamic molecular adaptations induced by miRNAs on CTCs in guiding primary and second-line systemic therapy.

Chick Chorioallantoic Membrane (CAM) Assays as a Model of Patient-Derived Xenografts from Circulating Cancer Stem Cells (cCSCs) in Breast Cancer Patients

Simple Summary

Circulating cancer cells—and in particular their very rare subpopulation, circulating cancer stem cells (cCSCs)—are responsible for recurrence and metastasis. In this study, we present a novel process in which patient-derived xenograft (PDX) can be harvested on chorioallantoic membrane (CAM) from circulating cancer stem cells. In our opinion, the CAM-based PDX model using circulating cancer stem cells can provide a fast, low-cost, easy-to-use, and efficient preclinical platform for drug screening, therapy optimization, and biomarker discovery.

Abstract

Background: cCSCs are a small subset of circulating tumor cells with cancer stem cell features: resistance to cancer treatments and the capacity for generating metastases. PDX are an appreciated tool in oncology, providing biologically meaningful models of many cancer types, and potential platforms for the development of precision oncology approaches. Commonly, mouse models are used for the in vivo assessment of potential new therapeutic targets in cancers. However, animal models are costly and time consuming. An attractive alternative to such animal experiments is the chicken chorioallantoic membrane assay. Methods: In this study, primary cultures from cCSCs were established using the sphere-forming assay. Subsequently, tumorspheres were transplanted onto the CAM membrane of fertilized chicken eggs to form secondary microtumors. Results: We have developed an innovative in vitro platform for cultivation of cCSCs from peripheral blood of cancer patients. The number of tumorspheres increased significantly with tumor progression and aggressiveness of primary tumor. The number of tumorspheres was positively correlated with Ki-67, Her2 status, and grade score in primary breast tumors. The grafting of tumorspheres onto the CAM was successful and positively correlated with aggressiveness and proliferation capacity of the primary tumor. These tumors pathologically closely resembled the primary tumor. Conclusions: The number of tumorspheres cultured from peripheral blood and the success rate of establishing PDX directly reflect the aggressiveness and proliferation capacity of the primary tumor. A CAM-based PDX model using cCSC provides a fast, low-cost, easy to handle, and powerful preclinical platform for drug screening, therapy optimization, and biomarker discovery.

Basic Principles and Recent Advances in Magnetic Cell Separation

Magnetic cell separation has become a key methodology for the isolation of target cell populations from biological suspensions, covering a wide spectrum of applications from diagnosis and therapy in biomedicine to environmental applications or fundamental research in biology. There now exists a great variety of commercially available separation instruments and reagents, which has permitted rapid dissemination of the technology. However, there is still an increasing demand for new tools and protocols which provide improved selectivity, yield and sensitivity of the separation process while reducing cost and providing a faster response. This review aims to introduce basic principles of magnetic cell separation for the neophyte, while giving an overview of recent research in the field, from the development of new cell labeling strategies to the design of integrated microfluidic cell sorters and of point-of-care platforms combining cell selection, capture, and downstream detection. Finally, we focus on clinical, industrial and environmental applications where magnetic cell separation strategies are amongst the most promising techniques to address the challenges of isolating rare cells.

Long-term Survival After Diverse Therapeutic Modalities in Malignant Phyllodes Tumors of the Breast

Background and Objects: Malignant phyllodes tumor of the breast (MPTB) is a rare tumor for which surgery or surgery combined with radiotherapy (RT) is the primary treatment method. However, recently, the therapeutic effect of RT on MPTB has been controversial. We aimed to explore the role of RT, chemotherapy (CT), and surgical modalities in patients with MPTB. Methods: The Surveillance, Epidemiology, and End Results (SEER) database was used to select patients with MPTB who met the criteria between 2010 and 2018. Kaplan–Meier curves and Cox proportional risk regression models were used to analyze the effects of RT on MPTB patients. Based on this, we compared the effects of breast-conserving surgery (BSC) and mastectomy on the postoperative survival of MPTB. Results: A total of 298 patients with MPTB were included in this study. RT was received by 22.1% (n  =  66) of the patients while 77.9% (n  =  232) did not receive RT. CT was received by 4.7% (n  =  14) patients while 95.3% (n  =  284) did not receive CT. According to Kaplan–Meier curves, RT and CT combined resulted in a decrease in breast cancer-specific survival (BCSS) and overall survival (OS) compared to patients who did not receive RT. Mastectomy improved the OS and BCSS of the patients more than BCS). The findings of univariate and multivariate Cox regression analyses suggested that “distant metastasis”, “tumor grade” and “number of positive lymph node biopsies” affected OS of breast cancer, while “distant metastasis”, “tumor grade”, “surgery combined with radiotherapy/surgery”, and “radiotherapy/chemotherapy or not”, had a significant effect on BCSS. Conclusion: RT and CT did not significantly improve the long-term survival of MPTB patients. Mastectomy improved OS and BCSS of the patient more than BCS. RT in an early stage improved early prognosis moderately in MPTB patients with tumor diameter less than 50 mm.

The miR-200 Family of microRNAs: Fine Tuners of Epithelial-Mesenchymal Transition and Circulating Cancer Biomarkers

The miR-200 family of microRNAs (miRNAs) includes miR-200a, miR-200b, miR-200c, miR-141 and miR-429, five evolutionarily conserved miRNAs that are encoded in two clusters of hairpin precursors located on human chromosome 1 (miR-200b, miR-200a and miR-429) and chromosome 12 (miR-200c and miR-141). The mature -3p products of the precursors are abundantly expressed in epithelial cells, where they contribute to maintaining the epithelial phenotype by repressing expression of factors that favor the process of epithelial-to-mesenchymal transition (EMT), a key hallmark of oncogenic transformation. Extensive studies of the expression and interactions of these miRNAs with cell signaling pathways indicate that they can exert both tumor suppressor- and pro-metastatic functions, and may serve as biomarkers of epithelial cancers. This review provides a summary of the role of miR-200 family members in EMT, factors that regulate their expression, and important targets for miR-200-mediated repression that are involved in EMT. The second part of the review discusses the potential utility of circulating miR-200 family members as diagnostic/prognostic biomarkers for breast, colorectal, lung, ovarian, prostate and bladder cancers.

Current Technologies for RNA-Directed Liquid Diagnostics

There is unequivocal acceptance of the variety of enormous potential liquid nucleic acid-based diagnostics seems to offer. However, the existing controversies and the increased awareness of RNA-based techniques in society during the current global COVID-19 pandemic have made the readiness of liquid nucleic acid-based diagnostics for routine use a matter of concern. In this regard-and in the context of oncology-our review presented and discussed the status quo of RNA-based liquid diagnostics. We summarized the technical background of the available assays and benchmarked their applicability against each other. Herein, we compared the technology readiness level in the clinical context, economic aspects, implementation as part of routine point-of-care testing as well as performance power. Since the preventive care market is the most promising application sector, we also investigated whether the developments predominantly occur in the context of early disease detection or surveillance of therapy success. In addition, we provided a careful view on the current biotechnology investment activities in this sector to indicate the most attractive strategies for future economic success. Taken together, our review shall serve as a current reference, at the interplay of technology, clinical use and economic potential, to guide the interested readers in this rapid developing sector of precision medicine.