Dynamic changes of Receptor activator of nuclear factor-κB expression in Circulating Tumor Cells during Denosumab predict treatment effectiveness in Metastatic Breast Cancer

Knowledge-map and research trends of circulating tumor cells in breast cancer: a scientometric analysis

Assessing circulating tumor cells (CTCs) in early-stage breast cancer patients can help identify relapse risk for timely interventions. Molecular analysis of CTCs can reveal vulnerabilities for personalized treatment options in metastatic breast cancer. This study aims to summarize CTCs in breast cancer research understanding and evaluate research trends. Extracted from the Web of Science Core Collection, publications on CTCs in breast cancer studies spanning from January 1, 2008, to December 21, 2023, were included. Co-authorships, references, and keywords were analyzed using Bibliometrix R packages and VOSviewer software. References and keywords burst detection were conducted with CiteSpace, and BICOMB was utilized to generate high-frequency keyword layouts. Biclustering analysis of the binary co-keyword matrix was performed using gCLUTO. 1747 articles focusing on CTCs in breast cancer were identified. The USA and the University of Texas MD Anderson Cancer Center demonstrated the highest productivity at the national and institutional levels, respectively. The journal "CANCERS" had the highest publication outputs on this subject. Pantel K emerged as the foremost author with the highest publication and co-citation counts. Analysis of co-keywords unveiled five prominent research areas concerning CTCs in breast cancer. The prognostic and predictive roles of CTCs in breast cancer have substantial implications for clinical practice. Nevertheless, precise assessment of CTCs, encompassing its quantities and attributes through advanced technologies, and its role in detecting minimal residual disease in breast cancer, continue to pose notable challenges. In conclusion, recent advancements and trends in CTCs research in breast cancer are examined through scientometric analysis in this study. The results provide valuable insights for the formulation of novel approaches in CTCs research, emphasizing the current research frontiers.

Circulating receptor activator of nuclear factor kappa-B ligand (RANKL) levels predict response to immune checkpoint inhibitors in advanced non-small cell lung cancer (NSCLC)

BACKGROUND

Receptor activator of nuclear factor kappa-B ligand (RANKL) can directly promote tumor growth and indirectly support tumor immune evasion by altering the tumor microenvironment and immune cell responses. This study aimed to assess the prognostic significance of soluble RANKL in patients with advanced non-small cell lung cancer (NSCLC) receiving programmed cell death 1 (PD1)/programmed death-ligand 1 (PDL1) checkpoint inhibitor therapy.

METHODS

Plasma RANKL levels were measured in 100 patients with advanced NSCLC without bone metastases undergoing monotherapy with PD1/PDL1 checkpoint inhibitors. To establish the optimal cut-off value, we used the Cutoff Finder package in R. Survival curves for four distinct patient groups, according to their RANKL and PDL1 levels (high or low), were generated using the Kaplan-Meier method and compared with the log-rank test. The Cox regression model calculated HRs and 95% CIs for overall survival (OS) and progression-free survival (PFS).

RESULTS

The optimal RANKL cut-off was established at 280.4 pg/mL, categorizing patients into groups with high or low RANKL levels. A significant association was observed between increased RANKL concentrations and decreased survival rates at 24 months, only within the subgroup expressing high levels of PDL1 (p=0.002). Additionally, low RANKL levels in conjunction with elevated PDL1 expression correlated with improved PFS (median 22 months, 95% CI 6.70 to 50 vs median 4 months, 95% CI 3.0 to 7.30, p=0.009) and OS (median 26 months, 95% CI 20 to not reached vs median 7 months, 95% CI 6 to 13, p=0.003), indicating RANKL's potential as an indicator of adverse prognosis in these patients. Multivariate analysis identified RANKL as an independent negative prognostic factor for both PFS and OS, regardless of other clinicopathological features.

CONCLUSION

These results highlight the prognostic and predictive value of RANKL specifically in patients with high PDL1 expression.

Beyond boundaries: unraveling innovative approaches to combat bone-metastatic cancers

Evidence demonstrated that bones, liver, and lungs are the most common metastasis sites in some human malignancies, especially in prostate and breast cancers. Bone is the third most frequent target for spreading tumor cells among these organs and tissues. Patients with bone-metastatic cancers face a grim prognosis characterized by short median survival time. Current treatments have proven insufficient, as they can only inhibit metastasis or tumor progression within the bone tissues rather than providing a curative solution. Gaining a more profound comprehension of the interplay between tumor cells and the bone microenvironment (BME) is of utmost importance in tackling this issue. This knowledge will pave the way for developing innovative diagnostic and therapeutic approaches. This review summarizes the mechanisms underlying bone metastasis and discusses the clinical aspects of this pathologic condition. Additionally, it highlights emerging therapeutic interventions aimed at enhancing the quality of life for patients affected by bone-metastatic cancers. By synthesizing current research, this review seeks to shed light on the complexities of bone metastasis and offer insights for future advancements in patient care.

Circulating Tumour Cells in the Prediction of Bone Metastasis

Bone is the most common organ for the development of metastases in many primary tumours, including those of the breast, prostate and lung. In most cases, bone metastasis is incurable, and treatment is predominantly palliative. Much research has focused on the role of Circulating Tumour Cells (CTCs) in the mechanism of metastasis to the bone, and methods have been developed to isolate and count CTCs from peripheral blood. Several methods are currently being used in the study of CTCs, but only one, the CellSearchTM system has been approved by the United States Food and Drug Administration for clinical use. This review summarises the advantages and disadvantages, and outlines which clinical studies have used these methods. Studies have found that CTC numbers are predictive of bone metastasis in breast, prostate and lung cancer. Further work is required to incorporate information on CTCs into current staging systems to guide treatment in the prevention of tumour progression into bone.

The Diversity of Liquid Biopsies and Their Potential in Breast Cancer Management

Analyzing blood as a so-called liquid biopsy in breast cancer (BC) patients has the potential to adapt therapy management. Circulating tumor cells (CTCs), extracellular vesicles (EVs), cell-free DNA (cfDNA) and other blood components mirror the tumoral heterogeneity and could support a range of clinical decisions. Multi-cancer early detection tests utilizing blood are advancing but are not part of any clinical routine yet. Liquid biopsy analysis in the course of neoadjuvant therapy has potential for therapy (de)escalation.Minimal residual disease detection via serial cfDNA analysis is currently on its way. The prognostic value of blood analytes in early and metastatic BC is undisputable, but the value of these prognostic biomarkers for clinical management is controversial. An interventional trial confirmed a significant outcome benefit when therapy was changed in case of newly emerging cfDNA mutations under treatment and thus showed the clinical utility of cfDNA analysis for therapy monitoring. The analysis of PIK3CA or ESR1 variants in plasma of metastatic BC patients to prescribe targeted therapy with alpesilib or elacestrant has already arrived in clinical practice with FDA-approved tests available and is recommended by ASCO. The translation of more liquid biopsy applications into clinical practice is still pending due to a lack of knowledge of the analytes' biology, lack of standards and difficulties in proving clinical utility.

Circulating biomarkers for diagnosis and therapeutic monitoring in bone metastasis

Bone is a frequent site of metastasis for multiple types of solid tumors in organs such as prostate, breast, lung, etc., accounting for significant morbidities and mortalities of afflicted patients. One of the major problems of bone metastasis is lack of biomarkers for early diagnosis and for monitoring therapeutic responses. Medical imaging modalities such as computerized tomography, magnetic resonance imaging, and radioactive isotope-based bone scans are currently standard clinical practices, yet these imaging techniques are limited to detect early lesions or to accurately monitor the metastatic disease progression during standard and/or experimental therapies. Accordingly, development of novel blood biomarkers rationalizes extensive basic research and clinical development. This review article covers the up-to-date information on protein- and cell-based biomarkers of bone metastasis that are currently used in the clinical practices and also are under development.

Clinical trial-identified inflammatory biomarkers in breast and pancreatic cancers

Breast cancer and pancreatic cancer are two common cancer types characterized by high prevalence and high mortality rates, respectively. However, breast cancer has been more well-studied than pancreatic cancer. This narrative review curated inflammation-associated biomarkers from clinical studies that were systematically selected for both breast and pancreatic cancers and discusses some of the common and unique elements between the two endocrine-regulated malignant diseases. Finding common ground between the two cancer types and specifically analyzing breast cancer study results, we hoped to explore potential feasible methods and biomarkers that may be useful also in diagnosing and treating pancreatic cancer. A PubMed MEDLINE search was used to identify articles that were published between 2015-2022 of different kinds of clinical trials that measured immune-modulatory biomarkers and biomarker changes of inflammation defined in diagnosis and treatment of breast cancer and pancreatic cancer patients. A total of 105 papers (pancreatic cancer 23, breast cancer 82) were input into Covidence for the title and abstract screening. The final number of articles included in this review was 73 (pancreatic cancer 19, breast cancer 54). The results showed some of the frequently cited inflammatory biomarkers for breast and pancreatic cancers included IL-6, IL-8, CCL2, CD8+ T cells and VEGF. Regarding unique markers, CA15-3 and TNF-alpha were two of several breast cancer-specific, and CA19 and IL-18 were pancreatic cancer-specific. Moreover, we discussed leptin and MMPs as emerging biomarker targets with potential use for managing pancreatic cancer based on breast cancer studies in the future, based on inflammatory mechanisms. Overall, the similarity in how both types of cancers respond to or result in further disruptive inflammatory signaling, and that point to a list of markers that have been shown useful in diagnosis and/or treatment method response or efficacy in managing breast cancer could potentially provide insights into developing the same or more useful diagnostic and treatment measurement inflammatory biomarkers for pancreatic cancer. More research is needed to investigate the relationship and associated inflammatory markers between the similar immune-associated biological mechanisms that contribute to breast and pancreatic cancer etiology, drive disease progression or that impact treatment response and reflect survival outcomes.

Biological and Clinical Aspects of Metastatic Spinal Tumors

Simple Summary

Spine metastases are a common life-threatening complication of advanced-stage malignancies and often result in poor prognosis. Symptomatic spine metastases develop in the course of about 10% of malignant neoplasms. Therefore, it is essential for contemporary medicine to understand metastatic processes in order to find appropriate, targeted therapeutic options. Our literature review aimed to describe the up-to-date knowledge about the molecular pathways and biomarkers engaged in the spine’s metastatic processes. Moreover, we described current data regarding bone-targeted treatment, the emerging targeted therapies, radiotherapy, and immunotherapy used for the treatment of spine metastases. We hope that knowledge comprehensively presented in our review will contribute to the development of novel drugs targeting specific biomarkers and pathways. The more we learn about the molecular aspects of cancer metastasis, the easier it will be to look for treatment methods that will allow us to precisely kill tumor cells.

Abstract

Spine metastases are a common life-threatening complication of advanced-stage malignancies and often result in poor prognosis. Symptomatic spine metastases develop in the course of about 10% of malignant neoplasms. Therefore, it is essential for contemporary medicine to understand metastatic processes in order to find appropriate, targeted therapeutic options. Thanks to continuous research, there appears more and more detailed knowledge about cancer and metastasis, but these transformations are extremely complicated, e.g., due to the complexity of reactions, the variety of places where they occur, or the participation of both tumor cells and host cells in these transitions. The right target points in tumor metastasis mechanisms are still being researched; that will help us in the proper diagnosis as well as in finding the right treatment. In this literature review, we described the current knowledge about the molecular pathways and biomarkers engaged in metastatic processes involving the spine. We also presented a current bone-targeted treatment for spine metastases and the emerging therapies targeting the discussed molecular mechanisms.

Extensive plasma proteomic profiling revealed receptor activator of nuclear factor kappa-Β ligand (RANKL) as emerging biomarker of nivolumab clinical benefit in patients with metastatic renal cell carcinoma

Background

The advent of immune checkpoint inhibitors (ICIs) have led to a paradigm change in the management of metastatic renal cell carcinoma (mRCC), nevertheless, the benefit of treatment is confined to a limited proportion of patients. Therefore, the identification of predictive biomarkers for response to ICIs represents an unmet clinical need. Here, we performed a large-scale plasma proteomic profile of patients with mRCC, treated with nivolumab, to identify soluble molecules potentially associated with clinical benefit.

Methods

We analyzed the levels of 507 soluble molecules in the pretreatment plasma of 16 patients with mRCC (discovery set) who received nivolumab therapy as a single agent. The ELISA assay was performed to confirm the protein level of candidate biomarkers associated to clinical benefit in 15 patients with mRCC (validation set). Survival curves of complete cohort were estimated by the Kaplan-Meier method and compared with the log-rank test.

Results

Out of 507 screened molecules, 135 factors were selected as expressed above background and 12 of them were significantly overexpressed in patients who did not benefit from treatment (non-responders (NR)) compared with responders (R) group. After multiplicity adjustment, receptor activator of nuclear factor kappa-Β ligand (RANKL) was the only molecule that retained the statistical significance (false discovery rate: 0.023). RANKL overexpression in NR patients was confirmed both in discovery (median NR: 528 pg/mL vs median R: 288 pg/mL, p=0.011) and validation set (median NR: 440 pg/mL vs median R: 253 pg/mL, p<0.001). Considering the complete cohort of patients (discovery+validation set), significantly higher RANKL levels were found in patients who primarily progressed from treatment compared with those who had a partial response (p=0.003) or stable disease (p=0.006). Moreover, patients with low RANKL levels had significant improvements in progression-free survival (median 14.0 months vs 3.4 months, p=0.004) and overall survival (median not reached vs 30.1 months, p=0.003).

Conclusions

Our exploratory study suggests RANKL as a novel independent biomarker of response and survival in patients with mRCC treated with nivolumab.

A micropillar array-based microfluidic chip for label-free separation of circulating tumor cells: The best micropillar geometry?

INTRODUCTION

The information derived from the number and characteristics of circulating tumor cells (CTCs), is crucial to ensure appropriate cancer treatment monitoring. Currently, diverse microfluidic platforms have been developed for isolating CTCs from blood, but it remains a challenge to develop a low-cost, practical, and efficient strategy.

OBJECTIVES

This study aimed to isolate CTCs from the blood of cancer patients via introducing a new and efficient micropillar array-based microfluidic chip (MPA-Chip), as well as providing prognostic information and monitoring the treatment efficacy in cancer patients.

METHODS

We fabricated a microfluidic chip (MPA-Chip) containing arrays of micropillars with different geometries (lozenge, rectangle, circle, and triangle). We conducted numerical simulations to compare velocity and pressure profiles inside the micropillar arrays. Also, we experimentally evaluated the capture efficiency and purity of the geometries using breast and prostate cancer cell lines as well as a blood sample. Moreover, the device's performance was validated on 12 patients with breast cancer (BC) in different states.

RESULTS

The lozenge geometry was selected as the most effective and optimized micropillar design for CTCs isolation, providing high capture efficiency (>85 %), purity (>90 %), and viability (97 %). Furthermore, the lozenge MPA-chip was successfully validated by the detection of CTCs from 12 breast cancer (BC) patients, with non-metastatic (median number of 6 CTCs) and metastatic (median number of 25 CTCs) diseases, showing different prognoses. Also, increasing the chemotherapy period resulted in a decrease in the number of captured CTCs from 23 to 7 for the metastatic patient. The MPA-Chip size was only 0.25 cm² and the throughput of a single chip was 0.5 ml/h, which can be increased by multiple MPA-Chips in parallel.

CONCLUSION

The lozenge MPA-Chip presented a novel micropillar geometry for on-chip CTC isolation, detection, and staining, and in the future, the possibilities can be extended to the culture of the CTCs.

Association of early changes of circulating cancer stem-like cells with survival among patients with metastatic breast cancer

Background:

This study aimed to investigate the role of circulating tumor cells (CTCs) and circulating cancer stem-like cells (cCSCs) before and after one cycle of chemotherapy and assessed the effects of early changes in CTCs and cCSCs on the outcomes of patients with metastatic breast cancer.

Methods:

Patients with stage IV invasive ductal carcinoma of the breast who received first-line chemotherapy between April 2014 and January 2016 were enrolled. CTCs and cCSCs were measured before the first cycle of chemotherapy (baseline) and on day 21, before the second cycle of chemotherapy commenced; a negative selection strategy and flow cytometry protocol were employed.

Results:

CTC and cCSC counts declined in 68.8 and 45.5% of patients, respectively. Declines in CTCs and cCSCs following the first chemotherapy cycle were associated with superior chemotherapy responses, longer progression-free survival (PFS), and longer overall survival (OS). An early decline in cCSCs remained an independent prognostic indicator for OS and PFS in multivariate analysis.

Conclusions:

A cCSC decline after one cycle of chemotherapy for metastatic breast cancer is predictive of a superior chemotherapy response and longer PFS and OS, implying that cCSC dynamic monitoring may be helpful in early prediction of treatment response and prognosis.

3D Culture Modeling of Metastatic Breast Cancer Cells in Additive Manufactured Scaffolds

Cancer biology research is increasingly moving toward innovative in vitro 3D culture models, as conventional and current 2D cell cultures fail to resemble in vivo cancer biology. In the current study, porous 3D scaffolds, designed with two different porosities along with 2D tissue culture polystyrene (TCP) plates were used with a model breast cancer human cell line. The 3D engineered system was evaluated for the optimal seeding method (dynamic versus static), adhesion, and proliferation rate of MDA-MB-231 breast cancer cells. The expression profiles of proliferation-, stemness-, and dormancy-associated cancer markers, namely, ki67, lamin A/C, SOX2, Oct3/4, stanniocalcin 1 (STC1), and stanniocalcin 2 (STC2), were evaluated in the 3D cultured cells and compared to the respective profiles of the cells cultured in the conventional 2D TCP. Our data suggested that static seeding was the optimal seeding method with porosity-dependent efficiency. Moreover, cells cultured in 3D scaffolds displayed a more dormant phenotype in comparison to 2D, which was manifested by the lower proliferation rate, reduced ki67 expression, increased lamin A/C expression, and overexpression of STCs. The possible relationship between the cell affinity to different extracellular matrix (ECM) proteins and the RANK expression levels was also addressed after deriving collagen type I (COL-I) and fibronectin (FN) MDA-MB-231 filial cell lines with enhanced capacity to attach to the respective ECM proteins. The new derivatives exhibited a more mesenchymal like phenotype and higher RANK levels in relation to the parental cells, suggesting a relationship between ECM cell affinity and RANK expression. Therefore, the present 3D cell culture model shows that cancer cells on printed scaffolds can work as better representatives in cancer biology and drug screening related studies.

Clinical significance of circulating tumor cells and cell-free DNA in pediatric rhabdomyosarcoma

Liquid biopsy analysis represents a powerful and noninvasive tool to uncover biomarkers for disseminated disease assessment and longitudinal monitoring of patients. Herein, we explored the value of circulating and disseminated tumor cells (CTC and DTC, respectively) and cell‐free DNA (cfDNA) in pediatric rhabdomyosarcoma (RMS). Peripheral blood and bone marrow samples were analyzed to detect and enumerate CTC and DTC, respectively. We used the epithelial cellular adhesion molecule (EpCAM)‐based CellSearch platform coupled with an automatic device to collect both EpCAM‐positive and EpCAM‐low/negative CTCs. The standard assay was implemented, including the mesenchymal marker desmin. For selected cases, we molecularly profiled primary tumors and liquid biopsy biomarkers using whole‐exome sequencing and droplet digital PCR, respectively. RMS patients with metastatic disease had a significantly higher number of CTCs compared to those with localized disease, whereas DTCs were detected independently of disease presentation. The use of the desmin marker remarkably increased the identification of CTCs and DTCs in RMS samples. Of note, CTC clusters were detected in RMS patients with disseminated disease. Further, cfDNA and CTC molecular features closely reflected the molecular makeup of primary tumors and informed of disease course.

An Immunological Perspective of Circulating Tumor Cells as Diagnostic Biomarkers and Therapeutic Targets

Immune modulation is a hallmark of cancer. Cancer-immune interaction shapes the course of disease progression at every step of tumorigenesis, including metastasis, of which circulating tumor cells (CTCs) are regarded as an indicator. These CTCs are a heterogeneous population of tumor cells that have disseminated from the tumor into circulation. They have been increasingly studied in recent years due to their importance in diagnosis, prognosis, and monitoring of treatment response. Ample evidence demonstrates that CTCs interact with immune cells in circulation, where they must evade immune surveillance or modulate immune response. The interaction between CTCs and the immune system is emerging as a critical point by which CTCs facilitate metastatic progression. Understanding the complex crosstalk between the two may provide a basis for devising new diagnostic and treatment strategies. In this review, we will discuss the current understanding of CTCs and the complex immune-CTC interactions. We also present novel options in clinical interventions, targeting the immune-CTC interfaces, and provide some suggestions on future research directions.

Diagnosis and treatment monitoring in breast cancer: how liquid biopsy can support patient management

Imaging and tissue biopsies represent the current gold standard for breast cancer diagnosis and patient management. However, these practices are time-consuming, expensive and require invasive procedures. Moreover, tissue biopsies do not capture spatial and temporal tumor heterogeneity. Conversely, liquid biopsy, which includes circulating tumor cells, circulating free nucleic acids and extracellular vesicles, is minimally invasive, easy to perform and can be repeated during a patient's follow-up. Increasing evidence also suggests that liquid biopsy can be used to efficiently screen and diagnose tumors at an early stage, and to monitor changes in the tumor molecular profile. In the present review, clinical applications and prospects are discussed.

Predicting Bone Metastasis Using Gene Expression-Based Machine Learning Models

Bone is the most common site of distant metastasis from malignant tumors, with the highest prevalence observed in breast and prostate cancers. Such bone metastases (BM) cause many painful skeletal-related events, such as severe bone pain, pathological fractures, spinal cord compression, and hypercalcemia, with adverse effects on life quality. Many bone-targeting agents developed based on the current understanding of BM onset's molecular mechanisms dull these adverse effects. However, only a few studies investigated potential predictors of high risk for developing BM, despite such knowledge being critical for early interventions to prevent or delay BM. This work proposes a computational network-based pipeline that incorporates a ML/DL component to predict BM development. Based on the proposed pipeline we constructed several machine learning models. The deep neural network (DNN) model exhibited the highest prediction accuracy (AUC of 92.11%) using the top 34 featured genes ranked by betweenness centrality scores. We further used an entirely separate, "external" TCGA dataset to evaluate the robustness of this DNN model and achieved sensitivity of 85%, specificity of 80%, positive predictive value of 78.10%, negative predictive value of 80%, and AUC of 85.78%. The result shows the models' way of learning allowed it to zoom in on the featured genes that provide the added benefit of the model displaying generic capabilities, that is, to predict BM for samples from different primary sites. Furthermore, existing experimental evidence provides confidence that about 50% of the 34 hub genes have BM-related functionality, which suggests that these common genetic markers provide vital insight about BM drivers. These findings may prompt the transformation of such a method into an artificial intelligence (AI) diagnostic tool and direct us towards mechanisms that underlie metastasis to bone events.

The Roadmap of RANKL/RANK Pathway in Cancer

The receptor activator of the nuclear factor-κB ligand (RANKL)/RANK signaling pathway was identified in the late 1990s and is the key mediator of bone remodeling. Targeting RANKL with the antibody denosumab is part of the standard of care for bone loss diseases, including bone metastases (BM). Over the last decade, evidence has implicated RANKL/RANK pathway in hormone and HER2-driven breast carcinogenesis and in the acquisition of molecular and phenotypic traits associated with breast cancer (BCa) aggressiveness and poor prognosis. This marked a new era in the research of the therapeutic use of RANKL inhibition in BCa. RANKL/RANK pathway is also an important immune mediator, with anti-RANKL therapy recently linked to improved response to immunotherapy in melanoma, non-small cell lung cancer (NSCLC), and renal cell carcinoma (RCC). This review summarizes and discusses the pre-clinical and clinical evidence of the relevance of the RANKL/RANK pathway in cancer biology and therapeutics, focusing on bone metastatic disease, BCa onset and progression, and immune modulation.

A fully automated assay to detect the expression of pan-cytokeratins and of EML4-ALK fusion protein in circulating tumour cells (CTCs) predicts outcome of non-small cell lung cancer (NSCLC) patients

Background

In advanced non-small cell lung cancer (NSCLC) a recent meta-analysis confirms circulating tumour cells (CTCs) as an independent prognostic indicator of progression-free survival (PFS) and overall survival (OS). However, further investigations are necessary to predict and dynamically monitor the therapy in NSCLC patients using CTCs. To this aim, we combined the classical standard assay (SA) with an expanded cytokeratins profile (EA) and quantified the expression of EML4-ALK fusion protein in CTCs.

Methods

The CellSearch (CS) platform—first marked in vitro diagnostic use (IVD) from Food and Drug Administration (FDA), and “gold standard” for quantifying CTCs - detects EpCAM and cytokeratins (CKs) 8, 18, and 19. Since NSCLC shows different CKs profile, we customized the SA, to recognize CK 4, 5, 6, 7, 8, 10, 13, 14, 18, and 19 (EA). Using both assays we designed a prospective, multi-center study, primarily aimed to enumerate CTCs in advanced NSCLC. Secondarily, we developed an integration of the EA to quantify the expression of EML4-ALK fusion protein in CTCs, and correlated them with PFS and OS.

Results

EA identified a significantly much more number of CTC-positive patients (115 out of 180) than SA (103 out of 192; Chi-square =4.0179, with 1 degrees of freedom, P=0.04502). Similar to SA, EA levels were still associated with patient’ outcomes. Furthermore, the expression of EML4-ALK on CTCs allowed stratifying NSCLC patients according to a statistically significant difference in PFS.

Conclusions

We proposed here two novel automated tests, to characterize the expression of specific molecules on CTCs. We demonstrated that these integrated assays are robust and actionable in prospective clinical studies, and in the future could allow clinicians to improve both choice and length of treatment in individual NSCLC patient.

Bone metastasis: mechanisms, therapies, and biomarkers

Skeletal metastases are frequent complications of many cancers, causing bone complications (fractures, bone pain, disability) that negatively affect the patient's quality of life. Here, we first discuss the burden of skeletal complications in cancer bone metastasis. We then describe the pathophysiology of bone metastasis. Bone metastasis is a multistage process: long before the development of clinically detectable metastases, circulating tumor cells settle and enter a dormant state in normal vascular and endosteal niches present in the bone marrow, which provide immediate attachment and shelter, and only become active years later as they proliferate and alter the functions of bone-resorbing (osteoclasts) and bone-forming (osteoblasts) cells, promoting skeletal destruction. The molecular mechanisms involved in mediating each of these steps are described, and we also explain how tumor cells interact with a myriad of interconnected cell populations in the bone marrow, including a rich vascular network, immune cells, adipocytes, and nerves. We discuss metabolic programs that tumor cells could engage with to specifically grow in bone. We also describe the progress and future directions of existing bone-targeted agents and report emerging therapies that have arisen from recent advances in our understanding of the pathophysiology of bone metastases. Finally, we discuss the value of bone turnover biomarkers in detection and monitoring of progression and therapeutic effects in patients with bone metastasis.

Current Status of Circulating Tumor Cells, Circulating Tumor DNA, and Exosomes in Breast Cancer Liquid Biopsies

Breast cancer is the most common cancer among women worldwide. Although the five-, ten- and fifteen-year survival rates are good for breast cancer patients diagnosed with early-stage disease, some cancers recur many years after completion of primary therapy. Tumor heterogeneity and clonal evolution may lead to distant metastasis and therapy resistance, which are the main causes of breast cancer-associated deaths. In the clinic today, imaging techniques like mammography and tissue biopsies are used to diagnose breast cancer. Even though these methods are important in primary diagnosis, they have limitations when it comes to longitudinal monitoring of residual disease after treatment, disease progression, therapy responses, and disease recurrence. Over the last few years, there has been an increasing interest in the diagnostic, prognostic, and predictive potential of circulating cancer-derived material acquired through liquid biopsies in breast cancer. Thanks to the development of sensitive devices and platforms, a variety of tumor-derived material, including circulating cancer cells (CTCs), circulating DNA (ctDNA), and biomolecules encapsulated in extracellular vesicles, can now be extracted and analyzed from body fluids. Here we will review the most recent studies on breast cancer, demonstrating the clinical potential and utility of CTCs and ctDNA. We will also review literature illustrating the potential of circulating exosomal RNA and proteins as future biomarkers in breast cancer. Finally, we will discuss some of the advantages and limitations of liquid biopsies and the future perspectives of this field in breast cancer management.

Cancer Stem Cell-Associated Pathways in the Metabolic Reprogramming of Breast Cancer

Metabolic reprogramming of cancer is now considered a hallmark of many malignant tumors, including breast cancer, which remains the most commonly diagnosed cancer in women all over the world. One of the main challenges for the effective treatment of breast cancer emanates from the existence of a subpopulation of tumor-initiating cells, known as cancer stem cells (CSCs). Over the years, several pathways involved in the regulation of CSCs have been identified and characterized. Recent research has also shown that CSCs are capable of adopting a metabolic flexibility to survive under various stressors, contributing to chemo-resistance, metastasis, and disease relapse. This review summarizes the links between the metabolic adaptations of breast cancer cells and CSC-associated pathways. Identification of the drivers capable of the metabolic rewiring in breast cancer cells and CSCs and the signaling pathways contributing to metabolic flexibility may lead to the development of effective therapeutic strategies. This review also covers the role of these metabolic adaptation in conferring drug resistance and metastasis in breast CSCs.

Baseline CD44v6-positive circulating tumor cells to predict first-line treatment failure in patients with metastatic colorectal cancer

CD44v6, the CD44 isoform mostly involved in cancer cell migration and invasion, has been identified as a functional biomarker and therapeutic target in colon cancer stem cells. We here provide evidence that baseline CD44v6-positive CTC predict treatment failure in patients with metastatic colorectal cancer undergoing first-line chemotherapy. We suggest that CD44v6-positive CTC can be used to early detect intrinsic drug resistance in this cancer type.

Pediatric sarcomas display a variable EpCAM expression in a histology-dependent manner

EpCAM is a transmembrane glycoprotein typically overexpressed in cancer of epithelial origin and mainly involved in the epithelial-to–mesenchymal transition (EMT) of tumor cells that spread and disseminate. Strategies for the targeting and capture of EpCAM-expressing tumor cells are showing promise in cancers prone to metastatize, both as diagnostic tools and potential therapies. Sarcomas are among the most aggressive tumors in children, with a common mesenchymal origin that comprises both soft tissue sarcomas (STS) and bone sarcomas. The aim of this study was to assess EpCAM expression in pediatric sarcomas and correlate its expression with disease progression. To do so, we analyzed a set of cell lines and primary tumor tissues from rhabdomyosarcoma (RMS), Ewing sarcoma (ES), synovial sarcoma (SS) and desmoplastic small round cell tumor (DSRCT) STS, or osteosarcoma (OS) bone cancer. We demonstrated that EpCAM was variably expressed in pediatric sarcomas, with DSRCT, a rare, aggressive and almost fatal tumor type, characterized by the highest EpCAM expression levels. Interestingly, although EpCAM expression was lower in RMS tumors, high levels at diagnosis correlated with reduced patients' overall survival (p < 0.05). Indeed, membrane-bound EpCAM was detected in circulating sarcoma tumor cells, revealing its potential to be used as dissemination biomarker in this type of childhood cancers. This reinforces the concept that pediatric sarcomas do express both epithelial and mesenchymal markers and reside in an intermediate condition that most likely contributes to their aggressive phenotype and low survival rate.

Cellular Mechanisms of Circulating Tumor Cells During Breast Cancer Metastasis

Circulating tumor cells (CTCs) are cancer cells that detach from the primary site and travel in the blood stream. A higher number of CTCs increases the risk of breast cancer metastasis, and it is inversely associated with the survival rates of patients with breast cancer. Although the numbers of CTCs are generally low and the majority of CTCs die in circulation, the survival of a few CTCs can seed the development of a tumor at a secondary location. An increasing number of studies demonstrate that CTCs undergo modification in response to the dynamic biophysical environment in the blood due in part to fluid shear stress. Fluid shear stress generates reactive oxygen species (ROS), triggers redox-sensitive cell signaling, and alters the function of intracellular organelles. In particular, the mitochondrion is an important target organelle in determining the metastatic phenotype of CTCs. In healthy cells, mitochondria produce adenosine triphosphate (ATP) via oxidative phosphorylation in the electron transport chain, and during oxidative phosphorylation, they produce physiological levels of ROS. Mitochondria also govern death mechanisms such as apoptosis and mitochondrial permeability transition pore opening to, in order eliminate unwanted or damaged cells. However, in cancer cells, mitochondria are dysregulated, causing aberrant energy metabolism, redox homeostasis, and cell death pathways that may favor cancer invasiveness. In this review, we discuss the influence of fluid shear stress on CTCs with an emphasis on breast cancer pathology, then discuss alterations of cellular mechanisms that may increase the metastatic potentials of CTCs.

Current and Emerging Biomarkers Predicting Bone Metastasis Development

Bone is one of the preferential sites of distant metastases from malignant tumors, with the highest prevalence observed in breast and prostate cancers. Patients with bone metastases (BMs) may experience skeletal-related events, such as severe bone pain, pathological fractures, spinal cord compression, and hypercalcemia, with negative effects on the quality of life. In the last decades, a deeper understanding of the molecular mechanisms underlying the BM onset has been gained, leading to the development of bone-targeting agents. So far, most of the research has been focused on the pathophysiology and treatment of BM, with only relatively few studies investigating potential predictors of risk for BM development. The ability to select such "high-risk" patients could allow early identification of those most likely to benefit from interventions to prevent or delay BM. This review summarizes several evidences for the potential use of specific biomarkers able to predict early the BM development.