Prognostic impact of circulating tumor cells assessed with the CellSearch System™ and AdnaTest Breast™ in metastatic breast cancer patients: the DETECT study

Clinical Application of Different Liquid Biopsy Components in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer, usually occurring in the background of chronic liver disease. HCC lethality rate is in the third highest place in the world. Patients with HCC have concealed early symptoms and possess a high-level of heterogeneity. Once diagnosed, most of the tumors are in advanced stages and have a poor prognosis. The sensitivity and specificity of existing detection modalities and protocols are suboptimal. HCC calls for more sophisticated and individualized therapeutic regimens. Liquid biopsy is non-invasive, repeatable, unaffected by location, and can be monitored dynamically. It has emerged as a useable aid in achieving precision malignant tumor treatment. Circulating tumor cells (CTCs), circulating nucleic acids, exosomes and tumor-educated platelets are the commonest components of a liquid biopsy. It possesses the theoretical ability to conquer the high heterogeneity and the difficulty of early detection for HCC patients. In this review, we summarize the common enrichment techniques and the clinical applications in HCC for different liquid biopsy components. Tumor recurrence after HCC-related liver transplantation is more insidious and difficult to treat. The clinical use of liquid biopsy in HCC-related liver transplantation is also summarized in this review.

Liquid biopsy for gastric cancer: Techniques, applications, and future directions

After the study of circulating tumor cells in blood through liquid biopsy (LB), this technique has evolved to encompass the analysis of multiple materials originating from the tumor, such as nucleic acids, extracellular vesicles, tumor-educated platelets, and other metabolites. Additionally, research has extended to include the examination of samples other than blood or plasma, such as saliva, gastric juice, urine, or stool. LB techniques are diverse, intricate, and variable. They must be highly sensitive, and pre-analytical, patient, and tumor-related factors significantly influence the detection threshold, diagnostic method selection, and potential results. Consequently, the implementation of LB in clinical practice still faces several challenges. The potential applications of LB range from early cancer detection to guiding targeted therapy or immunotherapy in both early and advanced cancer cases, monitoring treatment response, early identification of relapses, or assessing patient risk. On the other hand, gastric cancer (GC) is a disease often diagnosed at advanced stages. Despite recent advances in molecular understanding, the currently available treatment options have not substantially improved the prognosis for many of these patients. The application of LB in GC could be highly valuable as a non-invasive method for early diagnosis and for enhancing the management and outcomes of these patients. In this comprehensive review, from a pathologist's perspective, we provide an overview of the main options available in LB, delve into the fundamental principles of the most studied techniques, explore the potential utility of LB application in the context of GC, and address the obstacles that need to be overcome in the future to make this innovative technique a game-changer in cancer diagnosis and treatment within clinical practice.

Targeting circulating tumor cells to prevent metastases

Circulating tumor cells (CTCs) are cancer cells that detach from the primary tumor, enter the bloodstream or body fluids, and spread to other body parts, leading to metastasis. Their presence and characteristics have been linked to cancer progression and poor prognosis in different types of cancer. Analyzing CTCs can offer valuable information about tumors' genetic and molecular diversity, which is crucial for personalized therapy. Epithelial-mesenchymal transition (EMT) and the reverse process, mesenchymal-epithelial transition (MET), play a significant role in generating and disseminating CTCs. Certain proteins, such as EpCAM, vimentin, CD44, and TGM2, are vital in regulating EMT and MET and could be potential targets for therapies to prevent metastasis and serve as detection markers. Several devices, methods, and protocols have been developed for detecting CTCs with various applications. CTCs interact with different components of the tumor microenvironment. The interactions between CTCs and tumor-associated macrophages promote local inflammation and allow the cancer cells to evade the immune system, facilitating their attachment and invasion of distant metastatic sites. Consequently, targeting and eliminating CTCs hold promise in preventing metastasis and improving patient outcomes. Various approaches are being explored to reduce the volume of CTCs. By investigating and discussing targeted therapies, new insights can be gained into their potential effectiveness in inhibiting the spread of CTCs and thereby reducing metastasis. The development of such treatments offers great potential for enhancing patient outcomes and halting disease progression.

Clinical application of circulating tumor cells

This narrative review aims to provide a comprehensive overview of the current state of circulating tumor cell (CTC) analysis and its clinical significance in patients with epithelial cancers. The review explores the advancements in CTC detection methods, their clinical applications, and the challenges that lie ahead. By examining the important research findings in this field, this review offers the reader a solid foundation to understand the evolving landscape of CTC analysis and its potential implications for clinical practice. The comprehensive analysis of CTCs provides valuable insights into tumor biology, treatment response, minimal residual disease detection, and prognostic evaluation. Furthermore, the review highlights the potential of CTCs as a non-invasive biomarker for personalized medicine and the monitoring of treatment efficacy. Despite the progress made in CTC research, several challenges such as standardization, validation, and integration into routine clinical practice remain. The review concludes by discussing future directions and the potential impact of CTC analysis on improving patient outcomes and guiding therapeutic decision-making in epithelial cancers.

Monitoring with circulating tumor cells in the perioperative setting of patients with surgically treated stages I-IIIA NSCLC

Background

Surgery is regarded as the treatment's cornerstone for early stage and locally advanced non-small cell lung cancer (NSCLC) whenever the tumor is considered resectable. Liquid biopsy is one of the most promising research areas in oncology in the last 10 years, providing a useful non-invasive tool to detect and monitor cancer. The prognostic value of circulating tumor cells (CTCs) has been studied in different cancer types and had been related with a higher risk of relapse and worse prognosis. The aim of this study is to evaluate the prognostic value of CTC detection in patients with stage I-IIIA NSCLC treated with surgery.

Methods

We conducted a prospective, single-center study of 180 consecutive patients with resected and pathological confirmed stage I to IIIA (TNM AJCC/UICC 8th edition) NSCLC. Patients' blood samples were processed and CTCs were characterized before and after the surgery. A cohort of patients had CTC determination after chemotherapy and surgery. Cut-off points were established in 1 and 5 CTCs for statistical analysis.

Results

A proportion of 76.7% had at least 1 CTC before the surgery, and 30.6% had 5 or more, while 55.9% had at least 1 CTC after surgery, and 8.3% had 5 or more. We found no correlation between preoperative CTC detection for a cut-off of 5 with neither overall survival (OS) [hazard ratio (HR): 0.99, P=0.887], disease-free survival (DFS) (HR: 0.95, P=0.39) nor relapse (32.7% vs. 28.8%, P=0.596). We also did not find a correlation between postoperative CTCs detection for a cut-off of 5 with either OS (HR: 1.01, P=0.808), DFS (HR: 0.95, P=0.952) or relapse (26.7% vs. 29.5%, P=0.83). The mean change in the number of CTCs over time between preoperative and postoperative samples was 2.13, with a standard deviation of 6.78.

Conclusions

Despite the large cohort of patients included in this study, CTC monitoring in the perioperative setting was not correlated with relapse, DFS or OS in our study, and therefore cannot be recommended as a reliable biomarker for minimal residual disease (MRD) after surgery.

Preclinical models to study patient-derived circulating tumor cells and metastasis

Circulating tumor cells (CTCs) that are detached from the tumor can be precursors of metastasis. The majority of studies focus on enumeration of CTCs from patient blood to predict recurrence and therapy outcomes. Very few studies have managed to expand CTCs to investigate their functional dynamics with respect to genetic changes, tumorigenic potential, and response to drug treatment. A growing amount of evidence based on successful CTC expansion has revealed novel therapeutic targets that are associated with the process of metastasis. In this review, we summarize the successes, challenges, and limitations that collectively contribute to the better understanding of metastasis using patient-derived CTCs as blood-borne seeds of metastasis. The roadblocks and future avenues to move CTC-based scientific discoveries forward are also discussed.

Comparison of RNA Marker Panels for Circulating Tumor Cells and Evaluation of Their Prognostic Relevance in Breast Cancer

Liquid biopsy is a promising tool for therapy monitoring of cancer patients, but a need for further research in this field exists in order to improve sensitivity, specificity, standardization and minimize costs. In our present study, we evaluated two panels of transcripts related with the presence of circulating tumor cells (CTCs) (Panel 1: CK19, EpCAM, SCGB2A2 and Panel 2: EMP2, SLC6A8, HJURP, MAL2, PPIC and CCNE2) in two cohorts of breast cancer patients (metastatic and early). A blood cell fraction possibly containing CTCs was isolated with density gradient centrifugation, followed by RNA isolation and qPCR using TaqMan^® or RT-qPCR using hybridization probes. The positivity rates of the investigated panels were similar, albeit higher in metastatic (69.4% Panel 1, 75.0% Panel 2; total 86.1%) compared to early (18.9% Panel 1, 23.3% Panel 2; total 31.1%) breast cancer patients. CK19, SCGB2A2, EMP2, HJURP, MAL2, and CCNE2 individually correlated with shorter overall survival in the metastatic patient cohort. The findings highlight the additional value of Panel 2 markers, which are in contrast to CK19 and EpCAM not solely linked to an epithelial phenotype.

Biology, vulnerabilities and clinical applications of circulating tumour cells

In recent years, exceptional technological advances have enabled the identification and interrogation of rare circulating tumour cells (CTCs) from blood samples of patients, leading to new fields of research and fostering the promise for paradigm-changing, liquid biopsy-based clinical applications. Analysis of CTCs has revealed distinct biological phenotypes, including the presence of CTC clusters and the interaction between CTCs and immune or stromal cells, impacting metastasis formation and providing new insights into cancer vulnerabilities. Here we review the progress made in understanding biological features of CTCs and provide insight into exploiting these developments to design future clinical tools for improving the diagnosis and treatment of cancer.

Impact of endoscopic metallic stent placement and emergency surgery on detection of viable circulating tumor cells for acute malignant left-sided colonic obstruction

BACKGROUND

Self-expanding metal stents (SEMS) served as a bridge to surgery (BTS). However, this method may be associated with worse long-term prognosis and relapse of CRC patients. Therefore, we attempted to clarify this in the angle of circulating tumor cells (CTCs).

METHODS

A multicenter study was performed from March 2018 to January 2021. Thirty-two colorectal cancer patients with obstruction were selected, of which 21 patients were performed SEMS as a BTS while 11 patients were performed emergency surgery. Bloods samples were collected in two groups of patients for further detecting CTCs. In the SEMS group, the samples were collected before and after stent insert and after radical surgery performed. In the ES group, the samples were collected before stent insert and after emergency surgery performed.

RESULTS

The number of CTCs did not show statistically significant differences before and after stent placement (34.90 vs 38.33, p=0.90), neither between the SEMS group and ES group in initial CTC levels (34.90 vs 58.09, p=0.394). No significant differences (38.33 vs 58.09, p=0.632) were observed after stent insert in the SMES group and the initial CTC levels in the ES group. Moreover, no major differences (24.17 vs 42.27, p=0.225) were observed after radical operation performed in both groups.

CONCLUSION

The treatment of SEMS does not cause an increase in the number of CTC after stent insertion. Furthermore, there are may be other factors besides CTC to cause these poorer oncologic outcomes after SEMS placement.

Detection of circulating tumor cells: opportunities and challenges

Circulating tumor cells (CTCs) are cells that shed from a primary tumor and travel through the bloodstream. Studying the functional and molecular characteristics of CTCs may provide in-depth knowledge regarding highly lethal tumor diseases. Researchers are working to design devices and develop analytical methods that can capture and detect CTCs in whole blood from cancer patients with improved sensitivity and specificity. Techniques using whole blood samples utilize physical prosperity, immunoaffinity or a combination of the above methods and positive and negative enrichment during separation. Further analysis of CTCs is helpful in cancer monitoring, efficacy evaluation and designing of targeted cancer treatment methods. Although many advances have been achieved in the detection and molecular characterization of CTCs, several challenges still exist that limit the current use of this burgeoning diagnostic approach. In this review, a brief summary of the biological characterization of CTCs is presented. We focus on the current existing CTC detection methods and the potential clinical implications and challenges of CTCs. We also put forward our own views regarding the future development direction of CTCs.

Detection of Circulating Tumor Cells in Cerebrospinal Fluid of Patients with Suspected Breast Cancer Leptomeningeal Metastases: A Prospective Study

BACKGROUND

The diagnosis of breast cancer (BC)-related leptomeningeal metastases (LM) relies on the detection of tumor cells in cerebrospinal fluid (CSF) using conventional cytology (gold standard). However, the sensitivity of this technique is low. Our goal was to evaluate whether circulating tumor cell (CTC) detection in CSF using the CellSearch® system could be used for LM diagnosis.

METHODS

This prospective, monocentric study included adult patients with suspected BC-related LM. The clinical sensitivity and specificity of CTC detection in CSF for LM diagnosis were calculated relative to conventional CSF cytology.

RESULTS

Forty-nine eligible patients were included and 40 were evaluable (CTC detection technical failure: n = 8, eligibility criteria failure: n = 1). Cytology was positive in 18/40 patients. CTCs were detected in these 18 patients (median: 5824 CTC, range: 93 to 45052) and in 5/22 patients with negative cytology (median: 2 CTC, range: 1 to 44). The detection of ≥1 CSF CTC was associated with a clinical sensitivity of 100% (95% CI, 82.4-100) and a specificity of 77.3% (95% CI, 64.3-90.3) for LM diagnosis. HER2+ CTCs were detected in the CSF of 40.6% of patients with HER2- BC (median: 500 CTC, range: 13 to 28 320).

CONCLUSIONS

The clinical sensitivity of CTC detection in CSF with the CellSearch® system for LM diagnosis is higher than that of CSF cytology. CTC detection in patients with negative cytology, however, must be further investigated. The finding of HER2+ CTCs in patients with HER2- BC suggests that the HER2 status of LM should be evaluated to increase the treatment opportunities for these patients.

Detection and Characterization of Estrogen Receptor α Expression of Circulating Tumor Cells as a Prognostic Marker

CTCs have increasingly been used as a liquid biopsy analyte to obtain real-time information on the tumor through minimally invasive blood analyses. CTCs allow for the identification of proteins relevant for targeted therapies. Here, we evaluated the expression of estrogen receptors (ER) in CTCs of patients with metastatic breast cancer. From sixty metastatic breast cancer patients who had ER-positive primary tumors (range of 1−70% immunostaining) at initial cancer diagnosis, 109 longitudinal blood samples were prospectively collected and analyzed using the CellSearch System in combination with the ERα monoclonal murine ER-119.3 antibody. Prolonged cell permeabilization was found to be required for proper staining of nuclear ER in vitro. Thirty-one cases were found to be CTC-positive; an increased number of CTCs during endocrine and chemotherapy was correlated with disease progression, whereas a decrease or stable amount of CTC number (<5) during treatment was correlated with a better clinical outcome. Survival analyses further indicate a positive association of CTC-status with progression-free survival (HR, 66.17; 95%CI, 3.66−195.96; p = 0.0045) and overall survival (HR, 6.21; 95%CI, 2.66−14.47; p < 0.0001). Only one-third of CTC-positive breast cancer patients, who were initially diagnosed with ER-positive primary tumors, harbored ER-positive CTCs at the time of metastasis, and even in those patients, both ER-positive and ER-negative CTCs were found. CTC-positivity was correlated with a shorter relapse-free survival. Remarkably, ER-negative CTCs were frequent despite initial ER-positive status of the primary tumor, suggesting a switch of ER phenotype or selection of minor ER-negative clones as a potential mechanism of escape from ER-targeting therapy.

Functional analysis of circulating tumour cells: the KEY to understand the biology of the metastatic cascade

Metastasis formation is the main cause of cancer-related death in patients with solid tumours. At the beginning of this process, cancer cells escape from the primary tumour to the blood circulation where they become circulating tumour cells (CTCs). Only a small subgroup of CTCs will survive during the harsh journey in the blood and colonise distant sites. The in-depth analysis of these metastasis-competent CTCs is very challenging because of their extremely low concentration in peripheral blood. So far, only few groups managed to expand in vitro and in vivo CTCs to be used as models for large-scale descriptive and functional analyses of CTCs. These models have shown already the high variability and complexity of the metastatic cascade in patients with cancer, and open a new avenue for the development of new diagnostic and therapeutic approaches.

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

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

Circulating tumour cells in the -omics era: how far are we from achieving the 'singularity'?

Over the past decade, cancer diagnosis has expanded to include liquid biopsies in addition to tissue biopsies. Liquid biopsies can result in earlier and more accurate diagnosis and more effective monitoring of disease progression than tissue biopsies as samples can be collected frequently. Because of these advantages, liquid biopsies are now used extensively in clinical care. Liquid biopsy samples are analysed for circulating tumour cells (CTCs), cell-free DNA, RNA, proteins and exosomes. CTCs originate from the tumour, play crucial roles in metastasis and carry information on tumour heterogeneity. Multiple single-cell omics approaches allow the characterisation of the molecular makeup of CTCs. It has become evident that CTCs are robust biomarkers for predicting therapy response, clinical development of metastasis and disease progression. This review describes CTC biology, molecular heterogeneity within CTCs and the involvement of EMT in CTC dynamics. In addition, we describe the single-cell multi-omics technologies that have provided insights into the molecular features within therapy-resistant and metastasis-prone CTC populations. Functional studies coupled with integrated multi-omics analyses have the potential to identify therapies that can intervene the functions of CTCs.

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.

Prognostic relevance of the HER2 status of circulating tumor cells in metastatic breast cancer patients screened for participation in the DETECT study program

BACKGROUND

Circulating tumor cells (CTCs) have been reported to predict clinical outcome in metastatic breast cancer (MBC). Biology of CTCs may differ from that of the primary tumor and HER2-positive CTCs are found in some patients with HER2-negative tumors.

PATIENTS AND METHODS

Patients with HER2-negative MBC were screened for participation in DETECT III and IV trials before the initiation of a new line of therapy. Blood samples were analyzed using CELLSEARCH. CTCs were labeled with an anti-HER2 antibody and classified according to staining intensity (negative, weak, moderate, or strong staining).

RESULTS

Screening blood samples were analyzed in 1933 patients with HER2-negative MBC. As many as 1217 out of the 1933 screened patients (63.0%) had ≥1 CTC per 7.5 ml blood; ≥5 CTCs were detected in 735 patients (38.0%; range 1-35 078 CTCs, median 8 CTCs). HER2 status of CTCs was assessed in 1159 CTC-positive patients; ≥1 CTC with strong HER2 staining was found in 174 (15.0%) patients. The proportion of CTCs with strong HER2 staining among all CTCs of an individual patient ranged between 0.06% and 100% (mean 15.8%). Patients with estrogen receptor (ER)- and progesterone receptor (PR)-positive tumors were more likely to harbor ≥1 CTC with strong HER2 staining. CTC status was significantly associated with overall survival (OS). Detection of ≥1 CTC with strong HER2 staining was associated with shorter OS [9.7 (7.1-12.3) versus 16.5 (14.9-18.1) months in patients with CTCs with negative-to-moderate HER2 staining only, P = 0.013]. In multivariate analysis, age, ER status, PR status, Eastern Cooperative Oncology Group performance status, therapy line, and CTC status independently predicted OS.

CONCLUSION

CTC detection in patients with HER2-negative disease is a strong prognostic factor. Presence of ≥1 CTC with strong HER2 staining was associated with shorter OS, supporting a biological role of HER2 expression on CTCs.

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

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

Circulating Tumor Cells: Technologies and Their Clinical Potential in Cancer Metastasis

Circulating tumor cells (CTCs) are single cells or clusters of cells within the circulatory system of a cancer patient. While most CTCs will perish, a small proportion will proceed to colonize the metastatic niche. The clinical importance of CTCs was reaffirmed by the 2008 FDA approval of CellSearch^®, a platform that could extract EpCAM-positive, CD45-negative cells from whole blood samples. Many further studies have demonstrated the presence of CTCs to stratify patients based on overall and progression-free survival, among other clinical indices. Given their unique role in metastasis, CTCs could also offer a glimpse into the genetic drivers of metastasis. Investigation of CTCs has already led to groundbreaking discoveries such as receptor switching between primary tumors and metastatic nodules in breast cancer, which could greatly affect disease management, as well as CTC-immune cell interactions that enhance colonization. In this review, we will highlight the growing variety of isolation techniques for investigating CTCs. Next, we will provide clinically relevant context for CTCs, discussing key clinical trials involving CTCs. Finally, we will provide insight into the future of CTC studies and some questions that CTCs are primed to answer.

Prognostic Factors in Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative (HR+/HER2-) Advanced Breast Cancer: A Systematic Literature Review

Purpose

Advanced breast cancer is a heterogeneous disease with several well-defined subtypes, among which, hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2–) is most prevalent. Determination of HR and HER2 status influences prognosis and, thus, disease management. Although literature on these prognostic factors exist, especially in the early breast cancer setting, it remains unclear to what extent these factors can guide clinical decision-making in the advanced disease setting. Therefore, we sought to identify the strength and consistency of evidence for prognostic factors in patients with HR+/HER2– advanced breast cancer.

Methods

A systematic literature review (SLR) of the major electronic databases was conducted in November 2018 for primary research studies published since 2010. Endpoints of interest were tumor response, progression-free survival (PFS), overall survival (OS), and breast cancer-specific survival (BCSS).

Results

Seventy-nine studies were included wherein all patients were diagnosed with advanced breast cancer and ≥50% of the population were HR+/HER2–. OS was the most commonly assessed endpoint (n=67) followed by PFS (n=33), BCSS (n=5) and tumor response (n=3). The prognostic factors with strongest evidence of association with worse OS were negative progesterone receptor status, higher tumor grade, higher circulating tumor cell (CTC) count and higher Ki67 level, number of metastatic sites (eg multiple vs single) and sites of metastases (eg presence of liver metastases vs absence), shorter time to recurrence or progression to advanced breast cancer, poor performance status, prior therapy attributes in the early or metastatic setting (type of therapy, treatment line, response of prior therapy), and race (black vs white). The prognostic factors that had strongest evidence of association with PFS included CTC count, number and sites of metastases, and absence of prior therapy or higher lines of therapy in the early or metastatic setting. The directionality of association was consistent for all prognostic factors except between lymph node and OS, and de novo metastatic breast cancer and PFS.

Conclusion

Multiple disease, treatment, and patient-related prognostic factors impact survival, particularly OS, in patients with HR+/HER2– advanced breast cancer. Treatment outcomes can vary considerably due to these factors. Understanding poorer prognostic factors for patients can result in improved clinical decision-making.

Liquid Biopsy in Breast Cancer: A Focused Review

CONTEXT.—

The role of liquid biopsy in cancer management has been gaining increased prominence in the past decade, with well-defined clinical applications now being established in lung cancer. Recently, the US Food and Drug Administration also approved the Therascreen PIK3CA RGQ polymerase chain reaction assay as a companion diagnostic assay to detect PIK3CA mutations in breast cancer for both tissue and liquid biopsies, bringing the role of liquid biopsy in breast cancer management to the fore. Its utility in other aspects of breast cancer, however, is yet to be clearly defined.

OBJECTIVE.—

To review the studies that looked at liquid biopsies in breast cancer and examine their potential for clinical application in the areas of early diagnosis, prognostication, monitoring disease response, detecting minimal residual disease, and predicting risk of progression or relapse. We focus mainly on circulating tumor cells and circulating tumor DNA.

DATA SOURCES.—

Peer-reviewed articles in PubMed.

CONCLUSIONS.—

Liquid biopsies in breast cancers have yielded promising results, especially in the areas of monitoring treatment response and predicting disease progression or relapse. With further study, and hopefully coupled with continued improvements in technologies that isolate tumor-derived materials, liquid biopsies may go on to play a greater role in the breast cancer clinic.

Circulating tumor cells as prognostic biomarkers in breast cancer: current status and future prospects

Introduction : Despite advances in diagnostic and therapeutic techniques breast cancer is still associated with significant morbidity and mortality. CTCs play a crucial role in the metastatic process, which is the main cause of death in BC patients.Areas covered : This review discusses the prognostic and predictive value of CTCs and their prospective in management of BC patients.Expert opinion : The analysis of CTCs through improved technologies offers a new insight into the metastatic cascade. Assessment of the number and molecular profile of CTCs holds great promises for disease monitoring and therapeutic decisions. However, more research is needed until they can be used in therapeutic decisions in clinical practice.

Highly Correlated Recurrence Prognosis in Patients with Metastatic Colorectal Cancer by Synergistic Consideration of Circulating Tumor Cells/Microemboli and Tumor Markers CEA/CA19-9

Circulation tumor cells (CTCs) play an important role in metastasis and highly correlate with cancer progression; thus, CTCs could be considered as a powerful diagnosis tool. Our previous studies showed that the number of CTCs could be utilized for recurrence prediction in colorectal cancer (CRC); however, the odds ratio was still lower than five. To improve prognosis in CRC patients, we analyzed CTC clusters/microemboli, CTC numbers, and carcinoembryonic antigen (CEA)/carbohydrate antigen 19-9 (CA19-9) levels using a self-assembled cell array (SACA) chip system for recurrence prediction. In CRC patients, the presence of CTC clusters/microemboli may have higher correlation in metastasis when compared to the high number of CTCs. Additionally, when both the number of CTCs and serum CEA levels are high, very high odds ratios of 24.4 and 17.1 are observed in patients at all stages and stage III of CRC, respectively. The high number of CTCs and CTC clusters/microemboli simultaneously suggests the high chance of relapse (odds ratio 8.4). Overall, the characteristic of CTC clusters/microemboli, CEA level, and CTC number have a clinical potential to enhance CRC prognosis.

Heterogeneous Circulating Tumor Cells in Sarcoma: Implication for Clinical Practice

Simple Summary

The present review is aimed to discuss the relevance of assaying for the presence and isolation of circulating tumor cells (CTCs) in patients with sarcoma. Just a few studies have been performed to detect and enumerate viable CTCs in sarcoma and a majority of them still represent proof-of-concept studies, while more frequently tumor cells have been detected in the circulation by using the PCR-based method. Nevertheless, recent advances in technologies allowed detection of epithelial–mesenchymal transitioned CTCs from patients with mesenchymal malignancies, despite results being mostly preliminary. The possibility to identify CTCs holds a great promise for both applications of liquid biopsy in sarcoma for precision medicine, and for research purposes to pinpoint the mechanism of the metastatic process through the characterization of tumor mesenchymal cells. Coherently, clinical trials in sarcoma have been designed accordingly to detect CTCs, for diagnosis, identification of novel therapeutic targets and resistance mechanisms of systemic therapies, and patient stratification.

Abstract

Bone and soft tissue sarcomas (STSs) represent a group of heterogeneous rare malignant tumors of mesenchymal origin, with a poor prognosis. Due to their low incidence, only a few studies have been reported addressing circulating tumor cells (CTCs) in sarcoma, despite the well-documented relevance for applications of liquid biopsy in precision medicine. In the present review, the most recent data relative to the detection and isolation of viable and intact CTCs in these tumors will be reviewed, and the heterogeneity in CTCs will be discussed. The relevance of epithelial–mesenchymal plasticity and stemness in defining the phenotypic and functional properties of these rare cells in sarcoma will be highlighted. Of note, the existence of dynamic epithelial–mesenchymal transition (EMT)-related processes in sarcoma tumors has only recently been related to their clinical aggressiveness. Also, the presence of epithelial cell adhesion molecule (EpCAM)-positive CTC in sarcoma has been weakly correlated with poor outcome and disease progression, thus proving the existence of both epithelial and mesenchymal CTC in sarcoma. The advancement in technologies for capturing and enumerating all diverse CTCs phenotype originating from these mesenchymal tumors are presented, and results provide a promising basis for clinical application of CTC detection in sarcoma.

Label-free discrimination and selection of cancer cells from blood during flow using holography-induced dielectrophoresis

We present a method for label-free imaging and sorting of cancer cells in blood, which is based on a dielectrophoretic microfluidic chip and label-free interferometric phase microscopy. The chip used for imaging has been embedded with dielectrophoretic electrodes, and therefore it can be used to sort the cells based on the decisions obtained during the cell flow by the label-free quantitative imaging method. Hence, we obtained a real-time, automatic, label-free imaging flow cytometry with the ability to sort the cells during flow. To validate our model, we combined into the label-free imaging interferometer a fluorescence imaging channel that indicated the correctness of the label-free sorting. We have achieved above 98% classification success and 69% sorting accuracy at flow rates of 4 to 7 μL hr^-1 . In the future, this method is expected to help in label-free sorting of circulating tumor cells in blood following an initial state-of-the-art cell enrichment.

Non-Invasive Biomarkers for Early Detection of Breast Cancer

Breast cancer is the most common cancer in women worldwide. Accurate early diagnosis of breast cancer is critical in the management of the disease. Although mammogram screening has been widely used for breast cancer screening, high false-positive and false-negative rates and radiation from mammography have always been a concern. Over the last 20 years, the emergence of "omics" strategies has resulted in significant advances in the search for non-invasive biomarkers for breast cancer diagnosis at an early stage. Circulating carcinoma antigens, circulating tumor cells, circulating cell-free tumor nucleic acids (DNA or RNA), circulating microRNAs, and circulating extracellular vesicles in the peripheral blood, nipple aspirate fluid, sweat, urine, and tears, as well as volatile organic compounds in the breath, have emerged as potential non-invasive diagnostic biomarkers to supplement current clinical approaches to earlier detection of breast cancer. In this review, we summarize the current progress of research in these areas.

A Direct Comparison between the Lateral Magnetophoretic Microseparator and AdnaTest for Isolating Prostate Circulating Tumor Cells

Circulating tumor cells (CTCs) are important biomarkers for the diagnosis, prognosis, and treatment of cancer. However, because of their extreme rarity, a more precise technique for isolating CTCs is required to gain deeper insight into the characteristics of cancer. This study compares the performance of a lateral magnetophoretic microseparator (“CTC-μChip”), as a representative microfluidic device, and AdnaTest ProstateCancer (Qiagen), as a commercially available specialized method, for isolating CTCs from the blood of patients with prostate cancer. The enumeration and genetic analysis results of CTCs isolated via the two methods were compared under identical conditions. In the CTC enumeration experiment, the number of CTCs isolated by the CTC-μChip averaged 17.67 CTCs/mL, compared to 1.56 CTCs/mL by the AdnaTest. The number of contaminating white blood cells (WBCs) and the CTC purity with the CTC-μChip averaged 772.22 WBCs/mL and 3.91%, respectively, whereas those with the AdnaTest averaged 67.34 WBCs/mL and 1.98%, respectively. Through genetic analysis, using a cancer-specific gene panel (AR (androgen receptor), AR-V7 (A\androgen receptor variant-7), PSMA (prostate specific membrane antigen), KRT19 (cytokeratin-19), CD45 (PTPRC, Protein tyrosine phosphatase, receptor type, C)) with reverse transcription droplet digital PCR, three genes (AR, AR-V7, and PSMA) were more highly expressed in cells isolated by the CTC-μChip, while KRT19 and CD45 were similarly detected using both methods. Consequently, this study showed that the CTC-μChip can be used to isolate CTCs more reliably than AdnaTest ProstateCancer, as a specialized method for gene analysis of prostate CTCs, as well as more sensitively obtain cancer-associated gene expressions.

The Role of Proteoglycans in Cancer Metastasis and Circulating Tumor Cell Analysis

Circulating tumor cells (CTCs) are accessible by liquid biopsies via an easy blood draw. They represent not only the primary tumor site, but also potential metastatic lesions, and could thus be an attractive supplement for cancer diagnostics. However, the analysis of rare CTCs in billions of normal blood cells is still technically challenging and novel specific CTC markers are needed. The formation of metastasis is a complex process supported by numerous molecular alterations, and thus novel CTC markers might be found by focusing on this process. One example of this is specific changes in the cancer cell glycocalyx, which is a network on the cell surface composed of carbohydrate structures. Proteoglycans are important glycocalyx components and consist of a protein core and covalently attached long glycosaminoglycan chains. A few CTC assays have already utilized proteoglycans for both enrichment and analysis of CTCs. Nonetheless, the biological function of proteoglycans on clinical CTCs has not been studied in detail so far. Therefore, the present review describes proteoglycan functions during the metastatic cascade to highlight their importance to CTCs. We also outline current approaches for CTC assays based on targeting proteoglycans by their protein cores or their glycosaminoglycan chains. Lastly, we briefly discuss important technical aspects, which should be considered for studying proteoglycans.

Circulating Tumor Cells: State-of-the-art Update on Technologies and Clinical Applications

PURPOSE OF REVIEW

Circulating tumor cells represent rare events in the peripheral blood of patients with cancer that can provide insight into tumor biology. CTC enumeration, isolation, and analysis represent liquid biopsy approaches whose role in the management of patients with cancer continues to evolve in the era of precision medicine. This review presents an overview of technologies central to studying CTCs.

RECENT FINDINGS

Technologies for CTC isolation can be divided into two categories: label-dependent and label-independent. Label-dependent techniques utilize biological properties such as cell surface proteins, while label-independent techniques utilize distinctive physical properties such as cell size, density, and plasticity. Advances in microfluidics designs as well as hybrid combinations of label-dependent and label-independent techniques have resulted in unprecedented improvements in CTC isolation, permitting not only the detection and enumeration of these rare events but also providing the means for studying them and exploring them as a new dimension of cancer biomarkers. With advances in tools for isolating and studying CTCs in hand, questions regarding the clinical utility of CTC enumeration in peripheral blood, detection of CTC-associated biomarkers, and analysis of dynamic changes in CTCs during the course of cancer therapy represent exciting new opportunities for cancer research.

Circulating Tumor Cell Detection Technologies and Clinical Utility: Challenges and Opportunities

The potential clinical utility of circulating tumor cells (CTCs) in the diagnosis and management of cancer has drawn a lot of attention in the past 10 years. CTCs disseminate from tumors into the bloodstream and are believed to carry vital information about tumor onset, progression, and metastasis. In addition, CTCs reflect different biological aspects of the primary tumor they originate from, mainly in their genetic and protein expression. Moreover, emerging evidence indicates that CTC liquid biopsies can be extended beyond prognostication to pharmacodynamic and predictive biomarkers in cancer patient management. A key challenge in harnessing the clinical potential and utility of CTCs is enumerating and isolating these rare heterogeneous cells from a blood sample while allowing downstream CTC analysis. That being said, there have been serious doubts regarding the potential value of CTCs as clinical biomarkers for cancer due to the low number of promising outcomes in the published results. This review aims to present an overview of the current preclinical CTC detection technologies and the advantages and limitations of each sensing platform, while surveying and analyzing the published evidence of the clinical utility of CTCs.

Cell surface vimentin-positive circulating tumor cell-based relapse prediction in a long-term longitudinal study of postremission neuroblastoma patients

Neuroblastoma (NB) is a deadly childhood disease that carries a 50% chance of relapse for anyone in remission and similar level of 5-year survival. We investigated the value of our proprietary approach-cell surface vimentin (CSV) positive circulating tumor cells (CTC) to monitor treatment response and predict relapse in NB patients under remission in a Phase II long-term preventative clinical trial. We longitudinally analyzed peripheral blood samples from 93 patients for 27 cycles (~25 months) and discovered that the presence of CSV⁺ CTCs in the first two sequential samples (baseline, cycle 4 [month 3-4]) was a significant indicator of earlier relapse. We observed strong correlation between relapse-free survival (RFS) and lack of CSV⁺ CTCs in first 4 cycles of therapy (95%). There was sensitivity reaching 100% in predicting RFS in patients who had neither CSV⁺ CTCs nor MycN amplification. Of note, the low number of CSV⁺ CTCs seems equivalent to low tumor load because the prevention therapy difluoromethylornithine yields faster reduction of relapse risk when none or only 1-2 CSV⁺ CTCs (every 6 mL) are present in the blood samples compared to >3 CSV⁺ CTCs. To the best of our knowledge, this is the first study that directly observes CTCs in under remission NB patients for relapse prediction and the first to gather sequential CSV⁺ CTC data in any study in a long-term longitudinal manner.

Circulating Tumor Cells in Metastatic Breast Cancer: Clinical Applications and Future Possibilities

Circulating tumor cells (CTCs) have gained importance as an emerging biomarker in solid tumors in the last two decades. Several detection assays have been introduced by various study groups, with EpCAM-based CellSearch system being the most widely used and standardized technique. In breast cancer, detection of CTCs correlates with clinical outcome in early and metastatic settings. CTC persistence beyond first cycle of palliative chemotherapy indicates poor response to treatment in metastatic situation. Beyond prognostication and therapy monitoring, CTC counts can guide treatment decisions in hormone receptor positive HER2-negative metastatic breast cancer. Furthermore, CTC-based therapy interventions are currently under investigation in clinical trials. In this review, we focus on the current state of knowledge and possible clinical applications of CTC diagnostics in patients with metastatic breast cancer.

53BP1 Accumulation in Circulating Tumor Cells Identifies Chemotherapy-Responsive Metastatic Breast Cancer Patients

Evidence suggests that the DNA end-binding protein p53-binding protein 1 (53BP1) is down-regulated in subsets of breast cancer. Circulating tumor cells (CTCs) provide accessible “biopsy material” to track cell traits and functions and their alterations during treatment. Here, we prospectively monitored the 53BP1 status in CTCs from 67 metastatic breast cancer (MBC) patients with HER2- CTCs and known hormone receptor (HR) status of the primary tumor and/or metastases before, during, and at the end of chemotherapeutic treatment with Eribulin. Nuclear 53BP1 staining and genomic integrity were evaluated by immunocytochemical and whole-genome-amplification-based polymerase chain reaction (PCR) analysis, respectively. Comparative analysis of CTCs from patients with triple-negative and HR+ tumors revealed elevated 53BP1 levels in CTCs from patients with HR+ metastases, particularly following chemotherapeutic treatment. Differences in nuclear 53BP1 signals did not correlate with genomic integrity in CTCs at baseline or with nuclear γH2AX signals in MBC cell lines, indicating that 53BP1 detected features beyond DNA damage. Kaplan–Meier analysis revealed an increasing association between nuclear 53BP1-positivity and progression-free survival (PFS) during chemotherapy until the final visit. Our data suggest that 53BP1 detection in CTCs could be a useful marker to capture dynamic changes of chemotherapeutic responsiveness in triple-negative and HR+ MBC.

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

Breast cancer metastasis is the leading cause of cancer deaths in women and is difficult to combat due to the long periods in which disseminated cells retain a potential to be re-activated and start the relapse. Assessing the number and molecular profile of circulating tumor cells (CTCs) in breast cancer patients, especially in early breast cancer, should help in identifying the possibility of relapse in time for therapeutic intervention to prevent or delay recurrence. While metastatic breast cancer is considered incurable, molecular analysis of CTCs still have a potential to define particular susceptibilities of the cells representing the current tumor burden, which may differ considerably from the cells of the primary tumor, and offer more tailored therapy to the patients. In this review we inspect the routes to metastasis and how they can be linked to specific features of CTCs, how CTC analysis may be used in therapy, and what is the current status of the research and efforts to include CTC analysis in clinical practice.

Circulating Tumor Cells (CTCs) Heterogeneity in Metastatic Breast Cancer: Different Approaches for Different Needs

In metastatic breast cancer the role of circulating tumor cells (CTCs) enumeration for predicting clinical outcome is supported by many studies, most of them dealing with strictly epithelial cells. However, it is becoming clear that CTCs are a heterogeneous cell population characterized by plasticity and including also cells which have lost the epithelial phenotype. Here we review literature data on CTC heterogeneity both at phenotype and at molecular level and discuss the possible contribute of single cell analyses in precision medicine. We conclude with some remarks about the steps still necessary to achieve clinical validity and utility when considering also CTC phenotypic and molecular heterogeneity beyond a simple enumeration.

de la Fuente J, Moros M. Nanoparticle-based biosensors for detection of extracellular vesicles in liquid biopsies

Selecting the appropriate nanoparticle, functionalization chemistry and sensing methodology can speed up the translation of liquid biopsies into the clinic.

Prognostic and therapeutic significance of circulating tumor cells in patients with lung cancer

BACKGROUND

Lung cancer is the second most common cancer and the main cause of cancer-related mortality worldwide. In spite of various efforts that have been made to facilitate the early diagnosis of lung cancer, most patients are diagnosed when the disease is already in stage IV, which is generally associated with the occurrence of distant metastases and a poor survival. Moreover, a large proportion of these patients will relapse after treatment, heralding the need for the stratification of lung cancer patients in addition to identifying those who are at a higher risk of relapse and, thus, require alternative and/or additional therapies. Recently, circulating tumor cells (CTCs) have been considered as valuable markers for the early diagnosis, prognosis and risk stratification of cancer patients, and they have been found to be able to predict the survival of patients with various types of cancer, including lung cancer. Additionally, the characterization of CTCs has recently provided fascinating insights into the heterogeneity of tumors, which may be instrumental for the development of novel targeted therapies.

CONCLUSIONS

Here we review our current understanding of the significance of CTCs in lung cancer metastasis. We also discuss prominent studies reporting the utility of enumeration and characterization of CTCs in lung cancer patients as prognostic and pharmacodynamic biomarkers for those who are at a higher risk of metastasis and drug resistance.

The prognostic role of circulating tumor cells in colorectal cancer

Introduction: Metastasis is the main cause of cancer-associated death in colorectal cancer (CRC). The presence of circulating tumor cells (CTC) in the blood is associated with an increased risk of recurrence and poor prognosis. The clinical significance of CTCs as a novel biomarker has been extensively studied in the last decade. It has been shown that CTC detection applies to early cancer detection. The presence of CTCs is associated with metastatic spread and poor survival and is also useful as a marker for therapy response.Areas covered: We summarize the role of CTC in CRC, their clinical significance, current methods for CTC detection and challenges as well as future perspectives of CTC research.Expert commentary: The clinical significance of CTC in CRC patients is well established. Although insightful, the available marker-based approaches hampered our understanding of the CTCs and their biology, as such approaches do not take into account the heterogeneity of these cell populations. New technologies should expand the marker-based detection to multi biomarker-based approaches together with recent technological advances in microfluidics for single cell enrichment and analysis.

CTC analysis: an update on technological progress

There is a growing need for a more accurate, real-time assessment of tumor status and the probability of metastasis, relapse, or response to treatment. Conventional means of assessment include imaging and tissue biopsies that can be highly invasive, may not provide complete information of the disease's heterogeneity, and not ideal for repeat analysis. Therefore, a less-invasive means of acquiring similar information at greater time points is necessary. Liquid biopsies are samples of a patients' peripheral blood and hold potential of addressing these criteria. Ongoing research has revealed that a tumor can release circulating cells, genetic materials (DNA or RNA), and exosomes into circulation. These potential biomarkers can be captured in a liquid biopsy and analyzed to determine disease status. To achieve these goals, numerous technologies have been developed. In this review, we discuss both prominent and newly developed technologies for circulating tumor cell capture and analysis and their clinical impact.

[Circulating tumor cells in pancreatic cancer : Results of morphological and molecular analyses and comparisons with the primary tumor]

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a disease with a poor prognosis. PDAC shows characteristic mutations within codon 12/13. Circulating tumor cells (CTC) detected in blood samples of patients with cancer are hypothesized as the means of systemic tumor spread. But less is known about morphological/molecular characteristics or the pathophysiological meaning of PDAC CTC.

OBJECTIVES

The aim of the study was a cytomorphological and genetic analysis of CTC from patients with PDAC followed by the correlation of the results with those of the corresponding tumor in the pancreas.

MATERIAL AND METHODS

Blood samples of 58 patients with PDAC and 10 "normal" control donors were processed through a size-based CTC isolation. KRAS-mutation analyses were performed for CTC and the primary tumor and the results were compared. Furthermore, their potential as a prognostic marker was evaluated.

RESULTS

In patients with different UICC stages CTC were detected, but not in normal control patients. There was a trend for a worse median overall survival (OS) for patients with >3 CTC/ml. Patients with a KRAS^G12V mutation showed a trend for a better median OS compared to those with other KRAS mutations (10 months) or even without KRAS mutation. Fifty-eight percent of the patients presented concordant KRAS mutations in the primary tumor and corresponding CTC, while 42% were discordant. The median OS for both groups was similar.

CONCLUSIONS

Detection and characterization of CTC (for example by KRAS mutation analysis) may be useful for prognosis. Furthermore, it expands our knowledge of tumor biology and may detect possible tumor heterogeneity regarding the mutation profile of some cancer types.

Cell-Free DNA in the Liquid Biopsy Context: Role and Differences Between ctDNA and CTC Marker in Cancer Management

Liquid biopsy is a new diagnostic concept to investigate the molecular features of solid tumors by blood, saliva, urine, and any other body fluids which show a source of potential biomarkers. In cancer patients, it is a simple and less invasive mean, representing a sustainable alternative to interrogate all tumor cells longitudinally, quantifying and characterizing the biological materials (DNAs, RNAs, proteins) which originate from cancer tissues. Circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) analysis from a simple blood draw received enormous attention for the related clinical research results. A rich scientific literature demonstrates that liquid biopsy is a valid instrument to assess the tumor biomarkers in real time and profile the cancer genotype in diagnostic and prognostic field, as well to quantify minimal residual disease, during patient follow-up. This could be a breakthrough for a companion diagnostic and personalized medicine. Liquid biopsy needs further implementation in the methodological aspects as well as cost-based assessment. The number of new molecular diagnostic assays increases day by day, but the standards for their adoption and clinical validation are still to be achieved.

Circulating biomarkers for early detection and clinical management of colorectal cancer

New non-invasive approaches that can complement and improve on current strategies for colorectal cancer (CRC) screening and management are urgently needed. A growing number of publications have documented that components of tumors, which are shed into the circulation, can be detected in the form of liquid biopsies and can be used to detect CRC at early stages, to predict response to certain therapies and to detect CRC recurrence in a minimally invasive way. The analysis of circulating tumor DNA (ctDNA), tumor-derived cells (CTC, circulating tumor cells) or circulating microRNA (miRNA) in blood and other body fluids, have a great potential to improve different aspects of CRC management. The challenge now is to find which types of components, biofluids and detection methods would be the most suitable to be applied in the different steps of CRC detection and treatment. This chapter will provide an up to date review on ctDNA, CTCs and circulating miRNAs as new biomarkers for CRC, either for clinical management or early detection, highlighting their advantages and limitations.

Human-specific RNA analysis shows uncoupled epithelial-mesenchymal plasticity in circulating and disseminated tumour cells from human breast cancer xenografts

Blood samples, bone marrow, tumours and metastases where possible were collected from SCID mice bearing orthotopic xenografts of the triple-negative MDA-MB-468 cell line or a transplantable ER-positive patient derived xenograft (ED-03), and assessed using human-specific, tandem-nested RT-qPCR for markers relating to detection of circulating (CTCs) and disseminated tumour cells (DTCs), breast cancer clinicopathology, the 'cancer stem cell' phenotype, metabolism, hypoxia and epithelial-mesenchymal plasticity (EMP). Increased levels of SNAI1, ILK, NOTCH1, CK20, and PGR, and a decrease/loss of EPCAM in CTCs/DTCs were observed relative to the primary xenograft across both models. Decreased CD24 and EGFR was restricted to the MDA-MB-468 model, while increased TFF1 was seen in the ED-03 model. The major metabolic regulator PPARGC1A, and several hypoxia-related markers (HIF1A, APLN and BNIP3) were significantly elevated in both models. Increased expression of mesenchymal markers including SNAI1 was seen across both models, however CDH1 did not decrease concordantly, and several other epithelial markers were increased, suggesting an uncoupling of EMP to produce an EMP hybrid or partial-EMT. Single cell analysis of ED-03 CTCs, although limited, indicated uncoupling of the EMP axis in single hybrid cells, rather than distinct pools of epithelial or mesenchymal-enriched cells, however dynamic heterogeneity between CTCs/DTCs cannot be ruled out. Reduced CD24 expression was observed in the MDA-MB-468 CTCs, consistent with the 'breast cancer stem cell' phenotype, and metastatic deposits in this model mostly resembled the primary xenografts, consistent with the mesenchymal-epithelial transition paradigm.

Epithelial-type systemic breast carcinoma cells with a restricted mesenchymal transition are a major source of metastasis

Carcinoma cells undergo epithelial-mesenchymal transition (EMT); however, contributions of EMT heterogeneity to disease progression remain a matter of debate. Here, we addressed the EMT status of ex vivo cultured circulating and disseminated tumor cells (CTCs/DTCs) in a syngeneic mouse model of metastatic breast cancer (MBC). Epithelial-type CTCs with a restricted mesenchymal transition had the strongest lung metastases formation ability, whereas mesenchymal-type CTCs showed limited metastatic ability. EpCAM expression served as a surrogate marker to evaluate the EMT heterogeneity of clinical samples from MBC, including metastases, CTCs, and DTCs. The proportion of epithelial-type CTCs, and especially DTCs, correlated with distant metastases and poorer outcome of patients with MBC. This study fosters our understanding of EMT in metastasis and underpins heterogeneous EMT phenotypes as important parameters for tumor prognosis and treatment. We further suggest that EpCAM-dependent CTC isolation systems will underestimate CTC numbers but will quantify clinically relevant metastatic cells.

HPV16 E6/E7 expression in circulating tumor cells in oropharyngeal squamous cell cancers: A pilot study

Objectives

Human papillomavirus-related oropharyngeal squamous cell carcinoma (HPV+ OPSCC) is increasing in incidence. Although HPV+ OPSCC has favorable prognosis, 10 to 25% of HPV+ OPSCCs eventually recur. We sought to evaluate the feasibility of detection of HPV16 E6/E7 expression in Circulating Tumor Cells (CTCs) and its utility as a prognostic tool in HPV16-associated OPSCC.

Materials and methods

We developed a highly sensitive RT-qPCR assay for HPV mRNA expression in EpCAM(+) CTCs. In 22 patients with early stage and locally advanced OPSCC we evaluated HPV16 E6/E7 expression in the EpCAM(+) CTC fraction at baseline and at the end of concurrent chemoradiotherapy. HPV status in pre-therapy formalin-fixed paraffin-embedded (FFPE) tumor biopsies was assessed by p16 immunohistochemistry and polymerase chain reaction (PCR) and double positives were subjected to Real-time qPCR assay for detection of HPV16, 18 and 31 types.

Results

Fourteen of 22 OPSCC (63.6%) were HPV DNA+/p16+. Among HPV+/p16+ patients, 10 patients (71.4%) were HPV16 DNA+. HPV16 E6/E7(+) CTCs were detected in 3 of 10 patients (30%) at baseline and 4 of 9 patients (44.4%) at the end-of-treatment, all of which were p16+/HPV16 DNA+. Survival analysis showed a significantly higher risk for disease relapse (p = 0.001) and death (p = 0.005) in patients with HPV16 E6/E7(+) baseline CTCs.

Conclusion

Detection of HPV E6/E7(+) CTCs might be a useful noninvasive test in liquid biopsy samples for determination of a clinically relevant HPV infection in HPV+ OPSCC. Combined interpretation of HPV E6/E7(+) CTCs with UICC staging data may lead to alteration of risk definition of patient subsets, with improved risk discrimination in early-stage disease.

Update Breast Cancer 2019 Part 2 - Implementation of Novel Diagnostics and Therapeutics in Advanced Breast Cancer Patients in Clinical Practice

The treatment of patients with advanced breast cancer has developed further in recent years. In addition to therapeutic progress in the established subgroups (hormone receptor and HER2 status), there are now therapies which are geared to individual molecular characteristics, such as PARP inhibitor therapy in BRCA-mutated patients. In addition to this, tests are being developed which are intended to establish additional markers within subgroups in order to predict the efficacy of a therapy. PI3K mutation testing in HER2-negative, hormone-receptor-positive tumours and PD-L1 testing of immune cells in triple-negative tumours are expected to become established in clinical practice in order to select patients for the respective therapies. With new therapeutic approaches, new adverse effects also appear. The management of these adverse effects, just as those of classical therapy (supportive therapy), is essential with the introduction of new treatments in order to preserve patients' quality of life. Knowledge regarding measures to preserve and improve quality of life has significantly increased in recent years. Lifestyle factors should be taken into account, as should modern therapeutic methods. This review summarises the latest studies and publications and evaluates them in regard to the relevance for clinical practice.

Circulating tumor cells in metastatic breast cancer: clinical relevance and biological potential

PURPOSE OF REVIEW

The possibility of tumor dissemination through the blood system has been known for years. Circulating tumor cells (CTCs) are detectable in the peripheral blood of patients with early as well as metastatic breast cancer. The prognostic relevance of this biomarker has already been described. By the use of repeated blood sampling along the course of disease, CTCs can be monitored in terms of a regular 'liquid biopsy'. This review aims to summarize recent research findings and actual ongoing clinical studies to demonstrate the actual and future relevance of CTCs in daily clinical routine.

RECENT FINDINGS

Recent research results show that additional molecular analysis of CTCs might be helpful in gaining information about tumor characteristics, tumor heterogeneity and possible therapy resistance. Repetitive invasive core biopsies might be avoided.

SUMMARY

The assessment of molecular attributes may be indispensable for obtaining an optimized and personalized therapy aiming at extended survival and/or improved quality of life.

Update Breast Cancer 2018 (Part 4) - Genomics, Individualized Medicine and Immune Therapies - in the Middle of a New Era: Treatment Strategies for Advanced Breast Cancer

New therapeutic developments aimed at treating women with advanced breast cancer currently focus both on identifying patients eligible for targeted therapeutic concepts and on the continuing development of immune therapies. The data on CDK4/6 inhibitors are now complete and consistent in this class of substances (palbociclib, ribociclib and abemaciclib). Further pathways under investigation are PI3K and AKT signalling pathways along with diverse approaches to their inhibition. Initial study results were also presented recently on both mechanisms of action. Insights into the PARP inhibitors, moreover, are increasing; studies in this respect are also examining in which population they can be used most effectively. This review offers a summary of the recent studies and an outline of the latest developments.

Liquid biopsy in pancreatic cancer: the beginning of a new era

With dismal survival rate pancreatic cancer remains one of the most aggressive and devastating malignancy. Predominantly, due to the absence of a dependable methodology for early identification and limited therapeutic options for advanced disease. However, it takes over 17 years to develop pancreatic cancer from initiation of mutation to metastatic cancer; therefore, if diagnosed early; it may increase overall survival dramatically, thus, providing a window of opportunity for early detection. Recently, genomic expression analysis defined 4 subtypes of pancreatic cancer based on mutated genes. Hence, we need simple and standard, minimally invasive test that can monitor those altered genes or their associated pathways in time for the success of precision medicine, and liquid biopsy seems to be one answer to all these questions. Again, liquid biopsy has an ability to pair with genomic tests. Additionally, liquid biopsy based development of circulating tumor cells derived xenografts, 3D organoids system, real-time monitoring of genetic mutations by circulating tumor DNA and exosome as the targeted drug delivery vehicle holds lots of potential for the treatment and cure of pancreatic cancer. At present, diagnosis of pancreatic cancer is frantically done on the premise of CA19-9 and radiological features only, which doesn't give a picture of genetic mutations and epigenetic alteration involved. In this manner, the current diagnostic paradigm for pancreatic cancer diagnosis experiences low diagnostic accuracy. This review article discusses the current state of liquid biopsy in pancreatic cancer as diagnostic and therapeutic tools and future perspectives of research in the light of circulating tumor cells, circulating tumor DNA and exosomes.

Functional Diagnostic and Therapeutic Nanoconstructs for Efficient Probing of Circulating Tumor Cells

The circulation of tumor cells in peripheral blood is mostly recognized as a prerequisite for cancer progression or systemic invasion, and it correlates with the pivotal hallmark of malignancies known as metastasis. Multiple detection schemes for circulating tumor cells (CTCs) have emerged as the most discerning criteria for monitoring the outcome of anticancer therapy. Therefore, there has been a tremendous increase in the use of robust nanostructured platforms for observation of these mobile tumor cells through various simultaneous diagnosis and treatment regimens developed from conventional techniques. This review seeks to give detailed information about the nature of CTCs as well as techniques for exploiting specific biomarkers to help monitor cancer via detection, capturing, and analysis of unstable tumor cells. We will further discuss nanobased diagnostic interventions and novel platforms which have recently been developed from versatile nanomaterials such as polymer nanocomposites, metal organic frameworks, bioderived nanomaterials and other physically responsive particles with desirable intrinsic and external properties. Herein, we will also include in vivo nanotheranostic platforms which have received a lot of attention because of their enormous clinical potential. In all, this review sums up the general potential of key promising nanoinspired systems as well as other advanced strategies under research and those in clinical use.