CTCs in early breast cancer: A path worth taking

A Bio-Inspired Free-Standing Film with Versatility: From Heterogeneous CTCs Programed Isolating to Breast Cancer Molecular Typing

Developing a robust strategy for profiling heterogeneous circular tumor cells specifically, distinguishing the phenotypes of which in blood sample of cancer patient precisely, and releasing them sequentially, is significant for cancer management by liquid biopsy. Herein, a bio-inspired free-standing and flexible film composed of TiO2 nanotube and silk fibroin, fabricated with multiply dynamic bioactive surface (TSF/MDBS) by a simple and eco-friendly way including using polydopamine chemistry and dual dynamic covalent chemistry, is reported. The as-prepared TSF/MDBS binds specific peptides toward cells with epithelial biomarker and human epithelial growth factor receptor 2 (HER2) biomarker, and antifouling agents bovine serum albumin for obviating platelets and proteins adhering of blood, can capture heterogeneous CTCs with enhanced capability due to the cytocompatible soft film and exquisite surface design, and further release the captured cells as program, by specifically breaking down the covalent bonds in sequence via the action of adding biocompatible molecules fructose and glutathione. By applying the TSF/MDBS, it can be tailored into desired pieces for identifying CTCs with different phenotypes (HER2-high and HER2-low) from the unprocessed blood samples of breast cancer patients, and finally profiling these heterogeneous CTCs, to discriminate HER2 positive or negative of breast cancer patients in clinical applications.

Multivalent aptamer nanoscaffold cytosensor for glioma circulating tumor cells during Epithelial-Mesenchymal transition

The key factor that causes glioma invasion and metastasis is circulating tumor cells (CTCs) undergoing epithelial-mesenchymal transition (EMT). Effective analysis of EMT-CTCs can provide an important foundation for early detection and prognosis monitoring of glioma, but the changes in the biomarkers of CTCs in different states of EMT make detection difficult. In this study, we developed a multivalent aptamer nanoscaffold-based electrochemical cytosensor (MAS-cytosensor) to efficiently detect EMT-CTCs. The two chains forming the MAS are composed of a specific aptamer detector, a binding region for DNA self-assembly, and a foothold for interface anchoring. When target CTCs exist, the bisaptamer detector on MAS can sensitively identify CTCs and pull them to the electrode surface, generating electrochemical signals. It has been demonstrated that the MAS-cytosensor can not only detect EMT-CTCs sensitively (detection limit of 6 cells/mL in buffer), but also allows for further downstream analysis after release with high viability. Overall, this cytosensor provides a reliable detection solution for CTCs regardless of their EMT status, and provides an efficient method for in-depth study role of the post-EMT CTCs in clinical application and metastasis mechanisms.

Fusion Cell Markers in Circulating Tumor Cells from Patients with High-Grade Ovarian Serous Carcinoma

Cancer is primarily a disease in which late diagnosis is linked to poor prognosis, and unfortunately, detection and management are still challenging. Circulating tumor cells (CTCs) are a potential resource to address this disease. Cell fusion, an event discovered recently in CTCs expressing carcinoma and leukocyte markers, occurs when ≥2 cells become a single entity (hybrid cell) after the merging of their plasma membranes. Cell fusion is still poorly understood despite continuous evaluations in in vitro/in vivo studies. Blood samples from 14 patients with high-grade serous ovarian cancer (A.C. Camargo Cancer Center, São Paulo, Brazil) were collected with the aim to analyze the CTCs/hybrid cells and their correlation to clinical outcome. The EDTA collected blood (6 mL) from patients was used to isolate/identify CTCs/hybrid cells by ISET. We used markers with possible correlation with the phenomenon of cell fusion, such as MC1-R, EpCAM and CD45, as well as CEN8 expression by CISH analysis. Samples were collected at three timepoints: baseline, after one month (first follow-up) and after three months (second follow-up) of treatment with olaparib (total sample = 38). Fourteen patients were included and in baseline and first follow-up all patients showed at least one CTC. We found expression of MC1-R, EpCAM and CD45 in cells (hybrid) in at least one of the collection moments. Membrane staining with CD45 was found in CTCs from the other cohort, from the other center, evaluated by the CellSearch^® system. The presence of circulating tumor microemboli (CTM) in the first follow-up was associated with a poor recurrence-free survival (RFS) (5.2 vs. 12.2 months; p = 0.005). The MC1-R expression in CTM in the first and second follow-ups was associated with a shorter RFS (p = 0.005). CEN8 expression in CTCs was also related to shorter RFS (p = 0.035). Our study identified a high prevalence of CTCs in ovarian cancer patients, as well as hybrid cells. Both cell subtypes demonstrate utility in prognosis and in the assessment of response to treatment. In addition, the expression of MC1-R and EpCAM in hybrid cells brings new perspectives as a possible marker for this phenomenon in ovarian cancer.

Unraveling the structures, functions and mechanisms of epithelial membrane protein family in human cancers

Peripheral myelin protein 22 (PMP22) and epithelial membrane proteins (EMP-1, -2, and -3) belong to a small hydrophobic membrane protein subfamily, with four transmembrane structures. PMP22 and EMPs are widely expressed in various tissues and play important roles in cell growth, differentiation, programmed cell death, and metastasis. PMP22 presents its highest expression in the peripheral nerve and participates in normal physiological and pathological processes of the peripheral nervous system. The progress of molecular genetics has shown that the genetic changes of the PMP22 gene, including duplication, deletion, and point mutation, are behind various hereditary peripheral neuropathies. EMPs have different expression patterns in diverse tissues and are closely related to the risk of malignant tumor progression. In this review, we focus on the four members in this protein family which are related to disease pathogenesis and discuss gene mutations and post-translational modification of them. Further research into the interactions between structural alterations and function of PMP22 and EMPs will help understand their normal physiological function and role in diseases and might contribute to developing novel therapeutic tools.

CNA Profiling of Single CTCs in Locally Advanced Esophageal Cancer Patients during Therapy Highlights Unexplored Molecular Pathways

BACKGROUND

Here, we monitored the evolution of CTCs spread in 11 patients affected by locally advanced EC who were undergoing therapy.

METHODS

In this perspective study, we designed multiple blood biopsies from individual patients: before and after neoadjuvant chemo-radio therapy and after surgery. We developed a multi-target array, named Grab-all assay, to estimate CTCs for their epithelial (EpCAM/E-Cadherin/Cytokeratins) and mesenchymal/stem (N-Cadherin/CD44v6/ABCG2) phenotypes. Identified CTCs were isolated as single cells by DEPArray, subjected to whole genome amplification, and copy number aberration (CNA) profiles were determined. Through bioinformatic analysis, we assessed the genomic imbalance of single CTCs, investigated specific focal copy number changes previously reported in EC and aberrant pathways using enrichment analysis.

RESULTS

Longitudinal monitoring allowed the identification of CTCs in at least one time-point per patient. Through single cell CNA analysis, we revealed that CTCs showed significantly dynamic genomic imbalance during treatment. Individual CTCs from relapsed patients displayed a higher degree of genomic imbalance relative to disease-free patients' groups. Genomic aberrations previously reported in EC occurred mostly in post-neoadjuvant therapy CTCs. In-depth analysis showed that networks enrichment in all time-point CTCs were inherent to innate immune system. Transcription/gene regulation, post-transcriptional and epigenetic modifications were uniquely affected in CTCs of relapsed patients.

CONCLUSIONS

Our data add clues to the comprehension of the role of CTCs in EC aggressiveness: chromosomal aberrations on genes related to innate immune system behave as relevant to the onset of CTC-status, whilst pathways of transcription/gene regulation, post-transcriptional and epigenetic modifications seem linked to patients' outcome.

Prediction of Late Recurrence and Distant Metastasis in Early-stage Breast Cancer: Overview of Current and Emerging Biomarkers

Recently, a significant number of breast cancer (BC) patients have been diagnosed at an early stage. It is therefore critical to accurately predict the risk of recurrence and distant metastasis for better management of BC in this setting. Clinicopathologic patterns, particularly lymph node status, tumor size, and hormonal receptor status are routinely used to identify women at increased risk of recurrence. However, these factors have limitations regarding their predictive ability for late metastasis risk in patients with early BC. Emerging molecular signatures using gene expression-based approaches have improved the prognostic and predictive accuracy for this indication. However, the use of their based-scores for risk assessment has provided contradictory findings. Therefore, developing and using newly emerged alternative predictive and prognostic biomarkers for identifying patients at high- and low-risk is of great importance. The present review discusses some serum biomarkers and multigene profiling scores for predicting late recurrence and distant metastasis in early-stage BC based on recently published studies and clinical trials.

Liquid Biopsy in Breast Cancer: Circulating Tumor Cells and Circulating Tumor DNA

Cancer is associated with gene mutations, and the analysis of tumor-associated mutations is increasingly used for diagnostic, prognostic, and treatment purposes. These molecular landscapes of solid tumors are currently obtained from surgical or biopsy specimens. However, during cancer progression and treatment, selective pressures lead to additional genetic changes as tumors acquire drug resistance. Tissue sampling cannot be performed routinely owing to its invasive nature and a single biopsy only provides a limited snapshot of a tumor, which may fail to reflect spatial and temporal heterogeneity. This dilemma may be solved by analyzing cancer cells or cancer cell-derived DNA from blood samples, called liquid biopsy. Liquid biopsy is one of the most rapidly advancing fields in cancer diagnostics and recent technological advances have enabled the detection and detailed characterization of circulating tumor cells and circulating tumor DNA in blood samples.Liquid biopsy is an exciting area with rapid advances, but we are still at the starting line with many challenges to overcome. In this chapter we will explore how tumor cells and tumor-associated mutations detected in the blood can be used in the clinic. This will include detection of cancer, prediction of prognosis, monitoring systemic therapies, and stratification of patients for therapeutic targets or resistance mechanisms.

Biomarkers in Triple-Negative Breast Cancer: State-of-the-Art and Future Perspectives

Triple-negative breast cancer (TNBC) is a heterogeneous group of tumors characterized by aggressive behavior, high risk of distant recurrence, and poor survival. Chemotherapy is still the main therapeutic approach for this subgroup of patients, therefore, progress in the treatment of TNBC remains an important challenge. Data derived from molecular technologies have identified TNBCs with different gene expression and mutation profiles that may help developing targeted therapies. So far, however, only a few of these have shown to improve the prognosis and outcomes of TNBC patients. Robust predictive biomarkers to accelerate clinical progress are needed. Herein, we review prognostic and predictive biomarkers in TNBC, discuss the current evidence supporting their use, and look at the future of this research field.

Liquid Biopsy as Novel Tool in Precision Medicine: Origins, Properties, Identification and Clinical Perspective of Cancer's Biomarkers

In recent years, there has been an increase in knowledge of cancer, accompanied by a technological development that gives rise to medical oncology. An instrument that allows the implementation of individualized therapeutic strategies is the liquid biopsy. Currently, it is the most innovative methodology in medical oncology. Its high potential as a tool for screening and early detection, the possibility of assessing the patient’s condition after diagnosis and relapse, as well as the effectiveness of real-time treatments in different types of cancer. Liquid biopsy is capable of overcoming the limitations of tissue biopsies. The elements that compose the liquid biopsy are circulating tumor cells, circulating tumor nucleic acids, free of cells or contained in exosomes, microvesicle and platelets. Liquid biopsy studies are performed on various biofluids extracted in a non-invasive way, and they can be performed both from the blood and in urine, saliva or cerebrospinal fluid. The development of genotyping techniques, using the elements that make up liquid biopsy, make it possible to detect mutations, intertumoral and intratumoral heterogeneity, and provide molecular information on cancer for application in medical oncology in an individualized way in different types of tumors. Therefore, liquid biopsy has the potential to change the way medical oncology could predict the course of the disease.

Selection of Aptamers Against Vimentin for Isolation and Release of Circulating Tumor Cells Undergoing Epithelial Mesenchymal Transition

Circulating tumor cells (CTCs) undergoing epithelial mesenchymal transition (EMT) play an essential role in metastasis and have a better correlation with poor disease outcomes, but the most current affinity-based enrichment methods rely on targeting epithelial markers, which are less effective in capturing CTCs undergoing EMT. Herein, we identified and optimized an aptamer (ZY5C) sequence with high binding affinity and specificity against cell surface vimentin (CSV), which is overexpressed on the post-EMT CTCs. Not only can the hairpin-structured ZY5C aptamer specifically recognize a number of cancer cells with native CSV expression, but it can also bind to CSV expressed on EMT-cells. The K_d value of the ZY5C aptamer against CSV-positive T24 cells was found to be 38 ± 4 nM. Using the evolved ZY5C aptamer and multivalent ZY5C aptamer-functionalized chip, we were able to isolate CTCs from the blood of adenocarcinoma, sarcoma, and carcinosarcoma patients. Overall, this ZY5C aptamer and isolation method bring a fresh approach to CTCs analysis, which not only detects CTCs from nonepithelial origin, but also provides an efficient way to in-depth study the role of post-EMT CTCs in clinical application and metastasis mechanisms.

Prospective study of the relevance of circulating tumor cell status and neoadjuvant chemotherapy effectiveness in early breast cancer

Although unequivocal evidence has shown the prognostic relevance of circulating tumor cells (CTCs) in patients with metastatic breast cancer (MBC), less evidence is available for its significance in neoadjuvant chemotherapy (NCT) in early breast cancer (BC). Here we conducted an analysis of individual data from 86 patients confirmed as invasive BC by core‐needle biopsy in Zhejiang Provincial People's Hospital between June 2013 and January 2017. The CTCs were assessed at the time after diagnosis and before surgery with the CanPatrol technique. The median follow‐up duration was 46.3 months. CTCs were detected in 37.2% of all patients (29/78) at baseline, and the presence of CTCs was associated with tumor size, tumor stage, and molecular classification. After NCT, the CTC‐positive patients were dropped from 29 to 8, and the EC‐T (epirubicin/cyclophosphamide followed by docetaxel) and TEC (docetaxel/epirubicin/cyclophosphamide) strategies reduce CTC‐positive patients from 16 to 3 and 13 to 5, respectively. The CTC‐negative conversion rates were similar in ER/PR+ HER2+ (5/7, 71.4%), ER/PR− HER2+ (8/11, 72.7%), and TNBC (7/10, 70%) during NCT. In addition, we explored the association between CTC‐negative conversion and objective response rate (partial response and complete response, ORR) and pathological complete response rate (pCR), and our results indicate that ORR was higher in patients with positive CTCs and converted to negative after NCT (ORR, P = .013; pCR, P = .0608). Our study preliminarily highlights the relevance of CTC status and NCT effectiveness in early BC using the CanPatrol system.

Circulating Tumor Cells: Applications for Early Breast Cancer

Breast cancer is the most common malignancy among women. Most of breast cancer patients are diagnosed in early stages and will be treated with curative intent. Despite this, some patients will relapse. The identification of patients at high risk remains an important challenge. CTCs can be useful to identify this patients, to assess tumor dynamics and to monitoring therapy. There is definitive evidence on the prognostic role of CTCs in early breast cancer (eBC) but its clinical utility in daily practice is still lacking. We have to take into consideration that the studies published to date mainly evaluated the presence of CTC based on the expression of epithelial surface markers. Future studies need to overcome this limitation and important advances in technical methods can assess CTCs and capture the heterogeneity of the tumor landscape. It is also tempting to speculate that CTCs may also provide complementary information on the interplay of tumor cells with the immune system. The combination of different methods to detect tumoral disease by liquid biopsy may provide new ways to personalize in an unprecedented manner the management of patients with eBC.

Know your enemy: Genetics, aging, exposomic and inflammation in the war against triple negative breast cancer

Triple negative breast cancer (TNBC) is one of the most biologically aggressive and very often lethal breast disease. It is one of the most puzzling women malignancies, and it currently appears not to be a good candidate to a standardized, unanimously accepted and sufficiently active therapeutic strategy. Fast proliferating and poorly differentiated, it is histopathologically heterogeneous, and even more ambiguous at the molecular level, offering few recurrent actionable targets to the clinicians. It is a formidable and vicious enemy that requires a huge investigational effort to find its vital weak spots. Here, we provide a broad review of "old but gold" biological aspects that taken together may help in finding new TNBC management strategies. A better and updated knowledge of the origins, war-like tactics, refueling mechanisms and escape routes of TNBC, will help in moving the decisive steps towards its final defeat.

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.

Epithelial membrane protein 2: a novel biomarker for circulating tumor cell recovery in breast cancer

PURPOSE

EpCAM is a common marker used in the detection of circulating tumor cells (CTC). Disseminated cancer cells display the characteristics of epithelial-to-mesenchymal transition events. The purpose of this study was to assess the potential of epithelial membrane protein 2 (EMP2) as a novel biomarker for CTC retrieval in breast cancer.

METHODS

MCF7 and MDA-MB-231 cells were stained with either anti-EpCAM or anti-EMP2 mAbs, respectively, followed by flow cytometric assay to measure their expression levels. PBMCs isolated from healthy donors were used for breast cancer cell spiking. CD45-depleted PBMCs from breast cancer patients' blood were used for CTC capturing. Immunomagnetic separation was used to enrich breast cancer cells. Cytospin centrifugation was performed to concentrate the captured cells, followed by immunofluorescence staining with anti-CD45 mAb, anti-pan cytokeratin mAb and DAPI. Fluorescent images were taken using a confocal microscope for CTC counts.

RESULT

MDA-MB-231 cells had 2.56 times higher EMP2 expression than MCF7 cells, and EMP2 had a significantly higher capture efficiency than EpCAM for MCF7 cells. Furthermore, anti-EMP2 was capable of capturing MCF7 cells that escaped in the flow-through of anti-EpCAM. Likewise, EMP2 had a significantly higher capture efficiency on MDA-MB-231 cells when compared to MCF7 cells. Most importantly, EMP2 biomarker was successfully used for CTC capture in patients with primary breast cancer.

CONCLUSIONS

EMP2 is superior to EpCAM for capturing both MCF7 and MDA-MB-231 cells. Additionally, EMP2 is a novel biomarker and capable of capturing breast cancer cells in patient blood samples.

Circulating tumor cell status monitors the treatment responses in breast cancer patients: a meta-analysis

Whether circulating tumor cells (CTCs) can be used as an indicator of treatment response in breast cancer (BC) needs to be clarified. We addressed this issue by a meta-analysis. PubMed, EMBase and Cochrane library databases were searched in June 2016. Effect measures were estimated as pooled risk ratio (RR), odds ratio (OR) or mean difference by fixed- or random-effect models, according to heterogeneity of included studies. In total, 50 studies with 6712 patients were recruited. Overall analysis showed that there was a significant reduction of CTC-positive rate (RR = 0.68, 95% CI: 0.61–0.76, P < 0.00001) after treatment. Subgroup analyses revealed that neoadjuvant treatment, adjuvant treatment, metastatic treatment or combination therapy could reduce the CTC-positive rate, but surgery could not; moreover, the reduction was only found in HER2+ or HER2- patients but not in the triple-negative ones. Reduction of CTC-positive rate was associated with lower probability of disease progression (OR = 0.54, 95% CI: 0.33–0.89, P = 0.01) and longer overall survival period (mean difference = 11.61 months, 95% CI: 8.63–14.59, P < 0.00001) as well as longer progression-free survival period (mean difference = 5.07 months, 95% CI: 2.70–7.44, P < 0.0001). These results demonstrate that CTC status can serve as an indicator to monitor the effectiveness of treatments and guide subsequent therapies in BC.

Circulating Tumor Cells in the Adenocarcinoma of the Esophagus

Circulating tumor cells (CTCs) are elements of indisputable significance as they seem to be responsible for the onset of metastasis. Despite this, research into CTCs and their clinical application have been hindered by their rarity and heterogeneity at the molecular and cellular level, and also by a lack of technical standardization. Esophageal adenocarcinoma (EAC) is a highly aggressive cancer that is often diagnosed at an advanced stage. Its incidence has increased so much in recent years that new diagnostic, prognostic and predictive biomarkers are urgently needed. Preliminary findings suggest that CTCs could represent an effective, non-invasive, real-time assessable biomarker in all stages of EAC. This review provides an overview of EAC and CTC characteristics and reports the main research results obtained on CTCs in this setting. The need to carry out further basic and translational research in this area to confirm the clinical usefulness of CTCs and to provide oncologists with a tool to improve therapeutic strategies for EAC patients was herein highlighted.