Molecular characterization of circulating tumor cells-from bench to bedside

Circulating tumor cell phenotype detection based on epithelial-mesenchymal transition markers combined with clinicopathological risk has potential to better predict recurrence in stage III breast cancer treated with neoadjuvant chemotherapy: a pilot study

BACKGROUND

The potential value of detecting epithelial-mesenchymal transition (EMT) CTCs in early breast cancer, especially during the neoadjuvant therapy period, requires further investigation. We analyzed dynamic CTC phenotype status, to improve recurrence risk stratification for patients with stage III breast cancers.

METHODS

We enrolled 45 patients with stage III breast cancers from 2 clinical trials undergoing neoadjuvant chemotherapy and utilized the CanPatrol CTC enrichment technique pre- and post-chemotherapy to identify CTC phenotypes, including epithelial CTCs, biphenotypic epithelial/mesenchymal CTCs, and mesenchymal CTCs, in peripheral blood samples. Kaplan-Meier analyses were conducted to explore the prognostic value of dynamic change of CTC count and the proportion of CTCs with different phenotypes. Then, redefine the risk stratification based on CTC status and clinicopathological risk in combination.

RESULTS

Increased proportion of M + CTCs was a high-risk CTC status that was associated with decreased DFS (HR, 3.584; 95% CI, 1.057-12.15). In a combined analysis with clinicopathological risk, patients with high-risk tumors had an elevated risk of recurrence compared to patients with low-risk tumors (HR, 4.482; 95% CI, 1.246-16.12). The recurrence risk could be effectively stratified by newly defined risk stratification criteria, with 5-year DFS of 100.0%, 77.3%, and 50.0%, respectively, for low-risk, mid-risk, and high-risk patients (P = 0.0077). Finally, in the ROC analysis, the redefined risk stratification demonstrated higher predictive significance with an AUC of 0.7727, compared to CTC status alone (AUC of 0.6751) or clinicopathological risk alone (AUC of 0.6858).

CONCLUSION

The proportion of M + CTCs increased after neoadjuvant chemotherapy indicating a higher risk of tumor recurrence. Combining CTC status with clinicopathological risk has potential to redefine the risk stratification of stage III breast cancers and provide improved predictions of relapse.

Research progress of CTC, ctDNA, and EVs in cancer liquid biopsy

Circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), and extracellular vehicles (EVs) have received significant attention in recent times as emerging biomarkers and subjects of transformational studies. The three main branches of liquid biopsy have evolved from the three primary tumor liquid biopsy detection targets-CTC, ctDNA, and EVs-each with distinct benefits. CTCs are derived from circulating cancer cells from the original tumor or metastases and may display global features of the tumor. ctDNA has been extensively analyzed and has been used to aid in the diagnosis, treatment, and prognosis of neoplastic diseases. EVs contain tumor-derived material such as DNA, RNA, proteins, lipids, sugar structures, and metabolites. The three provide different detection contents but have strong complementarity to a certain extent. Even though they have already been employed in several clinical trials, the clinical utility of three biomarkers is still being studied, with promising initial findings. This review thoroughly overviews established and emerging technologies for the isolation, characterization, and content detection of CTC, ctDNA, and EVs. Also discussed were the most recent developments in the study of potential liquid biopsy biomarkers for cancer diagnosis, therapeutic monitoring, and prognosis prediction. These included CTC, ctDNA, and EVs. Finally, the potential and challenges of employing liquid biopsy based on CTC, ctDNA, and EVs for precision medicine were evaluated.

Magnetically-activated, nanostructured cellulose for efficient capture of circulating tumor cells from the blood sample of head and neck cancer patients

In this report, the relative efficiency of cellulose nanocrystals (CNCs) and nanofibers (CNFs) to capture circulating tumor cells (CTCs) from the blood sample of head and neck cancer (HNC) patients was evaluated. Detection and enumeration of CTCs are critical for monitoring cancer progression. Both types of nanostructured cellulose were chemically modified with Epithelial Cell Adhesion Molecule (EpCAM) antibody and iron oxide nanoparticles. The EpCAM antibody facilitated the engagement of CTCs, promoting entrapment within the cellulose cage structure. Iron oxide nanoparticles, on the other hand, rendered the cages activatable via the use of a magnet for the capture and separation of entrapped CTCs. The efficiency of the network structures is shown in head and neck cancer (HNC) patients' blood samples. It was observed that the degree of chemical functionalization of hydroxyl groups located within the CNCs or CNFs with anti-EpCAM determined the efficiency of the system's interaction with CTCs. Further, our result indicated that inflexible scaffolds of nanocrystals interacted more efficiently with CTCs than that of the fibrous CNF scaffolds. Network structures derived from CNCs demonstrated comparable CTC capturing efficiency to commercial standard, OncoDiscover®. The output of the work will provide the chemical design principles of cellulosic materials intended for constructing affordable platforms for monitoring cancer progression in 'real time'.

Circulating tumor cells as potential prognostic biomarkers for early-stage pancreatic cancer: A systematic review and meta-analysis

BACKGROUND

Pancreatic cancer is difficult to be diagnosed early clinically, while often leads to poor prognosis. If optimal personalized treatment plan can be provided to pancreatic cancer patient at an earlier stage, this can greatly improve overall survival (OS). Circulating tumor cells (CTCs) are a collective term for various types of tumor cells present in the peripheral blood (PB), which are formed by detachment during the development of solid tumor lesions. Most CTCs undergo apoptosis or are phagocytosed after entering the PB, whereas a few can escape and anchor at distal sites to develop metastasis, increasing the risk of death for patients with malignant tumors.

AIM

To investigate the significance of CTCs in predicting the prognosis of early pancreatic cancer patients.

METHODS

The PubMed, EMBASE, Web of Science, Cochrane Library, China National Knowledge Infrastructure, China Biology Medicine, and ChinaInfo databases were searched for articles published through December 2022. Studies were considered qualified if they included patients with early pancreatic cancer, analyzed the prognostic value of CTCs, and were full papers reported in English or Chinese. Researches were selected and assessed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol and the Newcastle-Ottawa Scale criteria. We used a funnel plot to assess publication bias.

RESULTS

From 1595 publications, we identified eight eligible studies that collectively enrolled 355 patients with pancreatic cancer. Among these original studies, two were carried out in China; three in the United States; and one each in Italy, Spain, and Norway. All eight studies analyzed the relevance between CTCs and the prognosis of patients with early-stage pancreatic cancer after surgery. A meta-analysis showed that the patients that were positive pre-treatment or post-treatment for CTCs were associated with decreased OS [hazard ratio (HR) = 1.93, 95% confidence interval (CI): 1.197-3.126, P = 0.007] and decreased relapse-free/disease-free/progression-free survival (HR = 1.27, 95%CI: 1.137-1.419, P < 0.001) in early-stage pancreatic cancer. Additionally, the results suggest no statistically noticeable publication bias for overall, disease-free, progression-free, and recurrence-free survival.

CONCLUSION

This pooled meta-analysis shows that CTCs, as biomarkers, can afford reliable prognostic information for patients with early-stage pancreatic cancer and help develop individualized treatment plans.

Circulating Tumor Cells as Predictive and Prognostic Biomarkers in Solid Tumors

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

Circulating tumor cells in cancer-risk populations as a cancer interception tool

Cancer interception (CI) is a new approach to cancer prevention and treatment in a cancer-risk population that aims to detect and treat pre-tumoral stages. It has several potential advantages over traditional cancer diagnosis and monitoring methods because it is non-invasive, making it less painful and risky than conventional biopsy procedures. The circulating tumor cells (CTCs), liquid biopsy family members, are essential for the CI approach; then, the liquid biopsy (LB) is used as a CI tool. LB can be performed frequently because of its easy sampling and early pathological stages, which allow repeated non-invasive monitoring of cancer progression and response to treatment. CTCs have been found in the bloodstream of several types of cancer patients, including in early-stage cancer and premalignant lesions, suggesting a tumor development role in cancer's early stages. This chapter will present foundational scientific studies addressing CI and the clinical impact of CTC screening in a population at risk for cancer.

Recent Advances in Methods for Circulating Tumor Cell Detection

Circulating tumor cells (CTCs) are released from primary tumors and transported through the body via blood or lymphatic vessels before settling to form micrometastases under suitable conditions. Accordingly, several studies have identified CTCs as a negative prognostic factor for survival in many types of cancer. CTCs also reflect the current heterogeneity and genetic and biological state of tumors; so, their study can provide valuable insights into tumor progression, cell senescence, and cancer dormancy. Diverse methods with differing specificity, utility, costs, and sensitivity have been developed for isolating and characterizing CTCs. Additionally, novel techniques with the potential to overcome the limitations of existing ones are being developed. This primary literature review describes the current and emerging methods for enriching, detecting, isolating, and characterizing CTCs.

MagPure chip: an immunomagnetic-based microfluidic device for high purification of circulating tumor cells from liquid biopsies

The isolation of circulating tumor cells (CTCs) directly from blood, as a liquid biopsy, could lead to a paradigm shift in cancer clinical care by providing an earlier diagnosis, a more accurate prognosis, and personalized treatment. Nevertheless, CTC-specific challenges, including their rarity and heterogeneity, have hampered the wider use of CTCs in clinical studies. Microfluidic-based isolation technologies have emerged as promising tools to circumvent these limitations but still fail to meet the constraints of high purity and short processing time required to ensure compatibility with clinical follow-up. In this study, we developed an immunomagnetic-based microfluidic device, the MagPure chip, to achieve the negative selection of CTCs through the depletion of white blood cells (WBCs) and provide highly purified samples for subsequent analysis. We demonstrate that the MagPure chip depletes all magnetically labeled WBCs (85% of WBCs were successfully labeled) and ensures a CTC recovery rate of 81%. In addition, we show its compatibility with conventional biological studies, including 2D and 3D cell culture, as well as phenotypic and genotypic analyses. Finally, we successfully implemented a two-step separation workflow for whole blood processing by combining a size-based pre-enrichment system (ClearCell FX1®) with the MagPure chip as a subsequent purification step. The total workflow led to high throughput (7.5 mL blood in less than 4 h) and high purity (947 WBCs per mL remaining, 99.99% depletion rate), thus enabling us to quantify CTC heterogeneity in size and tumor marker expression level. This tumor-marker-free liquid biopsy workflow could be used in a clinical context to assess phenotype aggressiveness and the prognosis rate.

Diagnostic and prognostic biomarkers in colorectal cancer and the potential role of exosomes in drug delivery

Colorectal cancer (CRC) is third most common cancer with second most common cause of death worldwide. One fourth to one fifth of the CRC cases are detected at advance stage. Early detection of colorectal cancer might help in decreasing mortality and morbidity worldwide. CRC being a heterogeneous disease, new non-invasive approaches are needed to complement and improve the screening and management of CRC. Reliable and early detectable biomarkers would improve diagnosis, prognosis, therapeutic responses, and will enable the prediction of drug response and recurrence risk. Over the past decades molecular research has demonstrated the potentials of CTCs, ctDNAs, circulating mRNA, ncRNAs, and exosomes as tumor biomarkers. Non-invasive screening approaches using fecal samples for identification of altered gut microbes in CRC is also gaining attention. Exosomes can be potential candidates that can be employed in the drug delivery system. Further, the integration of in vitro, in vivo and in silico models that involve CRC biomarkers will help to understand the interactions occurring at the cellular level. This review summarizes recent update on CRC biomarkers and their application along with the nanoparticles followed by the application of organoid culture in CRC.

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

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

Designer tetrahedral DNA framework-based microfluidic technology for multivalent capture and release of circulating tumor cells

Circulating tumor cells (CTCs) have been recognized as a general biomarker for the early detection, diagnosis and therapy monitoring of cancer. Due to their extreme rarity in peripheral blood, the isolation and analysis of CTCs with high efficiency, high purity and high viability remains a tremendous technological challenge. Herein, we combined tetrahedral DNA framework (TDFs), herringbone channel (HB) chip, together with aptamer-triggered hybridization chain reaction (apt-HCR) to develop an efficient microfluidic system (T-μFS) for capture and release of simulated CTCs. The capture efficiency of MCF-7 ​cells was from 83.3% to 94.2% when the cell numbers ranged from 10 to 10³ using our T-μFS in the whole blood. The release efficiency of the MCF-7 ​cells was 96.2% and the MCF-7 ​cell viability after release was 94.6% using our T-μFS in PBS buffer. Reculture and RT-qPCR studies showed that there was almost no damage by the capture and release treatment for the MCF-7 ​cells viability. These results revealed that our T-μFS could be developed as an integrated and automatic technical platform with great performance for multivalent capture and release of CTCs and have a wide application prospect for tumor liquid biopsy.

•

Three-dimensional amine modified tetrahedral DNA frameworks (TDFs) as rigid scaffolds were anchored on the aldehyde modified substrate of HB-chip, which provided the better spatial orientation compared with single-stranded DNA.

•

Aptamer partially hybridized to an initiator was employed to trigger HCR reaction, and HCR produced modified long products with multi-branched arms for multivalent binding on TDFs to improve the capture efficiency of CTCs.

•

This is the first time that only employed DNA nanostructures in a microfluidic device system to capture CTCs, and all DNA nanostructures could be efficiently removed by enzymes without harming cells.

Circulating tumor cells: biology and clinical significance

Circulating tumor cells (CTCs) are tumor cells that have sloughed off the primary tumor and extravasate into and circulate in the blood. Understanding of the metastatic cascade of CTCs has tremendous potential for the identification of targets against cancer metastasis. Detecting these very rare CTCs among the massive blood cells is challenging. However, emerging technologies for CTCs detection have profoundly contributed to deepening investigation into the biology of CTCs and have facilitated their clinical application. Current technologies for the detection of CTCs are summarized herein, together with their advantages and disadvantages. The detection of CTCs is usually dependent on molecular markers, with the epithelial cell adhesion molecule being the most widely used, although molecular markers vary between different types of cancer. Properties associated with epithelial-to-mesenchymal transition and stemness have been identified in CTCs, indicating their increased metastatic capacity. Only a small proportion of CTCs can survive and eventually initiate metastases, suggesting that an interaction and modulation between CTCs and the hostile blood microenvironment is essential for CTC metastasis. Single-cell sequencing of CTCs has been extensively investigated, and has enabled researchers to reveal the genome and transcriptome of CTCs. Herein, we also review the clinical applications of CTCs, especially for monitoring response to cancer treatment and in evaluating prognosis. Hence, CTCs have and will continue to contribute to providing significant insights into metastatic processes and will open new avenues for useful clinical applications.

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.

In Vitro Magnetic Techniques for Investigating Cancer Progression

Worldwide, there are currently around 18.1 million new cancer cases and 9.6 million cancer deaths yearly. Although cancer diagnosis and treatment has improved greatly in the past several decades, a complete understanding of the complex interactions between cancer cells and the tumor microenvironment during primary tumor growth and metastatic expansion is still lacking. Several aspects of the metastatic cascade require in vitro investigation. This is because in vitro work allows for a reduced number of variables and an ability to gather real-time data of cell responses to precise stimuli, decoupling the complex environment surrounding in vivo experimentation. Breakthroughs in our understanding of cancer biology and mechanics through in vitro assays can lead to better-designed ex vivo precision medicine platforms and clinical therapeutics. Multiple techniques have been developed to imitate cancer cells in their primary or metastatic environments, such as spheroids in suspension, microfluidic systems, 3D bioprinting, and hydrogel embedding. Recently, magnetic-based in vitro platforms have been developed to improve the reproducibility of the cell geometries created, precisely move magnetized cell aggregates or fabricated scaffolding, and incorporate static or dynamic loading into the cell or its culture environment. Here, we will review the latest magnetic techniques utilized in these in vitro environments to improve our understanding of cancer cell interactions throughout the various stages of the metastatic cascade.

Distribution and Clinical Analysis of EpCAM+/Vimentin+ Circulating Tumor Cells in High-Risk Population and Cancer Patients

Circulating Tumor Cells (CTCs) are already present in the peripheral blood of patients with early tumors and even precancerous lesions. The objective of this study was to determine the count of CTCs in peripheral blood from high-risk population(HRP), healthy subjects and patients with Pan-cancer. The CTCs in the peripheral blood from HRP and cancer patients were enriched and identified based on the positive sorting method by epithelial cell adhesion molecular (EpCAM) liposome magnetic bead (Ep-LMB) and Vimentin liposome magnetic bead (Vi-LMB). Simultaneously, further analysis was carried out focusing on the clinical characteristics of patients by collecting the peripheral blood samples from healthy subjects as the parallel control. According to the results, the prepared LMBs had high specificity and stability, resulting in an average (Av) proliferation rate of over 90% for each cell line, and the average capture rate of higher than 80%. In terms of CTCs count detection in clinical blood samples, the average count was 0.9 (Ep: Av=0.6, Vi: Av=0.3), 2.4 (Ep: Av=1.4, Vi: Av=0.8) and 7.3 (Ep: Av=4.0, Vi: Av=3.3) in healthy subjects, HRP and total cancer patients, respectively. Besides, there was no obvious difference in the average count of CTCs among patients with different cancer types. While count of CTCs in the aforementioned cancer patients was statistically different from that in healthy subjects and patients with HRP. The survival time of cancer patients whose number of CTCs is greater than the average is significantly increased. Collectively, the study confirmed that CTCs can achieve early tumor detection and auxiliary diagnosis, and its number is related to the occurrence and development of tumors, and CTCs can be detected in HRP and sub-health population.

Next-Generation Sequencing with Liquid Biopsies from Treatment-Naïve Non-Small Cell Lung Carcinoma Patients

Recently, the liquid biopsy (LB), a non-invasive and easy to repeat approach, has started to compete with the tissue biopsy (TB) for detection of targets for administration of therapeutic strategies for patients with advanced stages of lung cancer at tumor progression. A LB at diagnosis of late stage non-small cell lung carcinoma (NSCLC) is also being performed. It may be asked if a LB can be complementary (according to the clinical presentation or systematics) or even an alternative to a TB for treatment-naïve advanced NSCLC patients. Nucleic acid analysis with a TB by next-generation sequencing (NGS) is gradually replacing targeted sequencing methods for assessment of genomic alterations in lung cancer patients with tumor progression, but also at baseline. However, LB is still not often used in daily practice for NGS. This review addresses different aspects relating to the use of LB for NGS at diagnosis in advanced NSCLC, including its advantages and limitations.

Clinical Impact of the Epithelial-Mesenchymal Transition in Lung Cancer as a Biomarker Assisting in Therapeutic Decisions

Lung cancer is one of the most common solid cancers and represents the leading cause of cancer death worldwide. Over the last decade, research on the epithelial-mesenchymal transition (EMT) in lung cancer has gained increasing attention. Here, we review clinical and histological features of non-small-cell lung cancer associated with EMT. We then aimed to establish potential clinical implications of EMT in current therapeutic options, including surgery, radiation, targeted therapy against oncogenic drivers, and immunotherapy.

Rare osteosarcoma cell subpopulation protein array and profiling using imaging mass cytometry and bioinformatics analysis

BACKGROUND

Single rare cell characterization represents a new scientific front in personalized therapy. Imaging mass cytometry (IMC) may be able to address all these questions by combining the power of MS-CyTOF and microscopy.

METHODS

We have investigated this IMC method using < 100 to up to 1000 cells from human sarcoma tumor cell lines by incorporating bioinformatics-based t-Distributed Stochastic Neighbor Embedding (t-SNE) analysis of highly multiplexed IMC imaging data. We tested this process on osteosarcoma cell lines TC71, OHS as well as osteosarcoma patient-derived xenograft (PDX) cell lines M31, M36, and M60. We also validated our analysis using sarcoma patient-derived CTCs.

RESULTS

We successfully identified heterogeneity within individual tumor cell lines, the same PDX cells, and the CTCs from the same patient by detecting multiple protein targets and protein localization. Overall, these data reveal that our t-SNE-based approach can not only identify rare cells within the same cell line or cell population, but also discriminate amongst varied groups to detect similarities and differences.

CONCLUSIONS

This method helps us make greater inroads towards generating patient-specific CTC fingerprinting that could provide an accurate tumor status from a minimally-invasive liquid biopsy.

Microfluidics and Nanomaterial-based Technologies for Circulating Tumor Cell Isolation and Detection

Cancer has been one of the leading causes of death globally, with metastases and recurrences contributing to this result. The detection of circulating tumor cells (CTCs), which have been implicated as a major population of cells that is responsible for seeding and migration of tumor sites, could contribute to early detection of metastasis and recurrences, consequently increasing the chances of cure. This review article focuses on the current progress in microfluidics technology in CTCs diagnostics, extending to the use of nanomaterials and surface modification techniques for diagnostic applications, with an emphasis on the importance of integrating microchannels, nanomaterials, and surface modification techniques in the isolating and detecting of CTCs.

Perspectives of the Application of Liquid Biopsy in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common gastrointestinal tumors and the second leading cause of cancer death worldwide. Since traditional biopsies are invasive and do not reflect tumor heterogeneity or monitor the dynamic progression of tumors, there is an urgent need for new noninvasive methods that can supplement and improve the current management strategies of CRC. Blood-based liquid biopsies are a promising noninvasive biomarker that can detect disease early, assist in staging, monitor treatment responses, and predict relapse and metastasis. Over time, an increasing number of experiments have indicated the clinical utility of liquid biopsies in CRC. In this review, we mainly focus on the development of circulating tumor cells and circulating tumor DNA as key components of liquid biopsies in CRC and introduce the potential of exosomal microRNAs as emerging liquid biopsy markers in clinical application for CRC.

Optical and electrochemical-based nano-aptasensing approaches for the detection of circulating tumor cells (CTCs)

More recently, detection of circulating tumor cells (CTCs) has been considered as an appealing prognostic and diagnostic approach for cancer patients. CTCs as a type of tumor-derived cells are secreted by the tumor and released into the blood circulation. Since the migration of CTCs is an early event in cancer progression, patients who still have tumor-free lymph nodes have to be well examined for the CTCs presence in their blood circulation. Nowadays, there is a broad range of detection methods available to identify CTCs. As artificial RNA oligonucleotides or single-stranded DNA with receptor and catalytic characteristics, aptamers have been standing out, owing to their target-induced conformational modifications, elevated stability, and target specificity to be implemented in biosensing techniques. To date, several sensitivity-enhancement methods alongside smart nanomaterials have been used for the creation of new aptasensors to address the limit of detection (LOD), and improve the sensitivity of numerous analyte identification methods. The present review article supports a focused overview of the recent studies in the identification and quantitative determination of CTCs by aptamer-based biosensors and nanobiosensors.

Circulating Tumor Cells and Cell-Free DNA in Pancreatic Ductal Adenocarcinoma

Pancreatic cancer is detected late in the disease process and has an extremely poor prognosis. A blood-based biomarker that can enable early detection of disease, monitor response to treatment, and potentially allow for personalized treatment would be of great benefit. This review analyzes the literature regarding two potential biomarkers, circulating tumor cells (CTCs) and cell-free DNA (cfDNA), with regard to pancreatic ductal adenocarcinoma. The origin of CTCs and the methods of detection are discussed and a decade of research examining CTCs in pancreatic cancer is summarized, including both levels of CTCs and analyzing their molecular characteristics and how they may affect survival in both advanced and early disease and allow for treatment monitoring. The origin of cfDNA is discussed, and the literature over the past 15 years is summarized. This includes analyzing cfDNA for genetic mutations and methylation abnormalities, which have the potential to be used for the detection and prognosis of pancreatic ductal adenocarcinoma. However, the research certainly remains in the experimental stage, warranting future large trials in these areas.

Liquid biopsy for the detection and management of surgically resectable tumors

BACKGROUND

Traditional biopsies have numerous limitations in the developing era of precision medicine, with cancer treatment that relies on biomarkers to guide therapy. Tumor heterogeneity raises the potential for sampling error with the use of traditional biopsy of the primary tumor. Moreover, tumors continuously evolve as new clones arise in the natural course of the disease and under the pressure of treatment. Since traditional biopsy is invasive, it is neither feasible nor practical to perform serial biopsies to guide treatment in real time.

PURPOSE

The current manuscript will review the most commonly used types of liquid biopsy and how these apply to surgical patients in terms of diagnosis, prediction of outcome, and guiding therapy.

CONCLUSIONS

Liquid biopsy has the potential to overcome many of the limitations of traditional biopsy as a highly tailored, minimally invasive, and cost-effective method to screen and monitor response to treatment. However, many challenges still need to be overcome before liquid biopsy becomes a reliable and widely available option.

The expression of EpCAM in extramammary Paget's disease

Extramammary Paget's disease (EMPD) is a rare skin malignant tumor. The prognosis of EMPD with distant metastasis is poor, however an effective therapy has not yet established. Recently, EpCAM (epithelial cell adhesion molecule, CD326) has attracted attention as both prognostic marker and therapeutic target in several cancers. Besides, EpCAM is an important surface marker of circulating tumor cell (CTC) in the collection of CTC. Thus, the purpose of our study was to examine the expression levels of EpCAM and evaluate the correlation between its intensity of EpCAM and the clinical characteristics of EMPD. The expression of EpCAM in EMPD was examined using immunohistochemistry. Skin samples were obtained from 32 patients with EMPD. We found that almost all EMPD tissues (90.6%, 29/32) were positive for EpCAM. Furthermore, the staining intensity of EpCAM protein negatively correlated with the presence of distant metastasis. Overexpression of EpCAM in EMPD cells suggests that EpCAM may be a novel therapeutic target and the research of CTC may be newly developed in EMPD. Based on these findings, EpCAM may be a meaningful molecule in EMPD.

Understanding tumor ecosystems by single-cell sequencing: promises and limitations

Cellular heterogeneity within and across tumors has been a major obstacle in understanding and treating cancer, and the complex heterogeneity is masked if bulk tumor tissues are used for analysis. The advent of rapidly developing single-cell sequencing technologies, which include methods related to single-cell genome, epigenome, transcriptome, and multi-omics sequencing, have been applied to cancer research and led to exciting new findings in the fields of cancer evolution, metastasis, resistance to therapy, and tumor microenvironment. In this review, we discuss recent advances and limitations of these new technologies and their potential applications in cancer studies.

Matrix Metalloproteinase Inhibitors in Cancer Therapy: Turning Past Failures Into Future Successes

The matrix metalloproteinases (MMP) are a family of proteolytic enzymes that degrade multiple components of the extracellular matrix. A large body of experimental and clinical evidence has implicated MMPs in tumor invasion, neoangiogenesis, and metastasis, and therefore they represent ideal pharmacologic targets for cancer therapy. From the 1990s to early 2000s, synthetic inhibitors of MMPs (MMPI) were studied in various cancer types. Unexpectedly, despite strongly promising preclinical data, all trials were unsuccessful in reducing tumor burden or improving overall survival; in addition, MMPIs had unforeseen, severe side effects. Two main reasons can explain the failure of MMPIs in clinical trials. It has now become apparent that some MMPs have antitumor effects; therefore, the broad-spectrum MMPIs used in the initial trials might block these MMPs and result in tumor progression. In addition, although MMPs are involved in the early stages of tumor progression, MMPIs were tested in patients with advanced disease, beyond the stage when these compounds could be effective. As more specific MMPIs are now available, MMP targeting could be reconsidered for cancer therapy; however, new trials should be designed to test their antimetastatic properties in early-stage tumors, and endpoints should focus on parameters other than decreasing metastatic tumor burden. Mol Cancer Ther; 17(6); 1147-55. ©2018 AACR.

Liquid Biopsy in Clinical Management of Breast, Lung, and Colorectal Cancer

Examination of tumor molecular characteristics by liquid biopsy is likely to greatly influence personalized cancer patient management. Analysis of circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), and tumor-derived exosomes, all collectively referred to as “liquid biopsies,” are not only a modality to monitor treatment efficacy, disease progression, and emerging therapy resistance mechanisms, but they also assess tumor heterogeneity and evolution in real time. We review the literature concerning the examination of ctDNA and CTC in a diagnostic setting, evaluating their prognostic, predictive, and monitoring capabilities. We discuss the advantages and limitations of various leading ctDNA/CTC analysis technologies. Finally, guided by the results of clinical trials, we discuss the readiness of cell-free DNA and CTC as routine biomarkers in the context of various common types of neoplastic disease. At this moment, one cannot conclude whether or not liquid biopsy will become a mainstay in oncology practice.

Integrating pharmacogenetic testing into primary care

Introduction

Pharmacogenetic (PGx) testing has greatly expanded due to enhanced understanding of the role of genes in drug response and advances in DNA-based testing technology development. As many primary care visits result in a prescription, the use of PGx testing may be particularly beneficial in this setting. However, integration of PGx testing may be limited as no uniform approach to delivery of tests has been established and providers are ill-prepared to integrate PGx testing into routine care.

Areas covered

In this paper, the readiness of primary care practitioners are reviewed as well as strategies to address these barriers based on published research and ongoing activities on education and implementation of PGx testing.

Expert Commentary

Widespread integration of PGx testing will warrant continued education and point-of-care decisional support. Primary care providers may also benefit from consultation services or team-based care with laboratory medicine specialists, pharmacists, and genetic counselors.