Circulating Epithelial Cells in Patients with Pancreatic Lesions: Clinical and Pathologic Findings

How much do we know about the metastatic process?

Cancer cells can leave their primary sites and travel through the circulation to distant sites, where they lodge as disseminated cancer cells (DCCs), even during the early and asymptomatic stages of tumor progression. In experimental models and clinical samples, DCCs can be detected in a non-proliferative state, defined as cellular dormancy. This state can persist for extended periods until DCCs reawaken, usually in response to niche-derived reactivation signals. Therefore, their clinical detection in sites like lymph nodes and bone marrow is linked to poor survival. Current cancer therapy designs are based on the biology of the primary tumor and do not target the biology of the dormant DCC population and thus fail to eradicate the initial or subsequent waves of metastasis. In this brief review, we discuss the current methods for detecting DCCs and highlight new strategies that aim to target DCCs that constitute minimal residual disease to reduce or prevent metastasis formation. Furthermore, we present current evidence on the relevance of DCCs derived from early stages of tumor progression in metastatic disease and describe the animal models available for their study. We also discuss our current understanding of the dissemination mechanisms utilized by genetically less- and more-advanced cancer cells, which include the functional analysis of intermediate or hybrid states of epithelial-mesenchymal transition (EMT). Finally, we raise some intriguing questions regarding the clinical impact of studying the crosstalk between evolutionary waves of DCCs and the initiation of metastatic disease.

A FACS-based novel isolation technique identifies heterogeneous CTCs in oral squamous cell carcinoma

Purpose

Isolating circulating tumour cells (CTCs) from the blood is challenging due to their low abundance and heterogeneity. Limitations of conventional CTC detection methods highlight the need for improved strategies to detect and isolate CTCs. Currently, the Food and Drug Administration (FDA)-approved CellSearch™ and other RUO techniques are not available in India. Therefore, we wanted to develop a flexible CTC detection/isolation technique that addresses the limitation(s) of currently available techniques and is suitable for various downstream applications.

Methods

We developed a novel, efficient, user-friendly CTC isolation strategy combining density gradient centrifugation and immuno-magnetic hematogenous cell depletion with fluorescence-activated cell sorting (FACS)-based positive selection using multiple CTC-specific cell-surface markers. For FACS, a stringent gating strategy was optimised to exclude debris and doublets by side scatter/forward scatter (SSC/FSC) discriminator, remove dead cells by 4',6-diamidino-2-phenylindole (DAPI) staining, and eliminate non-specific fluorescence using a "dump" channel. APC-labelled anti-CD45mAB was used to gate remaining hematogenous cells, while multiple epithelial markers (EpCAM, EGFR, and Pan-Cytokeratin) and an epithelial-mesenchymal transition (EMT) marker (Vimentin) labelled with fluorescein isothiocyanate (FITC) were used to sort cancer cells. The technique was initially developed by spiking Cal 27 cancer cells into the blood of healthy donors and then validated in 95 biopsy-proven oral squamous cell carcinoma (OSCC) patients. CTCs isolated from patients were reconfirmed by Giemsa staining, immuno-staining, and whole transcriptome amplification (WTA), followed by qRT-PCR. In vitro culture and RNA sequencing (RNA-Seq) were also performed to confirm their suitability for various downstream applications.

Results

The mean detection efficiency for the Cal 27 tongue cancer cells spiked in the whole blood of healthy donors was 32.82% ± 12.71%. While ~75% of our patients (71/95) had detectable CTCs, the CTC positivity was independent of the TNM staging. The isolated potential cancer cells from OSCC patients were heterogeneous in size. They expressed different CTC-specific markers in various combinations as identified by qRT-PCR after WTA in different patients. Isolated CTCs were also found to be suitable for downstream applications like short-term CTC culture and RNA-Seq.

Conclusion

We developed a sensitive, specific, flexible, and affordable CTC detection/isolation technique, which is scalable to larger patient cohorts, provides a snapshot of CTC heterogeneity, isolates live CTCs ready for downstream molecular analysis, and, most importantly, is suitable for developing countries.

Clinical Application of Liquid Biopsy in Pancreatic Cancer: A Narrative Review

Pancreatic ductal adenocarcinoma contributes significantly to global cancer-related deaths, featuring only a 10% survival rate over five years. The quest for novel tumor markers is critical to facilitate early diagnosis and tailor treatment strategies for this disease, which is key to improving patient outcomes. In pancreatic ductal adenocarcinoma, these markers have been demonstrated to play a crucial role in early identification, continuous monitoring, and prediction of its prognosis and have led to better patient outcomes. Nowadays, biopsy specimens serve to ascertain diagnosis and determine tumor type. However, liquid biopsies present distinct advantages over conventional biopsy techniques. They offer a noninvasive, easily administered procedure, delivering insights into the tumor's status and facilitating real-time monitoring. Liquid biopsies encompass a variety of elements, such as circulating tumor cells, circulating tumor DNA, extracellular vesicles, microRNAs, circulating RNA, tumor platelets, and tumor endothelial cells. This review aims to provide an overview of the clinical applications of liquid biopsy as a technique in the management of pancreatic cancer.

Liquid biopsy techniques and pancreatic cancer: diagnosis, monitoring, and evaluation

Pancreatic cancer (PC) is one of the most common malignancies. Surgical resection is a potential curative approach for PC, but most patients are unsuitable for operations when at the time of diagnosis. Even with surgery, some patients may still experience tumour metastasis during the operation or shortly after surgery, as precise prognosis evaluation is not always possible. If patients miss the opportunity for surgery and resort to chemotherapy, they may face the challenging issue of chemotherapy resistance. In recent years, liquid biopsy has shown promising prospects in disease diagnosis, treatment monitoring, and prognosis assessment. As a noninvasive detection method, liquid biopsy offers advantages over traditional diagnostic procedures, such as tissue biopsy, in terms of both cost-effectiveness and convenience. The information provided by liquid biopsy helps clinical practitioners understand the molecular mechanisms underlying tumour occurrence and development, enabling the formulation of more precise and personalized treatment decisions for each patient. This review introduces molecular biomarkers and detection methods in liquid biopsy for PC, including circulating tumour cells (CTCs), circulating tumour DNA (ctDNA), noncoding RNAs (ncRNAs), and extracellular vesicles (EVs) or exosomes. Additionally, we summarize the applications of liquid biopsy in the early diagnosis, treatment response, resistance assessment, and prognostic evaluation of PC.

Value of peripheral blood circulating tumor cell detection in the diagnosis of thoracic diseases and the prediction of severity

Circulating tumor cell (CTC) detection, as a noninvasive liquid biopsy method, has been used in the diagnosis, prognostic indication, and monitoring of a variety of cancers. In this study, we aimed to investigate whether CTC detection could be used in the early diagnosis and prediction of severity of thoracic diseases. We enrolled 168 thoracic disease patients, all of whom underwent pathological biopsy. Carcinoembryonic antigen (CEA) and neuron-specific enolase (NSE) measurement was also performed in 146 patients. There were 131 cases of malignant thoracic diseases and 37 cases of benign lesions. We detected CTCs in a 5 ml peripheral blood sample with the CTCBiopsy® system and analyzed the value of CTC count for predicting disease severity. Of 131 patients with a diagnosis of thoracic malignancy, CTCs were found in blood samples from 122 patients. However, only 2 out of 37 patients with benign thoracic disease had no detectable CTCs. There was no significant correlation between CTC count and benign and malignant lesions (P = 0.986). However, among 131 patients who had been diagnosed with malignant lesions, 33 had lymph node metastasis or distant metastasis. The presence of CTCs was significantly correlated with metastasis (P = 0.016 OR = 1.14). The area under the receiver operating characteristic (ROC) curve was 0.625 (95% confidence interval (CI), 0.519 to 0.730 P = 0.032). In addition, with stage IA1 as the cutoff, all patients were further divided into an early-stage group and a late-stage group. CTC count was significantly correlated with disease progression (P = 0.031 OR = 1.11), with an area under the curve (AUC) of 0.599 (95% CI, 0.506-0.692 P = 0.47). The sensitivity and specificity of CTC detection for the diagnosis of disease stage were 72.3% and 45.5%, respectively. In addition, the cutoff of 2.5 CTCs was the same when predicting disease metastasis and staging. Furthermore, the combination of CTC count, demographic characteristics and tumor markers had better predictive significance for disease staging. CTC count can effectively indicate the stages and metastasis of thoracic diseases, but it cannot differentiate benign and malignant diseases.

Advances in Liquid Biopsy Technology and Implications for Pancreatic Cancer

Pancreatic cancer is a highly aggressive malignancy with a climbing incidence. The majority of cases are detected late, with incurable locally advanced or metastatic disease. Even in individuals who undergo resection, recurrence is unfortunately very common. There is no universally accepted screening modality for the general population and diagnosis, evaluation of treatment response, and detection of recurrence relies primarily on the use of imaging. Identification of minimally invasive techniques to help diagnose, prognosticate, predict response or resistance to therapy, and detect recurrence are desperately needed. Liquid biopsies represent an emerging group of technologies which allow for non-invasive serial sampling of tumor material. Although not yet approved for routine use in pancreatic cancer, the increasing sensitivity and specificity of contemporary liquid biopsy platforms will likely change clinical practice in the near future. In this review, we discuss the recent technological advances in liquid biopsy, focusing on circulating tumor DNA, exosomes, microRNAs, and circulating tumor cells.

Comparative application of microfluidic systems in circulating tumor cells and extracellular vesicles isolation; a review

Cancer is a prevalent cause of mortality globally, where early diagnosis leads to a reduced death rate. Many researchers' common strategies are based on personalized diagnostic methods with rapid response and high accuracy. This technology was developed by applying liquid biopsy instead of tissue biopsies in the case of tumor cell analysis that facilitates point-of-care testing for cancer diagnosis and treatment. In recent years, significant progress in microfluidic technology led to the successful isolation, analysis, and monitoring of cancer biomarkers in body liquid biopsy with merits like high sensitivity and flexibility, low sample usage, cost effective, and the ability of automation. The most critical and informative markers in body liquid refer to circulating tumor cells (CTCs) and extracellular vesicles derived from tumors (EVs) that carry various biomarkers in their structure (DNAs, proteins, and RNAs) as compared to ctDNA. The released ctDNA has a low half-life and decreased sensitivity due to large amounts of nucleic acid in serum. This review intends to highlight different cancer screening tests with a particular focus on the details regarding the only FDA-approved and awaiting technologies for FDA clearance to isolate CTCs and EVs based on microfluidics systems.

EMT Molecular Signatures of Pancreatic Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NENs) are relatively rare neoplasms occurring predominantly in the gastrointestinal tract and pancreas. Their heterogeneity poses challenges for diagnosis and treatment. There is a paucity of markers for characterisation of NEN tumours. For routine diagnosis, immunohistochemistry of the NEN-specific markers CgA and synaptophysin and the proliferation marker Ki-67 are used. These parameters, however, are qualitative and lack the capacity to fully define the tumour phenotype. Molecules of epithelial–mesenchymal transition (EMT) are potential candidates for improved tumour characterisation. Using qRT-PCR, we measured mRNA levels of 27 tumour markers, including 25 EMT-associated markers, in tumour tissue and matched non-tumour tissues for 13 patients with pancreatic NENs. Tissue from patients with three different grades of tumour had distinctly different mRNA profiles. Of the 25 EMT-associated markers analysed, 17 were higher in G3 tissue relative to matched non-tumour tissue, including CD14, CD24, CD31, CD44, CD45, CD56, CK6, CK7, CK13, CK20, NSE, CDX2, CgA, DAXX, PCNA, laminin and Ki-67. The differences in levels of seven EMT-associated markers, Ki-67, DAXX, CD24, CD44, vimentin, laminin and PDX1 plus CgA and NSE (neuroendocrine markers) enabled a distinct molecular signature for each tumour grade to be generated. EMT molecules differentially expressed in three tumour grades have potential for use in tumour stratification and prognostication and as therapeutic targets for treatment of neuroendocrine cancers, following validation with additional samples.

Exploring the Clinical Utility of Pancreatic Cancer Circulating Tumor Cells

Pancreatic ductal adenocarcinoma (PDAC) is the most frequent pancreatic cancer type, characterized by a dismal prognosis due to late diagnosis, frequent metastases, and limited therapeutic response to standard chemotherapy. Circulating tumor cells (CTCs) are a rare subset of tumor cells found in the blood of cancer patients. CTCs has the potential utility for screening, early and definitive diagnosis, prognostic and predictive assessment, and offers the potential for personalized management. However, a gold-standard CTC detection and enrichment method remains elusive, hindering comprehensive comparisons between studies. In this review, we summarize data regarding the utility of CTCs at different stages of PDAC from early to metastatic disease and discuss the molecular profiling and culture of CTCs. The characterization of CTCs brings us closer to defining the specific CTC subpopulation responsible for metastasis with the potential to uncover new therapies and more effective management options for PDAC.

Circulating Tumor Cells Enumeration from the Portal Vein for Risk Stratification in Early Pancreatic Cancer Patients

Simple Summary

Effective biomarkers are needed to enable personalized medicine for pancreatic cancer patients. This study analyzes the prognostic value, in early pancreatic cancer, of circulating tumor cells and clusters from the central venous catheter and portal blood. Circulating tumor cells were isolated using an immunomagnetic selection and were detected by microscopy using immunocytochemistry staining. In conclusion, the circulating tumor cell number in portal blood identifies a death risk in patients with early pancreatic cancer.

Abstract

Background. Effective biomarkers are needed to enable personalized medicine for pancreatic cancer patients. This study analyzes the prognostic value, in early pancreatic cancer, of single circulating tumor cell (CTC) and CTC clusters from the central venous catheter (CVC) and portal blood (PV). Methods. In total, 7 mL of PV and CVC blood from 35 patients with early pancreatic cancer were analyzed. CTC were isolated using a positive immunomagnetic selection. The detection and identification of CTC were performed by immunocytochemistry (ICC) and were analyzed by Epi-fluorescence and confocal microscopy. Results. CTC and the clusters were detected both in PV and CVC. In both samples, the CTC number per cluster was higher in patients with grade three or poorly differentiated tumors (G3) than in patients with well (G1) or moderately (G2) differentiated. Patients with fewer than 185 CTC in PV exhibited a longer OS than patients with more than 185 CTC (24.5 vs. 10.0 months; p = 0.018). Similarly, patients with fewer than 15 clusters in PV showed a longer OS than patients with more than 15 clusters (19 vs. 10 months; p = 0.004). These significant correlations were not observed in CVC analyses. Conclusions. CTC presence in PV could be an important prognostic factor to predict poor prognosis in early pancreatic cancer. In addition, the number of clustered-CTC correlate to a tumor negative differentiation degree and, therefore, could be used as a diagnostic biomarker for pancreatic cancer.

Molecular characterization of circulating tumor cells in pancreatic ductal adenocarcinoma: potential diagnostic and prognostic significance in clinical practice

BACKGROUND

The clinical value of heterogeneous sub-populations of circulating tumor cells (CTCs) in pancreatic ductal adenocarcinoma (PDAC) remains unclear.

METHODS

Peripheral blood samples were obtained from 67 PDAC patients. CTCs were isolated by employing CD45 negative enrichment technique and further characterized for epithelial to mesenchymal transition (EMT) or human equilibrative nucleoside transporter-1 (hENT-1). The relationships between CTCs sub-phenotypes with clinicopathological factors or post-operative recurrence in PDAC patients were analyzed.

RESULTS

EMT related CTCs could be isolated and identified from the 81% of patients (54/67), and both the total count (median: 5 vs. 17/mL, P<0.0001) and M-CTC percentage (median: 0.2 vs. 0.345, P=0.0244) of CTCs could differentiate local/regional with metastatic disease. Multivariate analysis showed that both AJCC stage (P=0.025) and M-CTC percentage (P=0.001) were independent prognostic indicators of recurrence free survival (RFS) in resected patients. Moreover, Kaplan-Meier survival analysis showed that M-CTC after 2 courses of chemotherapy was significantly associated with inferior RFS (49.5 weeks vs. undefined, P=0.0288). No significant correlation in hENT-1 expression was found between CTCs and matched tumor tissues, and further multivariate analysis suggested hENT-1 expression in CTCs as independent prognostic factor for RFS (P=0.016). Patients with low hENT-1 expression in CTCs had decreased RFS (32 weeks vs. undefined, P=0.0337).

CONCLUSIONS

CTCs could be the promising diagnostic biomarkers in PDAC patients, and phenotypic profiling of CTCs based on EMT or hENT-1 could help establish novel prognostic biomarkers in resected patients undergoing adjuvant gemcitabine-based chemotherapy.

KEYWORDS

Circulating tumor cells (CTCs); Pancreatic ductal adenocarcinoma (PDAC); Epithelial to mesenchymal transition (EMT); human equilibrative nucleoside transporter-1 (hENT-1).

Liquid Biopsy in Pancreatic Cancer: Are We Ready to Apply It in the Clinical Practice?

Pancreatic ductal adenocarcinoma (PDAC) exhibits the poorest prognosis of all solid tumors, with a 5-year survival of less than 10%. To improve the prognosis, it is necessary to advance in the development of tools that help us in the early diagnosis, treatment selection, disease monitoring, evaluation of the response and prognosis. Liquid biopsy (LB), in its different modalities, represents a particularly interesting tool for these purposes, since it is a minimally invasive and risk-free procedure that can detect both the presence of genetic material from the tumor and circulating tumor cells (CTCs) in the blood and therefore distantly reflect the global status of the disease. In this work we review the current status of the main LB modalities (ctDNA, exosomes, CTCs and cfRNAs) for detecting and monitoring PDAC.

Blood biomarkers for differential diagnosis and early detection of pancreatic cancer

Pancreatic cancer is currently the most lethal tumor entity and case numbers are rising. It will soon be the second most frequent cause of cancer-related death in the Western world. Mortality is close to incidence and patient survival after diagnosis stands at about five months. Blood-based diagnostics could be one crucial factor for improving this dismal situation and is at a stage that could make this possible. Here, we are reviewing the current state of affairs with its problems and promises, looking at various molecule types. Reported results are evaluated in the overall context. Also, we are proposing steps toward clinical utility that should advance the development toward clinical application by improving biomarker quality but also by defining distinct clinical objectives and the respective diagnostic accuracies required to achieve them. Many of the discussed points and conclusions are highly relevant to other solid tumors, too.

Detection of circulating tumour cells enables early recurrence prediction in hepatocellular carcinoma patients undergoing liver transplantation

BACKGROUND & AIMS

Liver transplantation (LTx) is one of the most effective treatments for hepatocellular carcinoma (HCC); however, tumour recurrence after LTx often leads to poor outcomes. This study investigated the value of circulating tumour cells (CTCs) as a predictor of recurrence following LTx in patients with HCC.

METHODS

This analysis included 193 patients with HCC who underwent LTx at our institute and accepted pre- and post-operative CTC detection; 38 were selected for serial CTC monitoring. The predictive value of CTCs for tumour recurrence in patients with HCC following LTx was evaluated. Single-cell whole genome sequencing was used to characterize CTCs.

RESULTS

Overall, the CTC burden decreased after LTx (P < .05). Post-operative CTC count ≥ 1 per 5 mL peripheral blood was identified as a potential biomarker for predicting tumour recurrence after LTx, especially in patients with no detectable CTCs prior to LTx and negative tumour serological biomarkers. The predictive value of post-operative CTC count ≥ 1 per 5 mL blood was retained in patients who did not meet the Milan criteria, University of California San Francisco (UCSF) criteria, or Fudan criteria (all P < .05). Furthermore, post-operative serial CTC detection may be useful in post-surgical surveillance for HCC recurrence.

CONCLUSIONS

CTCs may be a useful biomarker to evaluate recurrence risk following LTx in patients with HCC. Evaluation based on CTC detection may enhance the post-transplant management of HCC, and improve the therapeutic efficacy of LTx.

Detection of Circulating Tumor Cells in Resectable Pancreatic Ductal Adenocarcinoma: A Prospective Evaluation as a Prognostic Marker

Circulating tumor cells (CTCs) are useful biomarkers of many solid tumors, but are infrequently detected in early stage pancreatic ductal adenocarcinomas (PDACs). The first drainage of pancreatic venous blood flow come to portal vein and pass through the liver, and they finally go out for peripheral blood. We thought that comparing CTCs from portal vein and peripheral blood could enable us to understand the clinical meaning of CTCs from each different site in PDACs. Therefore, we aimed to determine 1) whether CTCs could be reliably identified in early stages (operable) of PDACs, 2) if there are any differences in the detected number of CTC in portal vein blood and peripheral blood, and 3) whether CTCs can be sensitive biomarkers for the prognosis of resectable PDAC patients. Newly diagnosed PDAC patients who underwent operation with curative intention between 2013 and 2015 were prospectively enrolled. Blood draws from portal and peripheral vein ran through the microfabricated porous filter, and anti-epithelial cell adhesion molecule (EpCAM) and anti-Plectin-1 antibodies were used for CTC identification. Baseline clinical characteristics, tumor characteristics, treatment, and clinical outcomes were assessed. The clinical stages of the 32 enrolled patients were as follows: IA/IB 1 (3.1%); IIA 9 (28.1%); IIB 17 (53.1%); III 5 (15.6%). Twenty-seven patients (84.4%) received R0 resection, while five patients (15.6%) received R1 resection. EpCAM+ CTCs were detected in 20 portal blood (62.5%) and 22 peripheral blood (68.8%). Plectin-1+ CTCs were identified in 14 portal blood (43.8%) and 16 peripheral blood (50%). Plectin-1-expressing CTCs were picked from CTC platform (microfabricated porous filter) and we could find out all KRAS mutation. Patients with detectable EpCAM+ CTC less than one in peripheral blood showed longer overall survival (OS) compared to patients with detectable CTCs more than one (35.5 months vs. 16.0 months). EpCAM and Plectin-1 successfully identified CTCs at the early stage of PDACs. Also, the number of CTCs could be a prognostic marker for survival in resectable PDACs.

The Potential Role of Liquid Biopsies in Advancing the Understanding of Neuroendocrine Neoplasms

Tumour tissue as a source for molecular profiling and for in vivo models has limitations (e.g., difficult access, limited availability, single time point, potential heterogeneity between primary and metastatic sites). Conversely, liquid biopsies provide an easily accessible approach, enabling timely and longitudinal interrogation of the tumour molecular makeup, with increased ability to capture spatial and temporal intra-tumour heterogeneity compared to tumour tissue. Blood-borne biomarker assays (e.g., circulating tumour cells (CTCs), circulating free/tumour DNA (cf/ctDNA)) pose unique opportunities for aiding in the molecular characterisation and phenotypic subtyping of neuroendocrine neoplasms and will be discussed in this article.

Circulating tumour cells in pancreatic cancer: A systematic review and meta-analysis of clinicopathological implications

BACKGROUND

The detection and quantification of circulating tumour cells (CTCs) in pancreatic cancer (PC) has the potential to provide prognostic information. The aim of this review was to provide an overview of the literature surrounding CTCs in PC.

METHODS

A systematic literature review on CTCs in PC between 2005-2020 was performed. Data based on peripheral vein samples were used to determine the positivity rate of CTCs, their prognostic significance and their relative numbers compared to portal vein (PV) samples.

RESULTS

The overall CTC detection rate in forty-four articles was 65% (95%CI: 55-75%). Detection rate for CellSearch was 26% (95%CI: 14-38%), which was lower than for both filtration and microfluidic techniques. In nine studies with >50 patients, overall survival was worse with CTC positivity (HR 1.82; 95%CI: 1.61-2.05). Five of seven studies which described PV CTC collection provided patient-level data. PV CTC yield was 7.7-fold (95%CI 1.35-43.9) that of peripheral blood.

CONCLUSIONS

CTCs were detected in the peripheral circulation of most patients with PC and may be related to prognosis and disease stage. PV blood contains more CTCs than peripheral blood sampling. This review points to the maturation of techniques of CTC enrichment, and its evidence base for eventual clinical deployment.

Tumor Hypoxia and Circulating Tumor Cells

Circulating tumor cells (CTCs) are a rare tumor cell subpopulation induced and selected by the tumor microenvironment's extreme conditions. Under hypoxia and starvation, these aggressive and invasive cells are able to invade the lymphatic and circulatory systems. Escaping from the primary tumor, CTCs enter into the bloodstream to form metastatic deposits or re-establish themselves in cancer's primary site. Although radiotherapy is widely used to cure solid malignancies, it can promote metastasis. Radiation can disrupt the primary tumor vasculature, increasing the dissemination of CTCs. Radiation also induces epithelial-mesenchymal transition (EMT) and eliminates suppressive signaling, causing the proliferation of existent, but previously dormant, disseminated tumor cells (DTCs). In this review, we collect the results and evidence underlying the molecular mechanisms of CTCs and DTCs and the effects of radiation and hypoxia in developing these cells.

Pancreatic Ductal Adenocarcinoma (PDAC) Organoids: The Shining Light at the End of the Tunnel for Drug Response Prediction and Personalized Medicine

Simple Summary

Pancreatic ductal adenocarcinoma (PDAC) causes massive medical problems because of late diagnosis and limited responsiveness to standard chemotherapeutic treatments. This makes PDAC one of the major causes of death by cancer. To address this problem, novel tools for early diagnosis and therapy are needed. The recent development of PDAC organoids, which represent micro-scale mini-tumors, offers promising new options for personalized drug-testing based on primary PDAC patient material. This overview article summarizes and discusses the current state-of-the-art in exploiting the organoid technology to improve clinical management of PDAC.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) represents 90% of pancreatic malignancies. In contrast to many other tumor entities, the prognosis of PDAC has not significantly improved during the past thirty years. Patients are often diagnosed too late, leading to an overall five-year survival rate below 10%. More dramatically, PDAC cases are on the rise and it is expected to become the second leading cause of death by cancer in western countries by 2030. Currently, the use of gemcitabine/nab-paclitaxel or FOLFIRINOX remains the standard chemotherapy treatment but still with limited efficiency. There is an urgent need for the development of early diagnostic and therapeutic tools. To this point, in the past 5 years, organoid technology has emerged as a revolution in the field of PDAC personalized medicine. Here, we are reviewing and discussing the current technical and scientific knowledge on PDAC organoids, their future perspectives, and how they can represent a game change in the fight against PDAC by improving both diagnosis and treatment options.

The importance of circulating and disseminated tumor cells in pancreatic cancer

Pancreatic cancer is a lethal disease in a large part due to the systemic nature at the time of diagnosis. In those patients who undergo a potentially curative resection of pancreatic cancer, the overwhelming majority will have systemic relapse. Circulating tumor cells are an important mediator of the development of metastases. Circulating tumor cells have been identified in patients with clinically localized resectable pancreatic cancer and exist as several phenotypes. Mesenchymal and stem cell-like phenotypes of circulating tumor cells predict early recurrence and worse survival. This review focuses on the current understanding of circulating tumor cells in pancreatic cancer and how this information can be used in developing more effective therapy in the future.

Combined detection of aneuploid circulating tumor-derived endothelial cells and circulating tumor cells may improve diagnosis of early stage non-small-cell lung cancer

BACKGROUND

Many tumor-derived endothelial cells (TECs) are shed into the blood and turn into circulating TECs (CTECs). Rare circulating non-hematologic aneuploid cells contain CTCs and CTECs, which are biologically and functionally different from each other. CD31 is one of the most representative endothelial cell (EC) markers, yet CD31 alone is not sufficient to detect malignant CTECs due to the existence of abundant normal ECs in circulation. Aneuploidy of chromosome 8 (CEP8) is an important criterion for the identification of malignant cells. Combined in situ phenotypic and karyotypic characterization, which includes an examination of both protein expression and aneuploid chromosomes, has demonstrated its unique advantage for both effective distinguishing and comprehensive detection of CTCs and CTECs.

METHODS

A total of 98 subjects were recruited in the current study, including healthy donors and patients with benign disease and early-stage non-small-cell lung cancer (NSCLC). SE-iFISH was performed to quantitatively analyze diverse subtypes of aneuploid CD31⁺ CTECs and CD31^- CTCs classified upon the ploidy of chromosome 8 and tumor marker expression in the specimens collected from the recruited subjects.

RESULTS

CD31^- CTCs primarily consist of triploid CTCs with a small cell size (≤5 µm) and large hyperploid CTCs (≥ pentaploid), whereas CD31⁺ CTECs are mainly comprised of large hyperploid cells. Enumeration of the total numbers of both CTCs and CTECs might help identify malignant nodules with a high sensitivity, whereas quantification of tetraploid CTCs and CTECs specifically exhibited a high specificity for the identification of malignant nodules.

CONCLUSIONS

Combined detection of the specific subtypes of aneuploid CD31⁺ CTECs and CD31^- CTCs may help to effectively identify malignant nodules with a higher sensitivity and specificity in early stage NSCLC patients.

Pancreatic Cancer and Its Microenvironment-Recent Advances and Current Controversies

Pancreatic ductal adenocarcinoma (PDAC) causes annually well over 400,000 deaths world-wide and remains one of the major unresolved health problems. This exocrine pancreatic cancer originates from the mutated epithelial cells: acinar and ductal cells. However, the epithelia-derived cancer component forms only a relatively small fraction of the tumor mass. The majority of the tumor consists of acellular fibrous stroma and diverse populations of the non-neoplastic cancer-associated cells. Importantly, the tumor microenvironment is maintained by dynamic cell-cell and cell-matrix interactions. In this article, we aim to review the most common drivers of PDAC. Then we summarize the current knowledge on PDAC microenvironment, particularly in relation to pancreatic cancer therapy. The focus is placed on the acellular stroma as well as cell populations that inhabit the matrix. We also describe the altered metabolism of PDAC and characterize cellular signaling in this cancer.

Circulating tumor cells in peripheral blood of pancreatic cancer patients and their prognostic role: a systematic review and meta-analysis

BACKGROUND

It has been shown that circulating tumor cells in peripheral blood can be used to predict survival in patients with breast, prostate and other epithelial tumors. In the present study, we performed a meta-analysis to evaluate the prognostic role of circulating tumor cells (CTCs) in patients with pancreatic cancer.

METHODS

A systematic literature search of the databases was conducted from the inception to Jul 20, 2019. Relative risks (RRs) with 95% confidence intervals (CIs) were calculated under a fixed or random effect model.

RESULTS

A total of 19 studies with 1320 confirmed individuals were included. Our meta-analysis showed that patients in the CTC-positive group had a significantly shorter overall survival (OS) (RR = 0.47, 95%CI = 0.33-0.61, P < 0.001) and progression-free survival (PFS) (P = 0.003) than CTC-negative patients. Moreover, subgroup analysis by ethnicity indicated that CTC-positive patients had a significantly shorter OS in both Asian and Western populations. Further subgroup analysis by detection methods, treatments, and Tumor Node Metastasis (TNM) stages also indicated that CTC-positive patients were associated with significant decreases in both OS and PFS  in most subgroups.

CONCLUSION

Our meta-analysis indicates that CTC-positive patients have a worse OS and PFS than CTC-negative patients, which suggests that CTCs may act as predictive biomarkers for pancreatic cancer patients before treatment.

Multiple functions of microfluidic platforms: Characterization and applications in tissue engineering and diagnosis of cancer

Microfluidic system, or lab-on-a-chip, has grown explosively. This system has been used in research for the first time and then entered in the clinical section. Due to economic reasons, this technique has been used for screening of laboratory and clinical indices. The microfluidic system solves some difficulties accompanied by clinical and biological applications. In this review, the interpretation and analysis of some recent developments in microfluidic systems in biomedical applications with more emphasis on tissue engineering and cancer will be discussed. Moreover, we try to discuss the features and functions of microfluidic systems.

Circulating Tumor Cells in Pancreatic Cancer: Current Perspectives

Pancreatic cancer is the fourth leading cause of cancer-related death in the USA and Europe; early symptoms and screenings are lacking, and it is usually diagnosed late with a poor prognosis. Circulating tumor cells (CTCs) have been promising new biomarkers in solid tumors. In the last twenty years (1999-2019), 140 articles have contained the key words "Circulating tumor cells, pancreatic cancer, prognosis and diagnosis." Articles were evaluated for the use of CTCs as prognostic markers and their correlation to survival in pancreatic ductal adenocarcinoma (PDAC). In the final selected 17 articles, the CTC detection rate varied greatly between different enrichment methodologies and ranged from 11% to 92%; the majority of studies used the antigen-dependent CellSearch^© system for CTC detection. Fifteen of the reviewed studies showed a correlation between CTC presence and a worse overall survival. The heterogeneity of CTC-detection methods and the lack of uniform results hinder a comparison of the evaluated studies. However, CTCs can be detected in pancreatic cancer and harbor a hope to serve as an early detection tool. Larger studies are needed to corroborate CTCs as valid biomarkers in pancreatic cancer.

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.

[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.

Liquid biopsy in pancreatic ductal adenocarcinoma: current status of circulating tumor cells and circulating tumor DNA

Reliable biomarkers are required to evaluate and manage pancreatic ductal adenocarcinoma. Circulating tumor cells and circulating tumor DNA are shed into blood and can be relatively easily obtained from minimally invasive liquid biopsies for serial assays and characterization, thereby providing a unique potential for early diagnosis, forecasting disease prognosis, and monitoring of therapeutic response. In this review, we provide an overview of current technologies used to detect circulating tumor cells and circulating tumor DNA and describe recent advances regarding the multiple clinical applications of liquid biopsy in pancreatic ductal adenocarcinoma.

Sensitive and easy screening for circulating tumor cells by flow cytometry

Circulating Tumor Cells (CTCs) represent an easy, repeatable and representative access to information regarding solid tumors. However, their detection remains difficult because of their paucity, their short half-life, and the lack of reliable surface biomarkers. Flow cytometry (FC) is a fast, sensitive and affordable technique, ideal for rare cells detection. Adapted to CTCs detection (i.e. extremely rare cells), most FC-based techniques require a time-consuming pre-enrichment step, followed by a 2-hours staining procedure, impeding on the efficiency of CTCs detection. We overcame these caveats and reduced the procedure to less than one hour, with minimal manipulation. First, cells were simultaneously fixed, permeabilized, then stained. Second, using low-speed FC acquisition conditions and two discriminators (cell size and pan-cytokeratin expression), we suppressed the pre-enrichment step. Applied to blood from donors with or without known malignant diseases, this protocol ensures a high recovery of the cells of interest independently of their epithelial-mesenchymal plasticity and can predict which samples are derived from cancer donors. This proof-of-concept study lays the bases of a sensitive tool to detect CTCs from a small amount of blood upstream of in-depth analyses.

Technologies for circulating tumor cell separation from whole blood

The importance of early cancer diagnosis and improved cancer therapy has been clear for years and has initiated worldwide research towards new possibilities in the care strategy of patients with cancer using technological innovations. One of the key research fields involves the separation and detection of circulating tumor cells (CTC) because of their suggested important role in early cancer diagnosis and prognosis, namely, providing easy access by a liquid biopsy from blood to identify metastatic cells before clinically detectable metastasis occurs and to study the molecular and genetic profile of these metastatic cells. Provided the opportunity to further progress the development of technology for treating cancer, several CTC technologies have been proposed in recent years by various research groups and companies. Despite their potential role in cancer healthcare, CTC methods are currently mainly used for research purposes, and only a few methods have been accepted for clinical application because of the difficulties caused by CTC heterogeneity, CTC separation from the blood, and a lack of thorough clinical validation. Therefore, the standardization and clinical application of various developed CTC technologies remain important subsequent necessary steps. Because of their suggested future clinical benefits, we focus on describing technologies using whole blood samples without any pretreatment and discuss their advantages, use, and significance. Technologies using whole blood samples utilize size-based, immunoaffinity-based, and density-based methods or combinations of these methods as well as positive and negative enrichment during separation. Although current CTC technologies have not been truly implemented yet, they possess high potential as future clinical diagnostic techniques for the individualized therapy of patients with cancer. Thus, a detailed discussion of the clinical suitability of these new advanced technologies could help prepare clinicians for the future and can be a foundation for technologies that would be used to eliminate CTCs in vivo.

anti-EGFR capture mitigates EMT- and chemoresistance-associated heterogeneity in a resistance-profiling CTC platform

Capture and analysis of circulating tumor cells (CTCs) holds promise for diagnosing and guiding treatment of pancreatic cancer. To accurately monitor disease progression, capture platforms must be robust to processes that increase the phenotypic heterogeneity of CTCs. Most CTC-analysis technologies rely on the recognition of epithelial-specific markers for capture and identification, in particular the epithelial cell-adhesion molecule (EpCAM) and cytokeratin. As the epithelial-to-mesenchymal transition (EMT) and the acquisition of chemoresistance are both associated with loss of epithelial markers and characteristics, the effect of these processes on the expression of commonly used CTC markers, specifically EpCAM, EGFR and cytokeratin, requires further exploration. To determine this effect, we developed an in vitro model of EMT and acquired gemcitabine resistance in human pancreatic cancer cell lines. Using this model, we show that EMT-induction and acquired chemoresistance decrease EpCAM expression and microfluidic anti-EpCAM capture performance. Furthermore, we find that EGFR capture is more robust to these processes. By measuring the expression of known mediators of chemoresistance in captured cells using automated imaging and image processing, we demonstrate the ability to resistance-profile cells on-chip. We expect that this approach will allow for the development of improved non-invasive biomarkers of pancreatic cancer progression.

Liquid biopsies for management of pancreatic cancer

Pancreatic cancer is one of the main causes of cancer-related deaths worldwide. It is asymptomatic at an early stage, and most diagnosis occurs when the disease is already at a late stage, by which time the tumor is nonresectable. In order to increase the overall survival of patients with pancreatic cancer, as well as to decrease the cancer burden, it is necessary to perform early diagnosis, prognosis stratifications and cancer monitoring using accurate, minimally invasive, and cost-effective methods. Liquid biopsies seek to detect tumor-associated biomarkers in a variety of extractable body fluids and can help to monitor treatment response and disease progression, and even predict patient outcome. In patients with pancreatic cancer, tumor-derived materials, primarily circulating tumor DNA, circulating tumor cells and exosomes, are being studied for inclusion in the management of the disease. This review focuses on describing the biology of these biomarkers, methods for their enrichment and detection, as well as their potential for clinical application. Moreover, we discuss the future direction of liquid biopsies and introduce how they can be exploited toward point of care personalized medicine for the management of pancreatic cancer.

Circulating Tumor Cells for the Management of Renal Cell Carcinoma

Renal cell carcinoma is a highly malignant cancer that would benefit from non-invasive innovative markers providing early diagnosis and recurrence detection. Circulating tumor cells are a particularly promising marker of tumor invasion that could be used to improve the management of patients with RCC. However, the extensive genetic and immunophenotypic heterogeneity of cells from RCC and their trend to transition to the mesenchymal phenotype when they circulate in blood constitute a challenge for their sensitive and specific detection. This review analyzes published studies targeting CTC in patients with RCC, in the context of the biological, pathological, and molecular complexity of this particular cancer. Although further analytical and clinical studies are needed to pinpoint the most suitable approach for highly sensitive CTC detection in RCC patients, it is clear that this field can bring a relevant guide to clinicians and help to RCC patients. Furthermore, as described, a particular subtype of RCC-the ccRCC-can be used as a model to study the relationship between cytomorphological and genetic cellular markers of malignancy, an important issue for the study of CTC from any type of solid cancer.

The identification and isolation of CTCs: A biological Rubik's cube

Liquid biopsy represents an alternative to conventional biopsies for the evaluation of tumors mainly due to its easy sampling. One of the main applications is the enumeration of Circulating Tumor Cells (CTCs) to evaluate tumor progression or response to treatment. The analysis of the functional characteristics of CTCs could give us much more information about their role in order to establish a more personalized treatment for the patients. The major issue that has to be solved is the isolation of the CTC population. Multiple protocols have been developed, however none of them has demonstrated to be the definitive one. In fact, a combination of these techniques has often been performed in order to obtain a purer and viable population of CTCs. In this review we have summarized for the first time the different combinatorial approaches used in the last years to optimize the isolation of CTCs and their limitations.

A prospective study of endoscopic ultrasonography features, cyst fluid carcinoembryonic antigen, and fluid cytology for the differentiation of small pancreatic cystic neoplasms

Background and Objectives

With improvements in imaging technologies, pancreatic cystic lesions (PCLs) have been increasingly identified in recent years. However, the imaging modalities used to differentiate the categories of pancreatic cysts remain limited, which may cause confusion when planning treatment. Due to progress in endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) technology, auxiliary diagnosis by the detection of cystic fluid has become a recent trend.

Methods

From March 2015 to April 2016, 120 patients with PCLs were enrolled in this study. According to the results of EUS, cyst fluid carcinoembryonic antigen (CEA) analysis, and cystic fluid cytology, the patients were divided into two groups: a nonmucinous and a mucinous group. Of those, 61 patients who had undergone surgical resection were included in the analysis. The clinical features, biochemical and tumor markers of cyst fluid as well as the cytological test results of the patients were compared with histopathology results.

Results

A cyst size of 4.0 cm was used as the boundary value; a cyst ≤4.0 cm was defined as a small PCL. 87 (72.5%) lesions were ≤4.0 cm, and 33 (27.5%) lesions were >4.0 cm. Regarding the analysis of CEA and carbohydrate antigens 19-9 (CA19-9), significant differences were found between the nonmucinous and mucinous groups (P < 0.05) according to nonparametric independent samples tests. The EUS, cystic fluid CEA, and cystic fluid cytology results were compared with the tissue pathology findings using McNemar's test (P < 0.05) and showed a sensitivity of 90% and a specificity of 84%.

Conclusion

A diagnostic combination of EUS, cyst fluid CEA, and cystic fluid cytology could be used to differentiate small pancreatic cystic neoplasms. Cystic fluid cytology analysis is helpful for planning treatment for pancreatic cystic tumors that pose a surgical risk.

EpCAM-based Flow Cytometric Detection of Circulating Tumor Cells in Gallbladder Carcinoma Cases

Purpose:

Liquid biopsy has entered the arena of cancer diagnostics in the past decade and detection of circulating tumor cells (CTC) is one diagnostic component. CTCs in gallbladder cancer (GBC) have hitherto not been comprehensively analysed.

Methods and Results:

The current study focused on the diagnostic role of CTCs in 27 cases of treatment-naive GBC and 6 normal controls as well as 6 cases of cholecystitis. An EasySep kit featuring negative immunomagnetic bead separation and flow cytometric detection of EpCAM positive and CD45 negative cells revealed CTCs in 25 of the 27 cases. At a cut-off point of ≥1, the CTC count discriminated GBC from controls with a sensitivity, specificity and diagnostic accuracy of 92.6%, 91.7% and 92.3%, respectively. CTC levels in turn correlated significantly with clinico-pathological parameters of cases in terms of known prognostic indicators, with significant diagnostic potential at a cut-off point of >4, to discriminate disease stage I and II vs. III and IV GBC. With a cut-off of >3, the CTC count discriminated tumor stages I and II vs. III and IV and at >6 CTCs could discriminate metastatic vs. non metastatic GBCs with a sensitivity, specificity and diagnostic accuracy of 55. 6%, 100.0% and 85.2, respectively. A review of CTC in pancreatico-biliary malignancies is included.

Conclusion:

Detection and quantification of CTCs may serve as a non-invasive biomarker for GBC diagnosis in correlation with radiological studies.

Novel biomarkers and endoscopic techniques for diagnosing pancreaticobiliary malignancy

The UK incidence of pancreatic ductal adenocarcinoma is 9 per 100,000 population, and biliary tract cancer occurs at a rate of 1–2 per 100,000. The incidence of both cancers is increasing annually and these tumours continue to be diagnosed late and at an advanced stage, limiting options for curative treatment. Population-based screening programmes do not exist for these cancers, and diagnosis currently is dependent on symptom recognition, but often symptoms are not present until the disease is advanced. Recently, a number of promising blood and urine biomarkers have been described for pancreaticobiliary malignancy and are summarised in this review. Novel endoscopic techniques such as single-operator cholangioscopy and confocal endomicroscopy have been used in some centres to enhance standard endoscopic diagnostic techniques and are also evaluated in this review.

Circulating Epithelial Cells in Intraductal Papillary Mucinous Neoplasms and Cystic Pancreatic Lesions

OBJECTIVES

Circulating epithelial cells (CECs) are identified in the blood of patients with intraductal papillary mucinous neoplasms (IPMNs) despite the absence of malignancy. We assessed the blood of patients undergoing resection for IPMN or other benign pancreatic lesions for CECs.

METHODS

Peripheral blood was collected from 26 patients prior to pancreatic resection and filtered by the ISET (Isolation by Size of Epithelial Tumor Cells) method. Circulating epithelial cells were identified with antibodies to cytokeratin and Pdx1 (pancreas and duodenal homeobox protein 1), a pancreas marker.

RESULTS

Nineteen patients underwent resection of an IPMN without associated malignancy. Eleven patients (58%) had cytokeratin-positive CECs. Circulating epithelial cells were significantly more likely to be found in patients with IPMNs with high-grade dysplasia (P = 0.04). In addition, 10 of the 11 patients with cytokeratin-positive CECs also had separate populations of cytokeratin-positive, Pdx1-positive CECs, suggesting a pancreatic source. Dual-staining CECs were more frequently found in patients with high-grade dysplasia (P = 0.04). Patients with IPMNs were significantly more likely to have pan-cytokeratin CECs in the blood compared with those without IPMNs (P = 0.01).

CONCLUSIONS

Circulating epithelial cells staining with potential pancreas-specific markers have been found in patients with IPMNs, even without malignancy. Circulating epithelial cells may help to differentiate patients with high-grade IPMN from lower grades of dysplasia and other pancreatic cysts.

Circulating tumor cells and microemboli can differentiate malignant and benign pulmonary lesions

The presence of circulating tumor cells (CTC) or microemboli (CTM) in the peripheral blood can theoretically anticipate malignancy of solid lesions in a variety of organs. We aimed to preliminarily assess this capability in patients with pulmonary lesions of suspected malignant nature.

We used a cell-size filtration method (ScreenCell) and cytomorphometric criteria to detect CTC/CTM in a 3 mL sample of peripheral blood that was taken just before diagnostic percutaneous CT-guided fine needle aspiration (FNA) or core biopsy of the suspicious lung lesion.

At least one CTC/CTM was found in 47 of 67 (70%) patients with final diagnoses of lung malignancy and in none of 8 patients with benign pulmonary nodules. In particular they were detected in 38 (69%) of 55 primary lung cancers and in 9 (75%) of 12 lung metastases from extra-pulmonary cancers. Sensitivity of CTC/CTM presence for malignancy was 70.1% (95%CI: 56.9-83.1%), specificity 100%, positive predictive value 100% and negative predictive value 28.6% (95%CI: 11.9-45.3%). Remarkably, the presence of CTC/CTM anticipated the diagnosis of primary lung cancer in 3 of 5 patients with non-diagnostic or inconclusive results of FNA or core biopsy, whereas CTC/CTM were not observed in 1 patient with sarcoidosis and 1 with amarthocondroma.

These results suggest that presently, due to the low sensitivity, the search of CTC/CTM cannot replace CT guided percutaneous FNA or core biopsy in the diagnostic work-up of patients with suspicious malignant lung lesions. However, the high specificity may as yet indicate a role in cases with non-diagnostic or inconclusive FNA or core biopsy results that warrants to be further investigated.

Pancreatic cancer: Circulating Tumor Cells and Primary Tumors show Heterogeneous KRAS Mutations

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease. Circulating tumor cells (CTC) in the blood are hypothesized as the means of systemic tumor spread. Blood obtained from healthy donors and patients with PDAC was therefore subject to size-based CTC-isolation. We additionally compared Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations in pancreatic CTC and corresponding tumors, and evaluated their significance as prognostic markers. Samples from 68 individuals (58 PDAC patients, 10 healthy donors) were analyzed; CTCs were present in patients with UICC stage IA-IV tumors and none of the controls (p < 0.001). Patients with >3 CTC/ml had a trend for worse median overall survival (OS) than patients with 0.3–3 CTC/ml (P = 0.12). Surprisingly, CTCs harbored various KRAS mutations in codon 12 and 13. Patients with a KRAS^G12V mutation in their CTC (n = 14) had a trend to better median OS (24.5 months) compared to patients with other (10 months), or no detectable KRAS mutations (8 months; P = 0.04). KRAS mutations in CTC and corresponding tumor were discordant in 11 of 26 “tumor-CTC-pairs” (42%), while 15 (58%) had a matching mutation; survival was similar in both groups (P = 0.36). Genetic characterization, including mutations such as KRAS, may prove useful for prognosis and understanding of tumor biology.

Cytologic characteristics of circulating epithelioid cells in pancreatic disease

BACKGROUND

Circulating epithelioid cells (CECs), also known as circulating tumor, circulating cancer, circulating epithelial, or circulating nonhematologic cells, are a prognostic factor in various malignancies that can be isolated via various protocols. In the current study, the authors analyzed the cytomorphologic characteristics of CECs isolated by size in a cohort of patients with benign and malignant pancreatic diseases to determine whether cytomorphological features could predict CEC origin.

METHODS

Blood samples were collected from 9 healthy controls and 171 patients with pancreatic disease who were presenting for surgical evaluation before treatment. Blood was processed with the ScreenCell size-based filtration device. Evaluable CECs were analyzed in a blinded fashion for cytomorphologic characteristics, including cellularity; nucleoli; nuclear size, irregularity, variability, and hyperchromasia; and nuclear-to-cytoplasmic ratio. Statistical differences between variables were analyzed via the Fisher exact test.

RESULTS

No CECs were identified among the 9 normal healthy controls. Of the 115 patients with CECs (positive or suspicious for), 25 had nonmalignant disease and 90 had malignancy. There were no significant differences in any of the cytologic criteria noted between groups divided by benign versus malignant, neoplastic versus nonneoplastic, or pancreatic ductal adenocarcinoma versus neuroendocrine tumor.

CONCLUSIONS

CECs were observed in patients with malignant and nonmalignant pancreatic disease, but not in healthy controls. There were no morphologic differences observed between cells from different pancreatic diseases, suggesting that numerous conditions may be associated with CECs in the circulation and that care must be taken not to overinterpret cells identified by cytomorphology as indicative of circulating tumor cells of pancreatic cancer. Additional studies are required to determine the origin and clinical significance of these cells. Cancer Cytopathol 2017;125:332-340. © 2017 American Cancer Society.

Clinical Applications of Circulating Tumor Cells in Pharmacotherapy: Challenges and Perspectives

Screening for circulating tumor cells (CTCs) has been identified as one approach to ultrasensitive liquid biopsy in real-time monitoring of cancer patients. The detection of CTCs in peripheral blood from cancer patients is promising as a diagnostic tool; however, the application of CTCs in therapeutic treatment still faces serious challenges with respect to specificity and sensitivity. Here, we review the significant roles of CTCs in metastasis and the strengths and weaknesses of the currently available methods for CTC detection and characterization. Moreover, we discuss the clinical application of CTCs as markers for patient prognosis, and we specifically focus on the application of CTCs as indicators in cancer pharmacotherapy. Characterization of the detected CTCs will provide new biologic perspectives and clinical applications for the treatment of cancer patients with metastasis.

Biomarkers in pancreatic adenocarcinoma: current perspectives

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis, with a 5-year survival rate of 7.7%. Most patients are diagnosed at an advanced stage not amenable to potentially curative resection. A substantial portion of this review is dedicated to reviewing the current literature on carbohydrate antigen (CA 19-9), which is currently the only guideline-recommended biomarker for PDAC. It provides valuable prognostic information, can predict resectability, and is useful in decision making about neoadjuvant therapy. We also discuss carcinoembryonic antigen (CEA), CA 125, serum biomarker panels, circulating tumor cells, and cell-free nucleic acids. Although many biomarkers have now been studied in relation to PDAC, significant work still needs to be done to validate their usefulness in the early detection of PDAC and management of patients with PDAC.

Circulating Tumor Cells and Circulating Tumor DNA Provide New Insights into Pancreatic Cancer

Pancreatic cancer has a rather dismal prognosis mainly due to high malignance of tumor biology. Up to now, the relevant researches on pancreatic cancer lag behind seriously partly due to the obstacles for tissue biopsy, which handicaps the understanding of molecular and genetic features of pancreatic cancer. In the last two decades, liquid biopsy, including circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA), is promising to provide new insights into the biological and clinical characteristics of malignant tumors. Both CTCs and ctDNA provide an opportunity for studying tumor heterogeneity, drug resistance, and metastatic mechanism for pancreatic cancer. Furthermore, they can also play important roles in detecting early-stage tumors, providing prognostic information, monitoring tumor progression and guiding treatment regimens. In this review, we will introduce the latest findings on biological features and clinical applications of both CTCs and ctDNA in pancreatic cancer. In a word, CTCs and ctDNA are promising to promote precision medicine in pancreatic cancer.

Label-free enumeration, collection and downstream cytological and cytogenetic analysis of circulating tumor cells

Circulating tumor cells (CTCs) have a great potential as indicators of metastatic disease that may help physicians improve cancer prognostication, treatment and patient outcomes. Heterogeneous marker expression as well as the complexity of current antibody-based isolation and analysis systems highlights the need for alternative methods. In this work, we use a microfluidic Vortex device that can selectively isolate potential tumor cells from blood independent of cell surface expression. This system was adapted to interface with three protein-marker-free analysis techniques: (i) an in-flow automated image processing system to enumerate cells released, (ii) cytological analysis using Papanicolaou (Pap) staining and (iii) fluorescence in situ hybridization (FISH) targeting the ALK rearrangement. In-flow counting enables a rapid assessment of the cancer-associated large circulating cells in a sample within minutes to determine whether standard downstream assays such as cytological and cytogenetic analyses that are more time consuming and costly are warranted. Using our platform integrated with these workflows, we analyzed 32 non-small cell lung cancer (NSCLC) and 22 breast cancer patient samples, yielding 60 to 100% of the cancer patients with a cell count over the healthy threshold, depending on the detection method used: respectively 77.8% for automated, 60–100% for cytology, and 80% for immunostaining based enumeration.