Perioperative cancer cell dissemination detected with a real-time RT-PCR assay for EpCAM is not associated with worse prognosis in pancreatic ductal adenocarcinoma

A Comprehensive Review of the Potential Role of Liquid Biopsy as a Diagnostic, Prognostic, and Predictive Biomarker in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma is one of the most lethal malignant diseases, with a mortality rate being close to incidence. Due to its heterogeneity and plasticity, as well as the lack of distinct symptoms in the early phases, it is very often diagnosed at an advanced stage, resulting in poor prognosis. Traditional tissue biopsies remain the gold standard for making a diagnosis, but have an obvious disadvantage in their inapplicability for frequent sampling. Blood-based biopsies represent a non-invasive method which potentially offers easy and repeated sampling, leading to the early detection and real-time monitoring of the disease and hopefully an accurate prognosis. Given the urgent need for a reliable biomarker that can estimate a patient's condition and response to an assigned treatment, blood-based biopsies are emerging as a potential new tool for improving patients' survival and surveillance. In this article, we discuss the current advances and challenges in using liquid biopsies for pancreatic cancer, focusing on circulating tumour DNA (ctDNA), extracellular vesicles (EVs), and circulating tumour cells (CTCs), and compare the performance and reliability of different biomarkers and combinations of biomarkers.

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.

Epithelial to Mesenchymal Transition as Mechanism of Progression of Pancreatic Cancer: From Mice to Men

Owed to its aggressive yet subtle nature, pancreatic cancer remains unnoticed till an advanced stage so that in most cases the diagnosis is made when the cancer has already spread to other organs with deadly efficiency. The progression from primary tumor to metastasis involves an intricate cascade of events comprising the pleiotropic process of epithelial to mesenchymal transition (EMT) facilitating cancer spread. The elucidation of this pivotal phenotypic change in cancer cell morphology, initially heretic, moved from basic studies dissecting the progression of pancreatic cancer in animal models to move towards human disease, although no clinical translation of the concept emerged yet. Despite this transition, a full-blown mesenchymal phenotype may not be accomplished; rather, the plasticity of the program and its dependency on heterotopic signals implies a series of fluctuating modifications of cancer cells encompassing mesenchymal and epithelial features. Despite the evidence supporting the activation of EMT and MET during cancer progression, our understanding of the relationship between tumor microenvironment and EMT is not yet mature for a clinical application. In this review, we attempt to resume the knowledge on EMT and pancreatic cancer, aiming to include the EMT among the hallmarks of cancer that could potentially modify our clinical thinking with the purpose of filling the gap between the results pursued in basic research by animal models and those achieved in translational research by surrogate biomarkers, as well as their application for prognostic and predictive purposes.

Folate receptor-positive circulating tumor cells predict survival and recurrence patterns in patients undergoing resection for pancreatic cancer

Objective

To evaluate the prognostic impact of folate receptor (FR)-positive circulating tumor cells (FR⁺ CTCs) for patients with pancreatic cancer (PC).

Background

Risk stratification before surgery for PC patients remains challenging as there are no reliable prognostic markers currently. FR⁺ CTCs, detected by ligand-targeted polymerase chain reaction (LT-PCR), have shown excellent diagnostic value for PC in our previous study and prognostic value in a variety of cancer types.

Methods

Peripheral blood samples from 44 consecutive patients diagnosed with PC were analyzed for FR⁺ CTCs. 25 patients underwent tumor resection and were assigned to the surgical group. 19 patients failed to undergo radical resection because of local advance or distant metastasis and were assigned to the non-surgical group. The impact of CTCs on relapse and survival were explored.

Results

For the prognostic stratification, the optimal cut-off value of CTCs analyzed by receiver operating characteristic (ROC) curve was 14.49 folate units (FU)/3 ml. High CTC levels (> 14.49 FU/3 ml) were detected in 52.0% (13/25) of the patients in the surgical group and 63.2% (12/19) in the non-surgical group. In the surgical group, median disease-free survival (DFS) for patients with high CTC levels versus low CTC levels (< 14.49 FU/3 ml) was 8.0 versus 26.0 months (P = 0.008). In multivariable analysis, CTCs were an independent risk factor for DFS (HR: 4.589, P = 0.012). Concerning the recurrence patterns, patients with high CTC levels showed a significantly frequent rate of distant and early recurrence (P = 0.017 and P = 0.011). CTC levels remained an independent predictor for both distant (OR: 8.375, P = 0.014) and early recurrence (OR: 8.412, P = 0.013) confirmed by multivariable logistic regression. However, CTCs did not predict survival in the non-surgical group (P = 0.220).

Conclusion

FR⁺ CTCs in resected PC patients could predict impaired survival and recurrence patterns after surgery. Preoperative CTC levels detected by LT-PCR may help guide treatment strategies and further studies in a larger cohort are warranted.

Prognostic Significance of Intraoperative Peritoneal Lavage Cytology in Patients with Pancreatic Ductal Adenocarcinoma: A Single-Center Experience and Systematic Review of the Literature

BACKGROUND

The prognostic significance of peritoneal lavage cytology (PLC) in patients with pancreatic ductal adenocarcinoma (PDAC) remains controversial. The purpose of this study was to evaluate the prognostic impact of PLC status in PDAC patients.

METHODS

Patients intending to undergo resection for PDAC between 2007 and 2020 were included. Survival was compared among patients who underwent resection with negative or positive PLC status and those who did not undergo resection. Univariable and multivariable analyses were conducted to evaluate the prognostic impact of positive PLC status. A systematic literature review was performed to evaluate the correlation between prognosis and the positive PLC rate.

RESULTS

A total of 480 patients formed the study cohort and were divided as follows: 438 in the negative PLC group, 18 in the positive PLC group, and 24 in the no resection group. Although the median survival time significantly differed between the negative and positive PLC groups (35.7 vs. 13.6 months, P < 0.001), it did not significantly differ between the positive PLC and no resection groups (13.6 vs. 12.2 months, P = 0.605). Multivariable analyses demonstrated that positive PLC status (hazard ratio = 3.54, 95% confidence interval = 1.97-6.38, P < 0.001) was the strongest poor prognostic factor. Based on statistical analyses for the systematic review, the prognostic impact of positive PLC status weakened significantly as the institutional positive PLC rate increased (P = 0.044).

CONCLUSIONS

Resection did not improve the prognosis of patients with positive PLC status in our cohort. The institutional positive PLC rate may be a good reference for surgical indication in these patients.

Impact of Local Anesthetics on Cancer Behavior and Outcome during the Perioperative Period: A Review

There is a growing interest regarding the impact of the perioperative period and the application of anesthetic drugs on the recurrence of cancer metastases. Among them, the use of amide-type local anesthetics seems promising since in vitro studies and animal models have shown their potential to inhibit the Intercellular Adhesion Molecule 1 (ICAM-1) expression and Src activity, which are clearly implicated in the process of inflammation and cancer metastases. This review emphasizes the potential of amide-type local anesthetics in this context.

Circulating Tumor Cells and the Non-Touch Isolation Technique in Surgery for Non-Small-Cell Lung Cancer

Circulating tumor cells (CTCs) are dislodged from the primary tumor into the bloodstream, travel within the bloodstream to distant organs, and finally extravasate and proliferate as epithelial metastatic deposits. The relationship between the existence of CTCs and tumor prognosis has been demonstrated by many researchers. In surgery for malignancies, the surgical manipulation of tumors and tissues around the tumor may lead to the release of CTCs into the bloodstream. The non-touch isolation technique (NTIT) has been advocated to prevent the release of CTCs during surgery. The concept of NTIT is the prevention of intraoperative increment of CTCs from the primary tumor by the early blockade of outflow vessels, and ‘pulmonary vein (PV)-first lobectomy’ during surgery for non-small-cell lung cancer (NSCLC) corresponds to this technique. The concept of PV-first lobectomy is well known among thoracic surgeons, but evidence of its efficacy for preventing the increase of intra- and postoperative CTCs and for improving postoperative prognosis is still uncertain. Our study summarizes evidence regarding the relationship between NTIT and CTCs in NSCLC and suggests the need for further research on CTCs and CTC-detecting modalities.

Liquid Biopsy as a Prognostic and Theranostic Tool for the Management of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinomas (PDAC) represent one of the deadliest cancers worldwide. Survival is still low due to diagnosis at an advanced stage and resistance to treatment. Herein, we review the main types of liquid biopsy able to help in both prognosis and adaptation of treatments.

Circulating Tumor Cells Expressing Krüppel-Like Factor 8 and Vimentin as Predictors of Poor Prognosis in Pancreatic Cancer Patients

BACKGROUND

Circulating tumor cells (CTCs) with an epithelial-mesenchymal transition phenotype in peripheral blood may be a useful marker of carcinomas with poor prognosis. The aim of this study was to determine the prognostic significance of CTCs expressing Krüppel-like factor 8 (KLF8) and vimentin in pancreatic cancer (PC).

METHODS

CTCs were isolated by immunomagnetic separation from the peripheral blood of 40 PC patients before undergoing surgical resection. Immunocytochemistry was performed to identify KLF8⁺ and vimentin⁺ CTCs. The associations between CTCs and time to recurrence (TTR), clinicopathologic factors, and survival were assessed. Univariate and multivariate analyzes were performed to identify risk factors.

RESULTS

Patients with CTCs (n = 30) had a higher relapse rate compared to those without (n = 10) (70.0% vs 20.0%; P < 0.01). The proportion of KLF8⁺/vimentin⁺ CTCs to total CTCs was inversely related to TTR (r = -0.646; P < 0.01); TTR was reduced in patients with > 50% of CTCs identified as KLF8⁺/vimentin⁺ (P < 0.01). Independent risk factors for recurrence were perineural invasion and > 50% KLF8⁺/vimentin⁺ CTCs (both P < 0.05).

CONCLUSION

Poor prognosis can be predicted in PC patients when > 50% of CTCs are positive for KLF8 and vimentin.

CD44+ Circulating Tumor Endothelial Cells Indicate Poor Prognosis in Pancreatic Ductal Adenocarcinoma After Radical Surgery: A Pilot Study

Background

Circulating tumor endothelial cells (CTECs) are cells that originate from tumor endothelial cells (TECs) of blood vessels and are shed into peripheral blood. Some studies have shown that CTECs are associated with tumor angiogenesis, growth and indicate prognosis in patients with malignant solid tumor. However, the role of CTECs especially the phenotype of CTECs in pancreatic adenocarcinoma (PDAC) is still not clear. We investigated the relationship between CTECs and patients’ prognosis.

Methods

A total of 73 patients with resectable PDAC were enrolled in our research and underwent radical surgery. Peripheral venous blood samples were collected before surgery, on postoperative day (POD) 7 and on postoperative month (POM) 1, respectively. We used integrated subtraction enrichment and immunostaining-fluorescence in situ hybridization (SE-iFISH) platform to identify and enumerate CTECs. Immunofluorescence was used to identify CTECs expressing CD44 and vimentin.

Results

In patients with early tumor recurrence (DFS< 6 months), the preoperative CD44+ CTEC levels showed significantly higher (P = 0.023). Univariate and multivariate analysis showed that history of diabetes [HR 2.656 (1.194–5.908), P = 0.017], numbers of positive lymph nodes [HR 1.871 (1.388–2.522), P < 0.001], preoperative numbers of CD44+ CTECs [HR 1.216 (1.064–1.390), P = 0.004], and POM1 CA19-9 level [HR 1.002 (1.001–1.002), P < 0.001] were independent prognostic factors for DFS.

Conclusion

The detection of CD44+CTECs in patients with resectable PDAC preoperatively could be an independent predictor of shorter DFS after radical surgery.

Coupled liquid biopsy and bioinformatics for pancreatic cancer early detection and precision prognostication

Early detection and diagnosis are the key to successful clinical management of pancreatic cancer and improve the patient outcome. However, due to the absence of early symptoms and the aggressiveness of pancreatic cancer, its 5-year survival rate remains below 5 %. Compared to tissue samples, liquid biopsies are of particular interest in clinical settings with respect to minimal invasiveness, repeated sampling, complete representation of the entire or multi-site tumor bulks. The potential of liquid biopsies in pancreatic cancer has been demonstrated by many studies which prove that liquid biopsies are able to detect early emergency of pancreatic cancer cells, residual disease, and recurrence. More interestingly, they show potential to delineate the heterogeneity, spatial and temporal, of pancreatic cancer. However, the performance of liquid biopsies for the diagnosis varies largely across different studies depending of the technique employed and also the type and stage of the tumor. One approach to improve the detect performance of liquid biopsies is to intensively inspect circulome and to define integrated biomarkers which simultaneously profile circulating tumor cells and DNA, extracellular vesicles, and circulating DNA, or cell free DNA and proteins. Moreover, the diagnostic validity and accuracy of liquid biopsies still need to be comprehensively demonstrated and validated.

Local Anesthetics and Recurrence after Cancer Surgery-What's New? A Narrative Review

The perioperative use of regional anesthesia and local anesthetics is part of almost every anesthesiologist’s daily clinical practice. Retrospective analyses and results from experimental studies pointed towards a potential beneficial effect of the local anesthetics regarding outcome—i.e., overall and/or recurrence-free survival—in patients undergoing cancer surgery. The perioperative period, where the anesthesiologist is responsible for the patients, might be crucial for the further course of the disease, as circulating tumor cells (shed from the primary tumor into the patient’s bloodstream) might form new micro-metastases independent of complete tumor removal. Due to their strong anti-inflammatory properties, local anesthetics might have a certain impact on these circulating tumor cells, either via direct or indirect measures, for example via blunting the inflammatory stress response as induced by the surgical stimulus. This narrative review highlights the foundation of these principles, features recent experimental and clinical data and provides an outlook regarding current and potential future research activities.

Peritoneal Lavage Tumor DNA as a Novel Biomarker for Predicting Peritoneal Recurrence in Pancreatic Ductal Adenocarcinoma

BACKGROUND

The clinical role of peritoneal lavage cytology (CY) in pancreatic ductal adenocarcinoma (PDAC) remains controversial, partly due to its low sensitivity. This study aimed to develop a new biomarker, defined as peritoneal lavage tumor DNA (ptDNA), using DNAs extracted from peritoneal lavage samples from patients with PDAC.

METHODS

Samples were collected intraoperatively from 89 PDAC patients who underwent pancreatectomy between 2012 and 2017. Droplet digital polymerase chain reaction (PCR) was used to measure ptDNA for detection of KRAS mutations. The ptDNA status and clinical characteristics were retrospectively evaluated.

RESULTS

Positive ptDNA was found in 41 patients, including all 9 patients positive for CY (CY+) and 32 patients negative for CY (CY-). The mutant allele frequency was significantly higher in the CY+ patients than in the CY- patients. The disease-free survival (DFS) and overall survival (OS) were significantly poorer in the high-ptDNA group than in the low-ptDNA group (median DFS, 11.0 vs. 18.8 months; p = 0.007; median OS, 28.7 vs not reached; p = 0.001). The survival curves of DFS and OS in the CY+ group were almost equal to those in the CY- and high-ptDNA group. In a multivariable analysis, ptDNA was an independent predictive factor for DFS (p = 0.025) and OS (p = 0.047). The estimated cumulative incidence of peritoneal recurrence was 45.5% in the high-ptDNA group. The ptDNA biomarker had a much higher sensitivity for peritoneal recurrence than CY, whereas CY had higher specificity.

CONCLUSIONS

As a promising biomarker, ptDNA may predict poor prognosis and peritoneal recurrence in PDAC, resolving the controversy surrounding CY.

Circulating Tumor Cells are an Independent Predictor of Shorter Survival in Patients Undergoing Resection for Pancreatic and Periampullary Adenocarcinoma

OBJECTIVE

We evaluated the prognostic impact of circulating tumor cells (CTCs) for patients with presumed resectable pancreatic and periampullary cancers.

SUMMARY OF BACKGROUND DATA

Initial treatment decisions for this group are currently taken without a reliable prognostic marker. The CellSearch system allows standardized CTC-testing and has shown excellent specificity and prognostic value in other applications.

METHODS

Preoperative blood samples from 242 patients between September 2009 and December 2014 were analyzed. One hundred seventy-nine patients underwent tumor resection, of whom 30 with stage-I tumors and duodenal cancer were assigned to the low-risk group, and the others to the high-risk group. Further 33 had advanced disease, 30 benign histology. Observation ended in December 2016. Cancer-specific survival (CSS) and disease-free survival (DFS) were calculated by log-rank and Cox regression.

RESULTS

CTCs (CTC-positive; ≥1 CTC/7.5 mL) were detected in 6.8% (10/147) of the high-risk patients and 6.2% (2/33) with advanced disease. No CTCs (CTC-negative) were detected in the low-risk patients or benign disease. In high-risk patients, median CSS for CTC-positive versus CTC-negative was 8.1 versus 20.0 months (P < 0.0001), and DFS 4.0 versus 10.5 months (P < 0.001). Median CSS in advanced disease was 7.7 months. Univariate hazard ratio (HR) of CTC-positivity was 3.4 (P < 0.001). In multivariable analysis, CTC-status remained independent (HR: 2.4, P = 0.009) when corrected for histological type (HR: 2.7, P = 0.030), nodal status (HR: 1.7, P = 0.016), and vascular infiltration (HR: 1.7, P = 0.001).

CONCLUSION

Patients testing CTC-positive preoperatively showed a detrimental outcome despite successful tumor resections. Although the low CTC-rate seems a limiting factor, results indicate high specificity. Thus, preoperative analysis of CTCs by this test may guide treatment decisions and warrants further testing in clinical trials.

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.

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.

Liquid Biopsy Approach for Pancreatic Ductal Adenocarcinoma

Pancreatic cancer is a public health problem because of its increasing incidence, the absence of early diagnostic tools, and its aggressiveness. Despite recent progress in chemotherapy, the 5-year survival rate remains below 5%. Liquid biopsies are of particular interest from a clinical point of view because they are non-invasive biomarkers released by primary tumours and metastases, remotely reflecting disease burden. Pilot studies have been conducted in pancreatic cancer patients evaluating the detection of circulating tumour cells, cell-free circulating tumour DNA, exosomes, and tumour-educated platelets. There is heterogeneity between the methods used to isolate circulating tumour elements as well as the targets used for their identification. Performances for the diagnosis of pancreatic cancer vary depending of the technique but also the stage of the disease: 30–50% of resectable tumours are positive and 50–100% are positive in locally advanced and/or metastatic cases. A significant prognostic value is demonstrated in 50–70% of clinical studies, irrespective of the type of liquid biopsy. Large prospective studies of homogeneous cohorts of patients are lacking. One way to improve diagnostic and prognostic performances would be to use a combined technological approach for the detection of circulating tumour cells, exosomes, and DNA.

Clinical impact of different exosomes' protein expression in pancreatic ductal carcinoma patients treated with standard first line palliative chemotherapy

INTRODUCTION

Pancreatic ductal adenocarcinoma is associated to dismal prognosis despite the use of palliative chemotherapy, partly due to the lack of knowledge of biological processes underlying disease progression. Exosomes have been identified as biomarkers sources in different cancer types. Aim of the study was to analyse the contents of circulating exosomes in patients with pancreatic cancer who received palliative chemotherapy.

PATIENTS AND METHODS

Patients were submitted to blood sample collection before chemotherapy (T0) and after 3 months (T3). We quantified by an ELISA-based technique specific proteins of cancer-derived exosomes (CD44,CD44v6,EpCAM,CD9,CD81,Tspan8,Integrin α6,Integrin β4,CD24,CXCR4). We correlated the baseline levels of these factors and changes between T3 and T0 and survival outcomes. Survival analyses were performed by Kaplan-Meier method. Correlation was assessed by log-rank test and level of statistical significance was set at 0.05. Multivariate analysis was performed by logistic regression analysis.

RESULTS

Nineteen patients were enrolled. EpCAM T0 levels and increased EpCAM levels from T0 to T3 were those mostly associated with differences in survival. Patients having higher EpCAM had median progression free survival (PFS) of 3.18vs7.31 months (HR:2.82,95%CI:1.03-7.73,p = 0.01). Overall survival (OS) was shorter for patients having higher EpCAM (5.83vs16.45 months,HR:6.16,95%CI:1.93-19.58,p = 0.0001) and also response rates (RR) were worse (20%vs87%,p = 0.015). EpCAM increase during treatment was associated with better median PFS (2.88vs7.31 months,HR:0.24,95%CI:0.04-1.22,p = 0.003). OS was also better (8.75vs11.04 months, HR:0.77,95%CI:0.21-2.73,p = 0.66) and RR were 60%vs20% (p = 0.28). Among clinical factors that might determine changes on PFS and OS, only ECOG PS was associated to significantly worse PFS and OS (p = 0.0137and<0.001 respectively).Multivariate analysis confirmed EpCAM T0 levels and EpCAM T0/T3 changes as independent prognostic factors for PFS.

CONCLUSIONS

Pancreatic cancer patients exosomes express EpCAM, whose levels change during treatment. This represents a useful prognostic factor and also suggests that future treatment modalities who target EpCAM should be tested in pancreatic cancer patients selected by exosome EpCAM expression.

Subclinical cancer cell dissemination in peritoneal lavage fluid detected by reverse-transcription polymerase chain reaction identifies patients at high risk for peritoneal recurrence and consequent impaired survival in the setting of preoperative chemoradiation therapy for pancreatic cancer

BACKGROUND

Preoperative chemoradiation therapy is a promising strategy for pancreatic cancer. Peritoneal recurrence is a major recurrence pattern after surgery for pancreatic cancer following preoperative chemoradiation therapy, even in patients with negative peritoneal lavage fluid cytology. Previous reports have indicated that the detection of carcinoembryonic antigen mRNA by reverse transcription polymerase chain reaction is useful for evaluating subclinical tumor cell dissemination in peritoneal lavage fluid.

METHODS

Patients with resectable and borderline resectable pancreatic cancer treated with preoperative gemcitabine-based chemoradiation therapy and subsequent surgery were enrolled in this study. In all patients, a conventional cytologic examination of peritoneal lavage fluid from laparotomy confirmed the negative peritoneal cytology status. Carcinoembryonic antigen mRNA was detected in the peritoneal lavage fluid at laparotomy using reverse transcription polymerase chain reaction. Recurrence patterns and survival were evaluated in association with the carcinoembryonic antigen mRNA status in the peritoneal lavage fluid.

RESULTS

The peritoneal lavage fluid from 57 of the 237 patients (24%) was carcinoembryonic antigen mRNA(+). The carcinoembryonic antigen mRNA(+) patients had a significantly higher incidence of peritoneal recurrence than the carcinoembryonic antigen mRNA(-) patients (36% vs. 15%, P < .001). The 5-year survival rates of the carcinoembryonic antigen mRNA(+) and carcinoembryonic antigen mRNA(-) patients were 31% and 51%, respectively (P = .037). A multivariable analysis for survival revealed that borderline resectability, positive nodal status, and positive carcinoembryonic antigen mRNA status were independent variables for impaired survival.

CONCLUSION

Carcinoembryonic antigen mRNA(+) status was associated with a significantly increased incidence of peritoneal recurrence in patients with pancreatic cancer treated with preoperative chemoradiation therapy, resulting in impaired survival.

Pancreatic cancer circulating tumor cells: applications for personalized oncology

INTRODUCTION

Pancreatic cancer (PC) is a highly lethal disease, in part because of early metastasis, late diagnosis, and limited treatment options. Circulating tumor cells (CTCs) are cancer cells that have achieved the metastatic step of intravasation, and are thus a unique source of biomarkers with potential applications in the staging, prognostication, and treatment of PC. Areas covered: This review describes the use of CTCs in PC, including isolation methods, the significance of CTC enumeration, and studies examining phenotypic and molecular characteristics of CTCs. We also speculate on future directions for PC CTC research such as single-cell analysis and CTC culture. Expert commentary: CTCs represent a potential unique serial source of cancer tissue via a convenient and minimally invasive blood draw. Recent development of isolation methods that allow for the release of viable CTCs with unaltered molecular characteristics has set the stage for single-cell analysis and ex vivo culture. Although there is significant potential for CTCs as a biomarker to impact PC from diagnosis to therapy, there still remain a number of challenges to the routine implementation of CTCs in the clinical management of PC.

Effect of surgical liver resection on circulating tumor cells in patients with hepatocellular carcinoma

BACKGROUND

This study explored the effect of liver resection on perioperative circulating tumor cells (CTCs) and found that the prognostic significance of surgery was associated with changes in CTC counts in patients with hepatocellular carcinoma (HCC).

METHODS

One hundred thirty-nine patients with HCC were consecutively enrolled. The time-points for collecting blood were one day before operation and three days after operation. CTCs in the peripheral blood were detected by the CellSearch™ System.

RESULTS

Both CTC detection incidence and mean CTC counts showed greater increases postoperatively (54%, mean 1.54 cells) than preoperatively (43%, mean 1.13 cells). The postoperative CTC counts increased in 41.7% of patients, decreased in 25.2% of patients and did not change in 33.1% of patients. The increase in postoperative CTC counts was significantly associated with the macroscopic tumor thrombus status. Patients with increased postoperative CTC counts (from preoperative CTC < 2 to postoperative CTC ≥ 2) had significantly shorter disease-free survival (DFS) and overall survival (OS) than did patients with persistent CTC < 2. Patients with persistent CTC levels of ≥2 had the worst prognoses.

CONCLUSIONS

Surgical liver resection is associated with an increase in CTC counts, and increased postoperative CTC numbers are associated with a worse prognosis in patients with HCC.

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

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

Tumor manipulation during pancreatic resection for pancreatic cancer induces dissemination of tumor cells into the peritoneal cavity: a systematic review

BACKGROUND

Intraoperative tumor manipulation may induce the dissemination of occult peritoneal tumor cells (OPTC) into the peritoneal cavity.

METHODS

A systematic review was performed in the PubMed, Embase and Cochrane databases from inception to March 15, 2017. Eligible were studies that analyzed the presence of OPTC in peritoneal fluid, by any method, both before and after resection in adults who underwent intentionally curative pancreatic resection for histopathologically confirmed pancreatic ductal adenocarcinoma in absence of macroscopic peritoneal metastases.

RESULTS

Four studies with 138 patients met the inclusion criteria. The pooled rate of OPTC prior to tumor manipulation was 8% (95% CI 2%-24%). The pooled detection rate of OPTC in patients in whom OPTC became detectable only after tumor manipulation was 33% (95% CI 15-58%). Only one study (28 patients) reported on survival, which was worse in patients with OPTC (median 11.1 months versus 30.3 months; p = 0.030).

CONCLUSION

This systematic review suggests that tumor manipulation induces OPTC in one third of patients with pancreatic cancer. Since data on survival are lacking, future studies should determine the prognostic consequences of tumor manipulation, including the potential therapeutic effect of 'no-touch' and minimally invasive resection strategies.

Prognostic significance of circulating tumor microemboli in patients with pancreatic ductal adenocarcinoma

The significance of circulating tumor microemboli (CTMs) in patients with pancreatic ductal adenocarcinoma (PDAC) is still unknown. Thus, the present study used a epithelial cellular adhesion molecule independent subtraction and immunostaining-fluorescence in situ hybridization (SET-iFISH) platform to enumerate circulating tumor cells (CTCs) and CTMs in a total of 86 peripheral blood samples from 19 patients with PDAC. The associations between CTCs and CTMs with clinicopathologic factors and prognoses were analyzed. Prior to treatment, CTCs were detected in all 19 patients, and CTMs were detected in 4 patients with different tumor-node-metastasis (TNM) stages. A total of 85 of the 86 peripheral blood samples had cytokeratin 18-negative CTCs. The number of CTCs and CTMs were significantly associated with tumor size and vascular invasion. Patients with CTMs had poorer overall survival and disease-free survival when compared with those without CTMs (7.3 vs. 25.40 months, P=0.001; and 1.80 vs. 18.97 months, P=0.037). The presence of CTMs in the peripheral blood prior to surgery was predictive of poor prognosis in PDAC patients. CTMs could be detected in patients of different TNM stage (II, III and IV). Surgery did not benefit patients with CTMs, thus, surgeons should take greater consideration when assessing the requirements for surgery in patients with CTMs.

RT-PCR of peritoneal washings predicts peritoneal pancreatic cancer recurrence

BACKGROUND

Peritoneal recurrence of pancreatic cancer is a frequent and lethal outcome after R0 resection. A method to predict peritoneal recurrence could be helpful in its prevention.

MATERIALS AND METHODS

Peritoneal washings were prospectively obtained from 29 patients in whom R0 resection was performed. Cytological examination (CY) and real-time reverse transcription polymerase chain reaction (RT-PCR) of the peritoneal washing for the detection of cancer-related genes, CEACAM5, KRT7, KRAS, and MUC1, were performed. Clinicopathological characteristics and real-time RT-PCR results of the peritoneal washing were compared between patients whose pancreatic cancer recurred peritoneally (n = 7) and those patients who it did not recur (n = 22).

RESULTS

Only one CY-positive (CY⁺) case was detected, and that patient recurred. MUC1 mRNA expression was significantly higher in the recurrence group (P = 0.015). Cumulative incidence-function analysis demonstrated that peritoneal recurrence rate was significantly higher in MUC1-positive (MUC1⁺) patients (P = 0.044). MUC1⁺ patients had significantly decreased disease-free survival (P = 0.009) and disease-specific survival (P = 0.031). MUC1 protein was detected in the primary tumor in 18 of 29 patients. However, no significant difference was observed in the expression of MUC1 protein in peritoneal washings from the primary tumor (P = 0.579).

CONCLUSIONS

High expression of MUC1 mRNA in peritoneal washings is a significant risk factor for peritoneal recurrence of pancreatic cancer after R0 resection along with poor disease-specific survival. RT-PCR of MUC1 mRNA in peritoneal washing may be useful for individualization of adjuvant chemotherapy.

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.

Circulating and disseminated tumor cells in pancreatic cancer and their role in patient prognosis: a systematic review and meta-analysis

Background

Disseminated tumor cells (DTCs) and circulating tumor cells (CTCs) have been postulated to seed metastases and contribute to poorer patient outcomes in many types of solid cancer. To date, no systematic reviews have examined the role of both DTCs and CTCs in pancreatic cancer. We aimed to determine the prognostic value of DTCs/CTCs in pancreatic cancer using a systematic review and meta-analysis.

Materials and Methods

A comprehensive literature search identified studies examining DTCs and CTCs in the bone marrow and blood of pancreatic cancer patients at diagnosis with follow-up to determine disease-free/progression-free survival (DFS/PFS) and overall survival (OS). Statistical analyses were performed to determine the hazard ratio (HR) of DTCs/CTCs on DFS/PFS and OS.

Results

The literature search identified 16 articles meeting the inclusion criteria. The meta-analysis demonstrated statistically significant HR differences in DFS/PFS (HR = 1.93, 95% CI 1.19–3.11, P = 0.007) and OS (HR = 1.84, 95% CI 1.37–2.45, P =< 0.0001), indicating patients with detectable DTCs/CTCs at diagnosis have worse prognoses. Subgroup analyses suggested CTCs in the peripheral blood (HR =2.03) were more indicative of poor OS prognosis than DTCs in the bone marrow (HR = 1.91), although the difference between these was not statistically significant. Positivity of the CellSearch detection method for DTC/CTC had the highest correlation with decreased OS (HR = 2.79) while immunodetection (HR = 1.91) and RT-PCR (HR = 1.25) were less effective in determining prognosis.

Conclusion

The detection of DTCs/CTCs at diagnosis is associated with poorer DFS/PFS and OS in pancreatic cancer.

Circulating tumor cells and circulating tumor DNA: What surgical oncologists need to know?

As a result of recent progress in detection techniques, circulating tumor DNA (ctDNA) and circulating tumor cells (CTC) can now be accurately detected in the blood of most cancer patients. While these new biomarkers can provide a better understanding of key biological mechanisms underlying cancer growth and dissemination, they also open up a wide range of possible clinical applications in medical oncology, radiation oncology and surgical oncology. In this review, we summarize the results obtained with ctDNA and CTC together with their potential future clinical applications in the field of surgical oncology, with particular focus on the perioperative setting of various types of cancer. These applications include, but are not limited to, cancer screening, early diagnosis, prognostic assessment, evaluation and management of preoperative systemic or local therapies, post-surgical detection of minimal residual disease and early detection of cancer relapse.

Prognostic role of circulating tumor cells in patients with pancreatic cancer: a meta-analysis

BACKGROUND

Isolation and characterization of circulating tumor cells (CTCs) in patients suffering from a variety of different cancers have become hot biomarker topics. In this study, we evaluated the prognostic value of CTCs in pancreatic cancer.

MATERIALS AND METHODS

Initial literature was identified using Medline and EMBASE. The primary data were hazard ratios (HRs) with 95% confidence intervals (CIs) of survival outcomes, including overall survival (OS) and progression free survival/recurrence free survival (PFS/RFS).

RESULTS

A total of 9 eligible studies were included in this meta-analysis, published between 2002 and 2013. The estimated pooled HR and 95%CI for OS for all studies was 1.64 (95%CI 1.39-1.94, p<0.00001) and the pooled HR and 95%CI for RFS/DFS was 2.36 (95%CI 1.41-3.96, p<0.00001). The HRs and 95%CIs for OS and RFS/ DFS in patients before treatment were 1.93 (95%CI 1.26-2.96, p=0.003) and 1.82 (95%CI 1.22-2.72, p=0.003), respectively. In patients receiving treatment, the HRs and 95%CI for OS and RFS/DFS were 1.37 (95%CI 1.00- 1.86, p=0.05) and 1.89 (95%CI 1.01-3.51, p=0.05), respectively. Moreover, the pooled HR and 95%CI for OS in the post-treatment group was 2.20 (95%CI 0.80-6.02, p=0.13) and the pooled HR for RFS/DFS was 8.36 (95%CI 3.22-21.67, p<0.0001).

CONCLUSIONS

The meta-analysis provided strong evidence supporting the proposition that CTCs detected in peripheral blood have a fine predictive role in pancreatic patients especially on the time point of post-treatment.

Opportunities and Challenges for Pancreatic Circulating Tumor Cells

Sensitive and reproducible platforms have been developed for detection, isolation, and enrichment of circulating tumor cells (CTCs)-rare cells that enter the blood from solid tumors, including those of the breast, prostate gland, lung, pancreas, and colon. These might be used as biomarkers in diagnosis or determination of prognosis. CTCs are no longer simply detected and quantified; they are now used in ex vivo studies of anticancer agents and early detection. We review what we have recently learned about CTCs from pancreatic tumors, describing advances in their isolation and analysis and challenges to their clinical utility. We summarize technologies used to isolate CTCs from blood samples of patients with pancreatic cancer, including immunoaffinity and label-free physical attribute-based capture. We explain methods of CTC analysis and how findings from these studies might be used to detect cancer at earlier stages, monitor disease progression, and determine prognosis. We review studies that have expanded CTCs for testing of anticancer agents and how these approaches might be used to personalize treatment. Advances in the detection, isolation, and analysis of CTCs have increased our understanding of the dissemination and progression of pancreatic cancer. However, standardization of methodologies and prospective studies are needed for this emerging technology to have a significant effect on clinical care.

Pancreatic cancer: Are "liquid biopsies" ready for prime-time?

Pancreatic cancer is a disease that carries a poor prognosis. Accurate tissue diagnosis is required. Tumours contain a high content of stromal tissue and therefore biopsies may be inconclusive. Circulating tumour cells (CTCs) have been investigated as a potential “liquid biopsy” in several malignancies and have proven to be of prognostic value in breast, prostate and colorectal cancers. They have been detected in patients with localised and metastatic pancreatic cancer with sensitivities ranging from 38%-100% using a variety of platforms. Circulating tumour DNA (ctDNA) has also been detected in pancreas cancer with a sensitivity ranging from 26%-100% in studies across different platforms and using different genetic markers. However, there is no clear consensus on which platform is the most effective for detection, nor which genetic markers are the most useful to use. Potential roles of liquid biopsies include diagnosis, screening, guiding therapies and prognosis. The presence of CTCs or ctDNA has been shown to be of prognostic value both at diagnosis and after treatment in patients with pancreatic cancer. However, more prospective studies are required before this promising technology is ready for adoption into routine clinical practice.

Role of detection of circulating tumor cells in early diagnosis of pancreatic cancer

Pancreatic cancer is a kind of highly malignant digestive system tumor. The early clinical symptoms of pancreatic cancer are insidious and atypical, so it is difficult to early diagnose pancreatic cancer, and most patients are diagnosed at an advanced stage. Therefore, the early diagnosis of pancreatic cancer is of great clinical significance for improving prognosis. Circulating tumor cells are a group of tumor cells that are present in patient's peripheral blood, which mainly reflects tumor metastasis. However, studies have found that circulating tumor cells may have entered the blood before primary cancer is diagnosed. If circulating tumor cells could be early detected in patient's peripheral blood, this would increase the rate of early diagnosis of the tumor. This paper mainly introduces the detection of circulating tumor cells and its role in the early diagnosis of pancreatic cancer.

Perioperative circulating tumor cell detection: Current perspectives

Primary cancer resections and in selected cases surgical metastasectomies significantly improve survival, however many patients develop recurrences. Circulating tumor cells (CTCs) function as an independent marker that could be used in the prognostication of different cancers. Sampling of blood and bone marrow compartments during cancer resections is a unique opportunity to increase individual tumor cell capture efficiency. This review will address the diagnostic and therapeutic potentials of perioperative tumor isolation and highlight the focus of future studies on characterization of single disseminated cancer cells to identify targets for molecular therapy and immune escape mechanisms.

Circulating tumor cell isolation during resection of colorectal cancer lung and liver metastases: a prospective trial with different detection techniques

BACKGROUND

Colorectal cancer (CRC) metastasectomy improves survival, however most patient develop recurrences. Circulating tumor cells (CTCs) are an independent prognostic marker in stage IV CRC. We hypothesized that CTCs can be enriched during metastasectomy applying different isolation techniques.

METHODS

25 CRC patients undergoing liver (16 (64%)) or lung (9 (36%)) metastasectomy were prospectively enrolled (clinicaltrial.gov identifier: NCT01722903). Central venous (liver) or radial artery (lung) tumor outflow blood (7.5 ml) was collected at incision, during resection, 30 min after resection, and on postoperative day (POD) 1. CTCs were quantified with 1. EpCAM-based CellSearch® system and 2. size-based isolation with a novel filter device (FMSA). CTCs were immunohistochemically identified using CellSearch®'s criteria (cytokeratin 8/18/19+, CD45- cells containing a nucleus (DAPI+)). CTCs were also enriched with a centrifugation technique (OncoQuick®).

RESULTS

CTC numbers peaked during the resection with the FMSA in contrast to CellSearch® (mean CTC number during resection: FMSA: 22.56 (SEM 7.48) (p = 0.0281), CellSearch®: 0.87 (SEM ± 0.44) (p = 0.3018)). Comparing the 2 techniques, CTC quantity was significantly higher with the FMSA device (range 0-101) than CellSearch® (range 0-9) at each of the 4 time points examined (P < 0.05). Immunofluorescence staining of cultured CTCs revealed that CTCs have a combined epithelial (CK8/18/19) and macrophage (CD45/CD14) phenotype.

CONCLUSIONS

Blood sampling during CRC metastasis resection is an opportunity to increase CTC capture efficiency. CTC isolation with the FMSA yields more CTCs than the CellSearch® system. Future studies should focus on characterization of single CTCs to identify targets for molecular therapy and immune escape mechanisms of cancer cells.

Clinical Significance of Circulating Tumor Microemboli as a Prognostic Marker in Patients with Pancreatic Ductal Adenocarcinoma

BACKGROUND

Characterization of circulating tumor cells (CTCs) has been used to provide prognostic, predictive, and pharmacodynamic information in many different cancers. However, the clinical significance of CTCs and circulating tumor microemboli (CTM) in patients with pancreatic ductal adenocarcinoma (PDAC) has yet to be determined.

METHODS

In this prospective study, CTCs and CTM were enumerated in the peripheral blood of 63 patients with PDAC before treatment using anti-EpCAM (epithelial cell adhesion molecule)–conjugated supported lipid bilayer–coated microfluidic chips. Associations of CTCs and CTM with patients' clinical factors and prognosis were determined.

RESULTS

CTCs were abundant [mean (SD), 70.2 (107.6)] and present in 81% (51 of 63) of patients with PDAC. CTM were present in 81% (51 of 63) of patients with mean (SD) 29.7 (1101.4). CTM was an independent prognostic factor of overall survival (OS) and progression free survival (PFS). Patients were stratified into unfavorable and favorable CTM groups on the basis of CTM more or less than 30 per 2 mL blood, respectively. Patients with baseline unfavorable CTM, compared with patients with favorable CTM, had shorter PFS (2.7 vs 12.1 months; P &lt; 0.0001) and OS (6.4 vs 19.8 months; P &lt; 0.0001). Differences persisted if we stratified patients into early and advanced diseases. The number of CTM before treatment was an independent predictor of PFS and OS after adjustment for clinically significant factors.

CONCLUSIONS

The number of CTM, instead of CTCs, before treatment is an independent predictor of PFS and OS in patients with PDAC.

No-touch isolation techniques for pancreatic cancer

The rate of recurrence, including liver metastasis is high in pancreatic cancer, even when complete surgical resection is performed as a curative treatment. In patients with pancreatic cancer, the handling and grasping of the pancreas during surgery may increase the risk of liver metastasis, as squeezing may spread cancer cells via the portal vein. A no-touch isolation technique might prevent the spread of cancer cells via the hematogenous metastatic route in patients with pancreatic cancer. However, while no-touch isolation techniques are simple, feasible and, in theory, ideal procedures for the surgical treatment of pancreatic cancer, there have been no randomized controlled prospective studies to validate their advantages and their efficacy remains controversial. It is, therefore, worth investigating the use of no-touch isolation techniques in pancreatic cancer.

Gene expression profiling and DNA methylation analyses of CTCs

A variety of molecular assays have been developed for CTCs detection and molecular characterization. Molecular assays are based on the nucleic acid analysis in CTCs and are based on total RNA isolation and subsequent mRNA quantification of specific genes, or isolation of genomic DNA that can be for DNA methylation studies and mutation analysis. This review is mainly focused on gene expression and methylation studies in CTCs in various types of cancer.

Clinical applications of circulating tumor DNA and circulating tumor cells in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is the most frequent pancreatic cancer type and is characterized by a dismal prognosis due to late diagnosis, local tumor invasion, frequent distant metastases and poor sensitivity to current therapy. In this context, circulating tumor cells and circulating tumor DNA constitute easily accessible blood-borne tumor biomarkers that may prove their clinical interest for screening, early diagnosis and metastatic risk assessment of PDAC. Moreover these markers represent a tool to assess PDAC mutational landscape. In this review, together with key biological findings, we summarize the clinical results obtained using "liquid biopsies" at the different stages of the disease, for early and metastatic diagnosis as well as monitoring during therapy.

Keratin 19 protein expression is an independent predictor of survival in human hepatocellular carcinoma

AIM

We aimed to assess the clinicopathological relevance and prognostic significance of expression of the hepatic progenitor cell markers keratin 19 (K19), epithelial cell adhesion molecule (EpCAM) and CD117 (c-KIT) in a White series of hepatocellular carcinoma (HCC).

METHODS

We evaluated the immunohistochemical expression of K19, EpCAM and CD117 in 89 surgical specimens of HCC from Greek patients (mean age 66.7±11.3 years, male 75.2%) followed up for 39.6±25.3 months.

RESULTS

K19, EpCAM and CD117 expression was detected in tumour cells of 10.11, 15.38 and 3.7% HCCs, respectively. Female sex was correlated with EpCAM immunohistochemical expression (P=0.035), whereas no other significant relationship with clinicopathological parameters was observed. K19 positivity tended to be correlated with microvascular invasion (P=0.054). In univariate analysis, K19 positivity and microvascular invasion were found to be associated with decreased recurrence-free survival (P<0.001 and P=0.004, respectively) and overall survival (P=0.002 and P=0.029, respectively). EpCAM and CD117 positivity was not correlated with patient survival. In multivariate analysis, K19 positivity emerged as an independent predictor of recurrence-free survival (odds ratio=7.84, 95% confidence interval=2.658-22.912, P<0.001) and overall survival (odds ratio=3.845, 95% confidence interval=1.401-10.549, P=0.009).

CONCLUSION

Our study confirms the prognostic significance of K19 expression in Caucasian patients with HCCs, providing further evidence that it may be used to stratify HCC according to tumour aggressiveness.

Pancreatic ductal adenocarcinoma: From genetics to biology to radiobiology to oncoimmunology and all the way back to the clinic

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer death. Despite improvements in the clinical management, the prognosis of PDAC remains dismal. In the present comprehensive review, we will examine the knowledge of PDAC genetics and the new insights into human genome sequencing and clonal evolution. Additionally, the biology and the role of the stroma in tumour progression and response to treatment will be presented. Furthermore, we will describe the evidence on tumour chemoresistance and radioresistance and will provide an overview on the recent advances in PDAC metabolism and circulating tumour cells. Next, we will explore the characteristics and merits of the different mouse models of PDAC. The inflammatory milieu and the immunosuppressive microenvironment mediate tumour initiation and treatment failure. Hence, we will also review the inflammatory and immune escaping mechanisms and the new immunotherapies tested in PDAC. A better understanding of the different mechanisms of tumour formation and progression will help us to identify the best targets for testing in future clinical studies of PDAC.

Patterns of circulating tumor cells identified by CEP8, CK and CD45 in pancreatic cancer

To improve the identification for CTCs with weak or negative CK and diploid CTCs in pancreatic cancer, we combined immune-staining of CK, CD45, DAPI and fluorescence in situ hybridization with the centromere of chromosome 8 (CEP8) probe method. CTCs in 3.75 mL of blood were depleted for CD45 positive cells with anti-CD45 antibodies and identified by combining CK, CD45, DAPI and CEP8 in 61 cases including 22 pancreatic cancers, 3 borderline pancreatic solid pseudopapillary tumors, 6 pancreatic benign tumors, and 30 healthy individuals. We found that enriched cells could be classified into 5 patterns: CK+CD45-DAPI+CEP8=2 (2 hybridization signals), CK+CD45-DAPI+CEP8>2 (>2 hybridization signals), CK-CD45-DAPI+CEP8>2, CK-CD45-DAPI+CEP8=2, and CK+/-CD45+DAPI+CEP8=2 or >2. Among 22 pancreatic cancers, CK+CD45-DAPI+CEP8=2 and CK+CD45-DAPI+CEP8>2 patterns were identified in two cases, and CK-CD45- DAPI+CEP8>2 pattern was identified in 16 cases. CK-CD45-DAPI+CEP8=2 and CK+/-CD45+DAPI+CEP8=2 or >2 patterns were detected in pancreatic cancers, other pancreatic diseases and healthy individuals. Among the five patterns, CK+CD45-DAPI+CEP8=2, CK+CD45-DAPI+CEP8>2 and CK-CD45-DAPI+CEP8>2 were considered as CTCs, while CK-CD45-DAPI+CEP8=2 and CK+/-CD45+DAPI+CEP8=2 or >2 were considered as indeterminate cells. When the cutoff value was set as 2 cells/3.75 mL based on ROC curve, the sensitivity and specificity in the diagnosis of pancreatic cancer was 68.18 and 94.87%, respectively. Dynamically monitoring CTCs changes prior to and after surgery in pancreatic patients revealed that CTCs count decreased in 3 days after surgery, but increased in 10 days after surgery in most patients. During our one and a half year follow-up, CTCs positive patients showed metastasis and worse survival rate.

Circulating tumor cells in the central and peripheral venous compartment - assessing hematogenous dissemination after transarterial chemoembolization of hepatocellular carcinoma

The aims of this study were to assess the effect of transarterial chemoembolization (TACE) on circulating tumor cells (CTCs) in the peripheral blood and right atrium of patients with HCC and to evaluate whether perioperative shedding of CTCs affects time to progression of HCC. Before and after TACE, peripheral and right atrial blood samples (7.5 mL) were collected from 42 patients with HCC. CTCs were enriched using EpCAM antibody-conjugated magnetic beads. The number of CTCs was 0–30 and 0–54 in peripheral blood before and after TACE, respectively (P=0.166), and 0–65 and 0–98 in the right atrium before and after TACE, respectively (P=0.102). The number of CTCs was significantly different between the two samples both before (P=0.007) and after (P=0.021) TACE. There was no difference in time to progression between patients with and without an increase in the number of CTCs after TACE in either sample (P>0.05 for both). There were more CTCs in right atrial blood than in peripheral blood. The numbers of CTCs in both samples remained unchanged after TACE. Shedding of tumor cells did not affect time to progression of disease in patients with HCC.

Sensitivity of alternative testing for pancreaticobiliary cancer: a 10-y review of the literature

BACKGROUND

Biliary strictures present a diagnostic challenge to differentiate benign disease from hepatopancreaticobiliary (HPB) malignancies. Endoscopic retrograde cholangiopancreatography cytology is commonly performed in these patients; however, its sensitivity for diagnosis of HPB malignancy is poor (41.6%). Many adjunctive tests have been investigated to improve the sensitivity of HPB biopsies. To determine the best tests available, however, we reviewed the literature and performed a comparative analysis of all recently investigated tests and their sensitivities.

METHODS

A PubMed search identified articles published between 2003 and 2014, describing alternate methods for diagnosing HPB malignancies, reported sensitivity, final pathology, and had data available online. Meta-analysis was conducted for tests with multiple articles. Tests with the highest sensitivity and specificities were reported.

RESULTS

A total of 77 studies were identified. Meta-analysis was performed on the sensitivity of EUS-FNA (74.2%), fluorescence in situ hybridization (54.2%), immunostain of insulin-like growth factor 2 mRNA-binding Protein 3 (IMP3; 80.4%), IMP3 + cytology (86.4%), K homology domain containing protein overexpressed in cancer (KOC; 85.9%), S100P (77.8%), serum CA19-9 (69.3%), and K-ras mutations (47.0%) to detect malignancy. Ultimately, 12 tests were identified with superior sensitivity (85.3%-100%) and specificities (81.6%-100%) including stricture scrapping, brush sectioning, IMP3 stain + cytology, IMP3+S100A4, bile carcinoembryonic cell adhesion molecule 6 protein (±CA19-9), bile micro RNA (miRNA)-135b, serum miRNA-RNU2-1f, serum miRNA-21 (+CA19-9), peripheral blood mononuclear cells miRNA-27a-3p (+CA19-9), serum miRNA-16 + miRNA-196a (+CA19-9), peripheral blood mononuclear cells mRNAs h-TERT + CK20 + CEA + C-MET.

CONCLUSIONS

We recommend immunostaining with a panel of IMP3+KOC + S100A4 + cytology to achieve maximum sensitivity and specificity from HPB biopsies. One biliary protein (carcinoembryonic cell adhesion molecule 6) and several RNAs (bile and blood) offer exceptional sensitivity and specificity and should be tested prospectively in larger populations. Overall, this review identifies several tests to improve the sensitivity of diagnostic algorithms to identify HPB malignancies.

Prognostic value of circulating tumor cells in patients with pancreatic cancer: a meta-analysis

Increasing scientific evidences suggest that circulating tumor cells (CTC) in peripheral blood may be a powerful predictor of survival in patients with pancreatic cancer. However, many existing studies have yielded inconclusive results. This meta-analysis aims to assess the prognostic value of CTC in patients with pancreatic cancer. An extensive literary search for relevant studies was conducted on PubMed, Embase, Web of Science, Cochrane Library, CISCOM, CINAHL, Google Scholar, CNKI, and CBM databases from their inception through July 1, 2013. The meta-analysis was then performed using the Stata 12.0 software. Crude hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated under a fixed or random effect model. Nine cohort studies were included in this meta-analysis with a total of 623 pancreatic cancer patients. This number included 268 CTC-positive patients and 355 CTC-negative patients. Our meta-analysis revealed that patients in the CTC-positive group were significantly associated with poor progression-free survival (PFS) (HR = 1.89, 95% CI = 1.25-4.00, P < 0.001). Furthermore, pancreatic cancer patients in the CTC-positive group also showed worse overall survival (OS) than those in the CTC-negative group (HR = 1.23, 95% CI = 0.88-2.08, P < 0.001). Subgroup analysis by ethnicity indicated that CTC-positive patients had poor OS among both Asian and Caucasian populations (all P < 0.05). Further subgroup analyses by detection and treatment methods also suggested that CTC-positive patients showed worser OS than CTC-negative patients in the majority of subgroups (all P < 0.05). No publication bias was detected in this meta-analysis. In conclusion, our meta-analysis suggests that CTC-positive pancreatic cancer patients may have worser PFS and OS than CTC-negative patients. Detection of CTC in peripheral blood may be a promising biomarker for the detection and prognosis of pancreatic cancer.