Carcinoembryonic antigen messenger RNA expression using nested reverse transcription-PCR in the peripheral blood during follow-up period of patients who underwent curative surgery for biliary-pancreatic cancer: longitudinal analyses

Surveillance after surgery for pancreatic cancer: a global scoping review of guidelines and a nordic Survey of contemporary practice

OBJECTIVES

Most patients with pancreatic cancer who have undergone surgical resection eventually develop disease recurrence. ‍This study aimed to investigate whether there is evidence to support routine surveillance after pancreatic cancer surgery, with a secondary aim of analyzing the implementation of surveillance strategies in the Nordic countries.

MATERIALS AND METHODS

A scoping review was conducted to identify clinical practice guidelines globally and research studies relating to surveillance after pancreatic cancer resection. This was followed by a survey among 20 pancreatic units from four Nordic countries to assess their current practice of follow-up for operated patients.

RESULTS

Altogether 16 clinical practice guidelines and 17 research studies were included. The guidelines provided inconsistent recommendations regarding postoperative surveillance of pancreatic cancer. The clinical research data were mainly based on retrospective cohort studies with low level of evidence and lead-time bias was not addressed. Active surveillance was recommended in Sweden and Denmark, but not in Norway beyond the post-operative/adjuvant period. Finland had no national recommendations for surveillance. The Nordic survey revealed a wide variation in reported practice among the different units. About 75% (15 of 20 units) performed routine postoperative surveillance. Routine CA 19-9 testing was used by 80% and routine CT by 67% as part of surveillance. About 73% of centers continued follow-up until 5 years postoperatively.

CONCLUSION

Evidence for routine long-term (i.e. 5 years) surveillance after pancreatic cancer surgery remains limited. Most pancreatic units in the Nordic countries conduct regular follow-up, but protocols vary.

Dynamics of Serum CA19-9 in Patients Undergoing Pancreatic Cancer Resection

BACKGROUND

Carbohydrate antigen (CA) 19-9 is an established perioperative prognostic biomarker for pancreatic ductal adenocarcinoma (PDAC). However, it is unclear how CA19-9 monitoring should be used during postoperative surveillance to detect recurrence and to guide the initiation of recurrence-focused therapy.

OBJECTIVE

This study aimed to elucidate the value of CA19-9 as a diagnostic biomarker for disease recurrence in patients who underwent PDAC resection.

METHODS

Serum CA19-9 levels at diagnosis, after surgery, and during postoperative follow-up were analyzed in patients who underwent PDAC resection. All patients with at least two postoperative follow-up CA19-9 measurements before recurrence were included. Patients deemed to be nonsecretors of CA19-9 were excluded. The relative increase in postoperative CA19-9 was calculated for each patient by dividing the maximum postoperative CA19-9 value by the first postoperative value. Receiver operating characteristic analysis was performed to identify the optimal threshold for the relative increase in CA19-9 levels to identify recurrence in the training set using Youden's index. The performance of this cutoff was validated in a test set by calculating the area under the curve (AUC) and was compared to the performance of the optimal cutoff for postoperative CA19-9 measurements as a continuous value. In addition, sensitivity, specificity, and predictive values were assessed.

RESULTS

In total, 271 patients were included, of whom 208 (77%) developed recurrence. Receiver operating characteristic analysis demonstrated that a relative increase in postoperative serum CA19-9 of 2.6× was predictive of recurrence, with 58% sensitivity, 83% specificity, 95% positive predictive value, and 28% negative predictive value. The AUC for a 2.6× relative increase in the CA19-9 level was 0.719 in the training set and 0.663 in the test set. The AUC of postoperative CA19-9 as a continuous value (optimal threshold, 52) was 0.671 in the training set. In the training set, the detection of a 2.6-fold increase in CA19-9 preceded the detection of recurrence by a mean difference of 7 months ( P <0.001) and in the test set by 10 months ( P <0.001).

CONCLUSIONS

A relative increase in the postoperative serum CA19-9 level of 2.6-fold is a stronger predictive marker for recurrence than a continuous CA19-9 cutoff. A relative CA19-9 increase can precede the detection of recurrence on imaging for up to 7 to 10 months. Therefore, CA19-9 dynamics can be used as a biomarker to guide the initiation of recurrence-focused treatment.

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.

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.

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.

Circulating tumour cells as an indicator of early and systemic recurrence after surgical resection in pancreatic ductal adenocarcinoma

Early recurrence in pancreatic ductal adenocarcinoma (PDAC) is a decisive factor in determining a patient's prognosis. We determined in our current study whether circulating tumour cells (CTCs) exist in the blood of PDAC patients and can be used as a predictor of recurrence patterns (i.e. time and site) after surgical resection. Between December 2017 and November 2018, the mononuclear cell layer was obtained from the peripheral blood of 36 patients diagnosed with PDAC. CTCs were then isolated using the CD-PRIME™ platform and detected via immunostaining. The patient records were analyzed to correlate these data with survival and recurrence patterns. Twelve patients were CTC-positive (33.3%) and showed a significantly frequent rate of systemic recurrence (distant metastases and peritoneal dissemination) (p = 0.025). On multi-variable logistic regression analysis, CTC positivity was an independent risk factor for early recurrence (p = 0.027) and for systemic recurrence (p = 0.033). In summary, the presence or absence of CTC in the blood of the patients with PDAC could help predict the recurrence pattern after surgery. PDAC patients with CTC positivity at tumour diagnosis should therefore undergo a comprehensive strategy for systemic therapy and active monitoring to detect possible early recurrence.

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.

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.

The emerging role of liquid biopsy in diagnosis, prognosis and treatment monitoring of pancreatic cancer

Circulating tumor DNA, circulating tumor cells and tumor-related exosomes may offer new opportunities to provide insights into the biological and clinical characteristics of a neoplastic disease. They represent alternative routes for diagnostic and prognostic purposes, and for predicting and longitudinally monitoring response to treatment and disease progression. Hence, circulating biomarkers represent promising noninvasive tools in the scenario of pancreatic cancer, where neither molecular nor clinical predictors of treatment benefit have been identified yet. This review aims to provide an overview of the current status of circulating biomarker research in pancreatic cancer, and discusses their potential clinical utility to facilitate clinical decision-making.

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.

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.

Systematic review on the role of serum tumor markers in the detection of recurrent pancreatic cancer

BACKGROUND

Biomarker testing can be helpful to monitor disease progression after resection of pancreatic cancer. This systematic review aims to give an overview of the literature on the diagnostic value of serum tumor markers for the detection of recurrent pancreatic cancer during follow-up.

METHODS

A systematic search was performed to 2 October 2017. All studies reporting on the diagnostic value of postoperatively measured serum biomarkers for the detection of pancreatic cancer recurrence were included. Data on diagnostic accuracy of tumor markers were extracted. Forest plots and pooled values of sensitivity and specificity were calculated.

RESULTS

Four articles described test results of CA 19-9. A pooled sensitivity and specificity of respectively 0.73 (95% CI 0.66-0.80) and 0.83 (95% CI 0.73-0.91) were calculated. One article reported on CEA, showing a sensitivity of 50% and specificity of 65%. No other serum tumor markers were discussed for surveillance purposes in the current literature.

CONCLUSION

Although testing of serum CA 19-9 has considerable limitations, CA 19-9 remains the most used serum tumor marker for surveillance after surgical resection of pancreatic cancer. Further studies are needed to assess the role of serum tumor marker testing in the detection of recurrent pancreatic cancer and to optimize surveillance strategies.

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.

Clinical impact of circulating tumor cells and therapy response in pancreatic cancer

BACKGROUND

Among gastrointestinal cancers, the prognosis of pancreatic cancer is one of the poorest, with a large number of patients being diagnosed with unresectable tumors at the first visit to a doctor. The aims of the present study were to investigate the circulating tumor cells (CTC) in peripheral blood in order to assess their clinical significance in patients with pancreatic cancer.

METHODS

Sixty-five patients with advanced pancreatic cancer were enrolled. Borderline resectable pancreatic tumor patients were 9, and Unresectable patients were 56. The CellSearch system was used to isolate and enumerate CTCs.

RESULTS

CTCs were identified in 21 out of 65 patients (32.3%) with only unresectable tumors. The overall survival rate was significantly lower in unresectable patients with than in those without CTCs (P = 0.0051). CTC positivity was significantly higher in patients with than in those without liver metastasis. A multivariate analysis identified the presence or absence of CTCs as an independent prognostic factor. Follow-up blood specimens were obtained from 40 patients treated with chemotherapy or chemoradiotherapy. The incidences of CTC positivity at three months after beginning of treatments in patients with progressive disease and stable disease or a partial response were 45.4% and 24.1%, respectively. The overall survival rate was significantly lower in patients with than in those without CTCs even after treatments (P = 0.045).

CONCLUSION

CTC numbers represents a useful tool for predicting prognoses and therapeutic responses to chemotherapy among patients with advanced 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.

Liquid biopsy in patients with pancreatic cancer: Circulating tumor cells and cell-free nucleic acids

Despite recent advances in surgical techniques and perioperative management, the prognosis of pancreatic cancer (PCa) remains extremely poor. To provide optimal treatment for each patient with Pca, superior biomarkers are urgently needed in all phases of management from early detection to staging, treatment monitoring, and prognosis. In the blood of patients with cancer, circulating tumor cells (CTCs) and cell-free nucleic acids (cfNAs), such as DNA, mRNA, and noncoding RNA have been recognized. In the recent years, their presence in the blood has encouraged researchers to investigate their potential use as novel blood biomarkers, and numerous studies have demonstrated their potential clinical utility as a biomarker for certain types of cancer. This concept, called “liquid biopsy” has been focused on as a less invasive, alternative approach to cancer tissue biopsy for obtaining genetic and epigenetic aberrations that contribute to oncogenesis and cancer progression. In this article, we review the available literature on CTCs and cfNAs in patients with cancer, particularly focusing on PCa, and discuss future perspectives in this field.

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.

Circulating Tumor Cells in Gastrointestinal Cancer: Current Practices and Future Directions

GI cancers are the leading cause of cancer-related death worldwide primarily due to a combination of late presentation and aggressive biology. The lack of adequate biomarkers for screening, diagnosis, staging, and prognosis confounds clinical decision-making and delays potentially effective therapies. Circulating tumor cells (CTCs) are a new biomarker with particular promise in GI cancers, potentially offering clinicians and researchers real-time access to tumor tissue in a reliable, safe, and cost-effective manner. Preliminary studies have investigated the potential clinical utility of CTCs for all GI cancer types with promising results. Furthermore, advances in single cell analytics have been successfully applied to CTCs, allowing for exciting new clinical and research applications. In this chapter, we will review the current state of CTC research in GI cancers as well as the potential future applications that are currently being developed.

Improving pancreatic cancer diagnosis using circulating tumor cells: prospects for staging and single-cell analysis

Pancreatic cancer (PC) is the fourth most common cause of cancer-related death in the USA, primarily due to late presentation coupled with an aggressive biology. The lack of adequate biomarkers for diagnosis and staging confound clinical decision-making and delay potentially effective therapies. Circulating tumor cells (CTCs) are a promising new biomarker in PC. Preliminary studies have demonstrated their potential clinical utility, and newer CTC isolation platforms have the potential to provide clinicians access to tumor tissue in a reliable, real-time manner. Such a 'liquid biopsy' has been demonstrated in several cancers, and small studies have demonstrated its potential applications in PC. This article reviews the available literature on CTCs as a biomarker in PC and presents the latest innovations in CTC research as well as their potential applications in PC.

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.

Biomarkers as predictors of recurrence following curative resection for pancreatic ductal adenocarcinoma: a review

Pancreatic ductal adenocarcinoma (PDA) is the fourth most common cancer causing death in the United States. Early tumor recurrence is an important contributor to the dismal prognosis. The availability of an accurate prognostic biomarker for predicting disease recurrence following curative resection will be beneficial for patient care. Most of the currently studied biomarkers remain in the investigational phase, with CA 19-9 being the only biomarker currently approved by the FDA. Herein, we review the utility of CA 19-9 and other investigational cellular, gene, and molecular tumor markers for predicting PDA recurrence following curative surgical resection.

B7-H3 expression in gastric cancer: a novel molecular blood marker for detecting circulating tumor cells

The clinical significance of B7-H3 expression in gastric cancer remains unclear, although the B7 ligand family plays a critical role in the T cell-mediated immune response. We therefore investigated B7-H3 expression as a blood marker of circulating tumor cells and determined correlations with tumor progression in patients with gastric cancer. B7-H3 expression in gastric cell lines was initially evaluated by immunocytochemistry. Furthermore, we used quantitative RT-PCR to assess B7-H3 mRNA expression in four cell lines and in 95 blood specimens from patients with gastric cancer, as well as in 21 samples of peripheral blood lymphocytes from healthy volunteers. B7-H3 expression in cell lines was identified by immunocytochemistry and quantitative RT-PCR. Blood specimens from patients with gastric cancer contained significantly more copies of B7-H3 mRNA than those from healthy volunteers without cancer (P < 0.0001). Levels of B7-H3 expression significantly correlated with overall stage (P = 0.013). The 5-year survival rate was significantly lower in patients with high B7-H3 expression than with low expression (P = 0.02). Multivariate analysis demonstrated that B7-H3 expression was an independent prognostic factor (P = 0.046). Our results indicate that B7-H3 appears to be a useful blood marker for predicting tumor progression in gastric cancer.

Marker expression in circulating cancer cells of pancreatic cancer patients

BACKGROUND

By the time patients are diagnosed with pancreatic cancer, circulating cancer cells probably exist. Therefore, the detection of pancreatic cancer cells in the peripheral circulation could be used to diagnose early pancreatic cancer, which would otherwise not be detected by current imaging methods.

METHODS

The expression levels of h-TERT, CK20, CEA, and C-MET were detected in a model of circulating micrometastasis in pancreatic cancer that were enriched using immune-magnetic separation of the circulating cancer cells. The sensitivity and specificity of the measurements were evaluated. The expression of the above genes was measured in the circulating cancer cells of pancreatic cancer patients. We compared their expression rate in pancreatic cancer patients at different stages to screen for the indicator with highest sensitivity and specificity for the detection of circulating pancreatic cancer cells.

RESULTS

Immuno-magnetic nanoparticles combined with RT-PCR enabled the detection of one tumor cell per 1×10(7) peripheral blood mononuclear cells. The positive expression rates of C-MET, h-TERT, CK20, and CEA in the pancreatic cancer group were 80% (20/25), 100% (25/25), 84% (21/25), and 80% (20/25), respectively, while in the benign disease control group the rates were 0% (0/15), 0% (0/15), 6.77% (1/15), and 0% (0/15), respectively. There was a significant difference in the positive expression rate between the two groups (P<0.05). The specificity of h-TERT, CEA, and C-MET was higher than that of CK20. The positive expression rate of the four genes was not related to gender, age, tumor size, CA 19-9, or CEA serum levels (P>0.05). However, the positive expression of C-MET, CK20, and CEA closely correlated with tumor stage (P<0.05). Immuno-magnetic nanoparticles combined with RT-PCR were specific and sensitive for the detection of circulating cancer cells.

CONCLUSIONS

The positive expression of C-MET, h-TERT, CK20, and CEA in the circulation of pancreatic patients could be used as an indicator for circulating cancer cells. The combined detection of the four genes improved the specificity and sensitivity to 100%, which may be attributable to the use of immuno-magnetic separation and enrichment of the circulating pancreatic cancer cells. Our results suggest the clinical utility of this approach.

A colorimetric method for detection of K-ras codon 12 point mutations in DNA extracted from tissue and peripheral blood in pancreatic disorders

Molecular-based methods to monitor point mutations require special and expensive equipment unavailable in most hospitals. Colorimetric-based analysis is an ideal platform for K-ras codon 12 gene point mutations because it uses commonly found hospital equipment. The colorimetric assay is sensitive and specific, detecting mutated DNA levels as low as 1% in a wild-type background. Paired genomic DNA extracts of fixed tissue and cellular fractions of peripheral blood are more sensitive and accurate than unpaired samplings. This approach has the potential to improve K-ras point mutation scans as well as to detect micrometastases in circulating tumor cells.

Carcinoembryonic antigen messenger RNA expression in blood predicts recurrence in esophageal cancer

PURPOSE

The clinical significance of isolated tumor cells (ITC) in blood has not been clearly established, particularly during follow-up in cancer patients. We conducted a longitudinal analysis of the relationship between ITC in blood during follow-up and clinicopathologic findings in patients with esophageal squamous cell carcinoma.

EXPERIMENTAL DESIGN

Blood samples obtained from 106 patients were examined by real-time RT-PCR assay targeting carcinoembryonic antigen (CEA) mRNA. Follow-up examination every 3 months after surgery included testing for CEA mRNA and tumor markers, as well as imaging.

RESULTS

Thirty-nine (36.8%) patients were positive for CEA mRNA expression. CEA mRNA positivity significantly correlated with tumor depth, lymph node metastasis, stage, and venous invasion. Recurrent disease was found in 34 of 106 (32.1%) cases. CEA mRNA was found in 28 (76.5%) patients experiencing relapse. Of these 28 patients, the number positive of CEA mRNA before detection by imaging, at the same time of detection by imaging, and after detection by imaging was 18 (52.9%), 8 (23.5%), and 2 (5.9%), respectively. The sensitivity, specificity, positive predictive value, and negative predictive value for CEA mRNA were higher than those for serum CEA or squamous cell carcinoma. Patients positive for CEA mRNA experienced significantly shorter disease-free interval than those with negative CEA mRNA (P < 0.001). According to multivariate analysis, CEA mRNA positivity was an independent factor for disease-free interval.

CONCLUSIONS

Examination of CEA mRNA in peripheral blood during follow-up is useful for early detection of occult recurrence. We believe that CEA mRNA in blood will be a new marker for recurrence in esophageal squamous cell carcinoma.

Haemoglobin, serum albumin and transferrin variants of Bali (Banteng) cattle, Bos (Bibos) javanicus

1. Individual blood samples from 144 Bali (Banteng) cattle [Bos (Bibos) javanicus] in the Northern Territory of Australia and from 61 Bali cross cattle, were examined by zone electrophoresis to determine the variants of haemoglobin, serum albumin and transferrin that are present. 2. Of the common cattle haemoglobin variants (A and B) only variant B occurs in the Bali cattle samples. A second variant, designated CBali, occurs in Bali cattle either as the heterozygote (B CBali) or as the homozygote, the frequencies of occurrence indicating a two-allele system of inheritance without dominance. The CBali cross samples may exhibit the homozygous or heterozygous A variant. 3. The CBali variant has an electrophoretic mobility intermediate between those of the A and B variants at pH 8.6 and 9.1 but closer to B than to A (B greater than C greater than A). It appears to be similar in mobility to the C variants found in Indian Khillan (CKhillan) by Naik, Sukumaran and Sanghvi (Anim. Prodn, 1965 I, 275-277), and in Asian cattle by Oishi, Abe and Namikama (Immunogenet. Lett., 1968 5, 170-173) and Abe, Mogi, Oishi, Tanaka and Suzuki (Proc. XIIth Europ. Conf. Anim. Blood Groups Biochem. Polymorphisms 1972, pp. 225-228), but appreciably different from those in Kenyan and Rhodesian cattle (CRhodesia) found by Braend (Anim. Blood Grps Biochem. Genet., 1971 2, 15-21) and Carr (Rhod. J. agric. Res., 1964 3, 62-62A), respectively. It is also different in mobility from the C variant found by Winter, Mayr, Schleger, Dworak, Krutzler and Burger (Res. vet. Sci., 1984 36, 276-283) in the mithun.(ABSTRACT TRUNCATED AT 250 WORDS)