Biomarkers for early diagnosis of pancreatic cancer

Blood-Based Biomarkers in the Diagnosis and Risk Stratification of Pancreatic Cysts

The use of blood-based biomarkers for the assessment of pancreatic cystic lesions is a rapidly growing field with incredible potential. CA 19-9 remains the only blood-based marker in common use, while many novel biomarkers are in early stages of development and validation. We highlight current work in the fields of proteomics, metabolomics, cell-free DNA/circulating tumor DNA, extracellular vesicles, and microRNA among others, as well as barriers to development and future directions in the work of blood-based biomarkers for pancreatic cystic lesions.

A nucleolin-activated polyvalent aptamer nanoprobe for the detection of cancer cells

Sensitive detection of cancer cells plays a critical role in early cancer diagnosis. Nucleolin, overexpressed on the surface of cancer cells, is regarded as a candidate biomarker for cancer diagnosis. Thus, cancer cells can be detected through the detection of membrane nucleolin. Herein, we designed a nucleolin-activated polyvalent aptamer nanoprobe (PAN) to detect cancer cells. In brief, a long single-stranded DNA with many repeated sequences was synthesized through rolling circle amplification (RCA). Then the RCA product acted as a scaffold chain to combine with multiple AS1411 sequences, which was doubly modified with fluorophore and quenching group, respectively. The fluorescence of PAN was initially quenched. Upon binding to target protein, the conformation of PAN changed, leading to the recovery of fluorescence. The fluorescence signal of cancer cells treated with PAN was much brighter compared with that of monovalent aptamer nanoprobes (MAN) at the same concentration. Furthermore, the binding affinity of PAN to B16 cells was proved to be 30 times higher than that of MAN by calculating the dissociation constants. The results indicated that PAN could specifically detect target cells, and this design concept has potential to become promising in cancer diagnosis.

Extracellular vesicle-derived microRNAs in pancreatic juice as biomarkers for detection of pancreatic ductal adenocarcinoma

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) is usually diagnosed in an advanced stage, with minimal likelihood of long-term survival. Only a small subset of patients are diagnosed with early (T1) disease. Early detection is challenging due to the late onset of symptoms and limited visibility of sub-centimeter cancers on imaging. A novel approach is to support the clinical diagnosis with molecular markers. MicroRNA derived from extracellular vehicles (EVs) in blood has shown promise as a potential biomarker for pancreatic neoplasia, but microRNA derived from pancreatic juice (PJ) may be a more sensitive biomarker, given that is in close contact with ductal cells from which PDAC arises. This study aims to evaluate and compare the performance of PJ- and serum-derived EV-miRNA for the detection of PDAC.

METHODS

PJ was collected from the duodenum during EUS after secretin stimulation from 54 patients with PDAC and 118 non-malignant controls. Serum was available for a subset of these individuals. MiR-16, miR-21, miR-25, miR-155 and miR-210 derived from EVs isolated from PJ and serum were analyzed by qPCR, and serum CA19-9 levels were determined by electrochemiluminescence immunoassay. For statistical analysis, either a Mann-Whitney U test or a Wilcoxon Signed Rank test was performed. ROC curves and AUC were used to assess the sensitivity and specificity of miR expression for PDAC detection.

RESULTS

Expression of EV-miR-21, EV-miR-25 and EV-miR-16 were increased in cases vs controls in PJ, while only EV-miR-210 was increased in serum. The potential to detect PC was good for a combination of PJ EV-miR-21, EV-miR-25, EV-miR-16 and serum miR-210, CA-19-9, with an area under the curve of 0.91, a specificity of 84.2% and a sensitivity of 81.5%.

CONCLUSION

Detection of miRNA from EVs in PJ is feasible. A combined panel of PJ EV-miR-21, EV-miR-25, EV-miR-16, and serum EV-miR-210 and CA19-9 distinguishes cases with PDAC from controls undergoing surveillance with a specificity of 81.5% and sensitivity of 84.2%.

"Depart from evil, and do good": Turning Axl from uncontrolled tumorigenic gene to biomarker for early detection of pancreatic cancer

Attempts to achieve early diagnosis are crucial to improve the outcome of patients with pancreatic ductal adenocarcinoma (PDAC). Here we present a critical evaluation of a recent study unraveling the potential of circulating AXL as a novel blood marker for early detection of PDAC and differential diagnosis from chronic pancreatitis (CP).

Novel insight into pancreatic adenocarcinoma pathogenesis using liquid association analysis

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy associated with a poor prognosis. High-throughput disease-related-gene expression data provide valuable information on gene interaction, which consequently lead to deeper insight about pathogenesis. The co-expression analysis is a common approach that is used to investigate gene interaction. However, such an approach solely is inadequate to reveal the complexity of the gene interaction. The three-way interaction model is known as a novel approach applied to decode the complex relationship between genes.

METHODS

In the current study, the liquid association method was used to capture the statistically significant triplets involved in the PDAC pathogenesis. Subsequently, gene set enrichment and gene regulatory network analyses were performed to trace the biological relevance of the statistically significant triplets.

RESULTS

The results of the current study suggest that "response to estradiol" and "Regulation of T-cell proliferation" are two critical biological processes that may be associated with the PDAC pathogenesis. Additionally, we introduced six switch genes, namely Lamc2, Klk1, Nqo1, Aox1, Tspan1, and Cxcl12, which might be involved in PDAC triggering.

CONCLUSION

In the current study, for the first time, the critical genes and pathways involved in the PDAC pathogenesis were investigated using the three-way interaction approach. As a result, two critical biological processes, as well as six potential biomarkers, were suggested that might be involved in the PDAC triggering. Surprisingly, strong evidence for the biological relevance of our results can be found in the literature.

Deep Learning Improves Pancreatic Cancer Diagnosis Using RNA-Based Variants

For optimal pancreatic cancer treatment, early and accurate diagnosis is vital. Blood-derived biomarkers and genetic predispositions can contribute to early diagnosis, but they often have limited accuracy or applicability. Here, we seek to exploit the synergy between them by combining the biomarker CA19-9 with RNA-based variants. We use deep sequencing and deep learning to improve differentiating pancreatic cancer and chronic pancreatitis. We obtained samples of nucleated cells found in peripheral blood from 268 patients suffering from resectable, non-resectable pancreatic cancer, and chronic pancreatitis. We sequenced RNA with high coverage and obtained millions of variants. The high-quality variants served as input together with CA19-9 values to deep learning models. Our model achieved an area under the curve (AUC) of 96% in differentiating resectable cancer from pancreatitis using a test cohort. Moreover, we identified variants to estimate survival in resectable cancer. We show that the blood transcriptome harbours variants, which can substantially improve noninvasive clinical diagnosis.

Pancreatic Cancer Insights: Optimization of the Diagnostic Capacity of Tumor Biomarkers

OBJECTIVE

Pancreatic cancer (PC) is one of the deadliest malignancies. The aim of this study was to determine the usefulness of the carbohydrate antigen 19.9 (CA19.9)/ carcinoembryonic antigen (CEA) ratio as a diagnostic tool.

METHODS

This was a retrospective observational study (2015-2019), including laboratory requests with increased CA19.9 and CEA but no previous neoplasia. Receiver operating characteristic (ROC) curve analyses were performed for the CA19.9/CEA ratio and for CA19.9 and CEA alone for the detection of PC, and cutoff values for all strategies were selected separately and in combination.

RESULTS

A total of 373 individuals were included. The area under the curve (AUC) for CA19.9/CEA was 0.872, whereas the AUC for CA19.9 was 0.847 and for CEA was 0.554. Cutoff values with the greatest diagnostic power were CA19.9/CEA >40, CA19.9 >1130 U/mL, and CEA > 14.5 U/mL. The combination of CA19.9/CEA > 40 with CA19.9 > 550 U/mL maximized the diagnostic accuracy for PC.

CONCLUSION

Our results highlight the relevance of the measurement of serum CA19.9 and CEA in the detection of PC.

Early detection of pancreatic cancer

Pancreatic ductal adenocarcinoma is most frequently detected at an advanced stage. Such late detection restricts treatment options and contributes to a dismal 5-year survival rate of 3-15%. Pancreatic ductal adenocarcinoma is relatively uncommon and screening of the asymptomatic adult population is not feasible or recommended with current modalities. However, screening of individuals in high-risk groups is recommended. Here, we review groups at high risk for pancreatic ductal adenocarcinoma, including individuals with inherited predisposition and patients with pancreatic cystic lesions. We discuss studies aimed at finding ways of identifying pancreatic ductal adenocarcinoma in high-risk groups, such as among individuals with new-onset diabetes mellitus and people attending primary and secondary care practices with symptoms that suggest this cancer. We review early detection biomarkers, explore the potential of using social media for detection, appraise prediction models developed using electronic health records and research data, and examine the application of artificial intelligence to medical imaging for the purposes of early detection.

Novel Metabolomics Serum Biomarkers for Pancreatic Ductal Adenocarcinoma by the Comparison of Pre-, Postoperative and Normal Samples

Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive human malignancies. The metabolomic approaches are developed to discover the novel biomarkers of PDAC. Methods: 550 preoperative, postoperative PDAC and normal controls (NCs) serums were employed to characterize metabolic alterations in training and validation sets by LC-MS. Results: The results of PLS-DA analysis indicated that three groups could be distinguished clearly and the post-PDAC group is adjacent to a normal group as compared with pre-PDAC group. Further results showed that histidinyl-lysine significantly increased whereas docosahexaenoic acid and LysoPC (14:0) decreased in pre-PDAC patients as compared with NCs. And these three markers had a significant tendency to recover after tumor resection. The validation set results revealed that for CA19-9 negative patients, 92.3% (12/13) of them can be screened using these three metabolites. The combination of these markers could significantly improve the diagnostic performance for PDAC, with higher sensitivity (0.93), specificity (0.92) and AUC (0.97). Moreover, network and pathways analyses explored the latent relationship among differential metabolites. The glycerolipid metabolism and primary bile acid synthesis showed variation in network and pathway analysis. Conclusions: These three markers combined with CA199 displayed high sensitivity and specificity for detecting PDAC patients from NCs. The results indicated that these three metabolites could be regarded as potential biomarkers to distinguish PDAC from NCs.

Evaluation of serum MUC5AC in combination with CA19-9 for the diagnosis of pancreatic cancer

Background

Pancreatic cancer (PC) is a highly aggressive tumor with a poor prognosis that lacks specific diagnostic markers. Mucin 5AC (MUC5AC) is a member of the mucin family, a heterogeneous group of high molecular weight, heavily glycosylated proteins that could be either membrane-bound or secreted. This multi-central study is to evaluate the performance of serum MUC5AC in combination with carbohydrate antigen 19-9 (CA19-9) for the diagnosis of PC in Asian.

Methods

Sixty-one patients with PC (comprised of early pancreatic cancer [n = 30] and late pancreatic cancer [n = 31] patients), 29 benign control, 35 choledocholithiasis, 25 chronic pancreatitis, and 34 healthy controls, were recruited from two hospitals. Serum levels of MUC5AC were evaluated by commercial ELISA kits. CA19-9 was measured by chemiluminescence immunoassay. The cutoff value of MUC5AC was determined based on optimal sensitivity and specificity.

Results

Serum MUC5AC in patients with PC (210.1 [100.5–423.8] ng/mL) presented higher levels than those in controls. The combined biomarker panel (MUC5AC and CA19-9) presented better performance and improved specificity to differentiate PC from controls (AUC 0.894; 95% CI (0.844–0.943), sensitivity 0.738, specificity 0.886) than CA19-9 (p = 0.043) or MUC5AC alone (p = 0.010); however, the latter two had no difference (p = 0.824).

Conclusions

Serum MUC5AC is a potential biomarker for PC. The combination with CA19-9 presents improved specificity and better performance.

Dkk1 involvement and its potential as a biomarker in pancreatic ductal adenocarcinoma

Dickkopf-1 (Dkk1)'s dysregulation has been implicated in the pathogenesis of a variety of cancers. It is part of the Dkk family of proteins that includes Dkk2, Dkk3 and Dkk4. This family of secreted proteins shares similar conserved cysteine domains and inhibits the Wnt/b-catenin pathway by causing proteasomal B-catenin degradation, inducing apoptosis, and preventing cell proliferation. Pancreatic ductal adenocarcinoma (PDAC) is the 4th leading cause of cancer mortality in the United States due to the late stage of diagnosis and the limited effectiveness of current therapy. Dkk1 is found increased in PADC patients' specimens and serum. Dkk1 can be a promising biomarker specific to PDAC, which has the potential to increase PDAC survival rates through improving early stage detection and monitoring progression compared to current biomarker gold standards. In addition, recent studies suggest that Dkk1 could be an excellent target for cancer immunotherapy. Interestingly, Dkk1-CKAP4-PI3K/AKT signal pathway also plays role in pancreatic cancer cell proliferation. In this review, we present the multiple mechanisms of Dkk1 in PDAC studied thus far and explore its function, regulation, and clinical applications in gynecological cancers including pancreatic ductal adenocarcinoma (PDAC), breast, ovarian, cervical, and endometrial cancer. Further research into Dkk1's mechanism and use as a diagnostic tool, alone or in combination with other biomarkers, could prove clinically useful for better understanding the pathology of PDAC and improving its early detection and treatment.

Diagnostic Value of CA 19-9 and Carcinoembryonic Antigen for Pancreatic Cancer: A Meta-Analysis

Background

CA 19-9 and carcinoembryonic antigen (CEA) are widely used for the diagnosis of pancreatic cancer. The purpose of the present study was to compare the diagnostic value of CA 19-9 with CEA for pancreatic cancer.

Methods

The studies were obtained from electronic searches conducted in PubMed, Embase, and Cochrane Library databases until December 2017. The keywords included diagnosis of pancreatic cancer, CA 19-9, and CEA. The ratio of sensitivity, the specificity, the diagnostic odds ratio (DOR), and the summary of the receiver operating characteristic (SROC) with regard to CA 19-9 and CEA were measured using the random effects model. The current study included 13 studies that comprised 4,537 participants and 1,277 patients with pancreatic cancer.

Results

The levels of CA 19-9 for use for the detection of pancreatic cancer were associated with higher sensitivity (ratio of sensitivity: 1.54; 1.31–1.81; P < 0.001), DOR (DOR: 3.50; 95% CI: 2.24–5.45; P < 0.001), and AUC (ratio of AUC: 1.24; 95% CI: 1.15–1.33; P < 0.001) compared with the variable CEA, while no significant difference between CA 19-9 and CEA was noted with regard to specificity (ratio of specificity: 0.97; 95% CI: 0.89–1.06; P = 0.517). The findings of the subgroup analyses suggested that different cutoff values of CA 19-9 and CEA might affect the diagnostic value.

Conclusions

The findings of the present study indicated that CA 19-9 levels were associated with higher sensitivity, DOR, and AUC compared with the corresponding levels of CEA with regard to the diagnosis of pancreatic cancer.

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.

Profile of exhaled-breath volatile organic compounds to diagnose pancreatic cancer

Background

Pancreatic cancer has a very poor prognosis as most patients are diagnosed at an advanced stage when curative treatments are not possible. Breath volatile organic compounds (VOCs) have shown potential as novel biomarkers to detect cancer. The aim of the study was to quantify differences in exhaled breath VOCs of patients with pancreatic cancers compared with cohorts without cancer.

Methods

Patients were recruited to an initial development cohort and a second validation cohort. The cancer group included patients with localized and metastatic cancers, whereas the control group included patients with benign pancreatic disease or normal pancreas. The reference test for comparison was radiological imaging using abdominal CT, ultrasound imaging or endoscopic ultrasonography, confirmed by histopathological examination as appropriate. Breath was collected from the development cohort with steel bags, and from the validation cohort using the ReCIVA™ system. Analysis was performed using gas chromatography–mass spectrometry.

Results

A total of 68 patients were recruited to the development cohort (25 with cancer, 43 no cancer) and 64 to the validation cohort (32 with cancer, 32 no cancer). Of 66 VOCs identified, 12 were significantly different between groups in the development cohort on univariable analysis. Receiver operating characteristic (ROC) curve analysis using significant volatile compounds and the validation cohort produced an area under the curve of 0·736 (sensitivity 81 per cent, specificity 58 per cent) for differentiating cancer from no cancer, and 0·744 (sensitivity 70 per cent, specificity 74 per cent) for differentiating adenocarcinoma from no cancer.

Conclusion

Breath VOCs may distinguish patients with pancreatic cancer from those without cancer.

Imaging of Claudin-4 in Pancreatic Ductal Adenocarcinoma Using a Radiolabelled Anti-Claudin-4 Monoclonal Antibody

PURPOSE

Despite its widespread use, the positron emission tomography (PET) radiotracer 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) has been shown in clinical settings to be ineffective for improving early diagnosis of pancreatic ductal adenocarcinoma (PDAC). A promising biomarker for PDAC detection is the tight junction protein claudin-4. The purpose of this study was to evaluate a new single-photon emission computed tomography (SPECT) imaging agent, [111In]anti-claudin-4 mAb, with regard to its ability to allow visualisation of claudin-4 in a xenograft and a genetically engineered mouse model of PDAC.

PROCEDURES

The ability of [111In]anti-claudin-4 mAb to selectively target claudin-4 was assessed using two human xenograft tumour models with differential claudin-4 status in mice. [111In]anti-claudin-4 mAb was also used to detect PDAC development in genetically engineered KPC mice. The PDAC status of these mice was confirmed with [18F]FDG-PET, magnetic resonance imaging (MRI), histology, and immunofluorescence microscopy.

RESULTS

High uptake of [111In]anti-claudin-4 mAb was observed in PDAC xenografts in mice, reaching 16.9 ± 4.5 % of injected dose per gram (% ID/g) at 72 h post-injection. This uptake was mediated specifically by the expression of claudin-4. Uptake of [111In]anti-claudin-4 mAb also enabled clear visualisation of spontaneous PDAC formation in KPC mice.

CONCLUSIONS

[111In]anti-claudin-4 mAb allows non-invasive detection of claudin-4 upregulation during development of PDAC and could potentially be used to aid in the early detection and characterisation of this malignancy.

Proteomic biomarkers in body fluids associated with pancreatic cancer

Pancreatic cancer (PC) is a highly malignant disease that represents the fourth leading cancer-related death worldwide. There has been very little improvement in survival rates over recent years, and surgical resection remains the only reliable curative approach. Factors that contribute to this dismal prognosis for PC include its rapid progression and invasion, the absence of specific symptoms, and the little impact of available chemotherapy. Importantly, the management of this malignancy is also limited by the lack of highly specific and sensitive biomarkers for its diagnosis and follow-up, and their identification is therefore considered a promising strategy to improve outcomes in these patients. Numerous translational studies have explored the usefulness of body fluids as a non-invasive source of PC-specific biomarkers, and innovations in proteomic methods and technologies have provided a myriad of protein biomarkers for different cancers. The adoption of a proteomic approach has improved understanding of the biology of PC and contributed to the potential identification of protein biomarkers for this disease. This review considers the most recent research efforts to develop novel proteomic biomarkers in body fluids for PC.

Analysis of sialyl-Lewis x on MUC5AC and MUC1 mucins in pancreatic cancer tissues

Pancreatic adenocarcinoma (PDAC) lacks efficient biomarkers. Mucins are glycoproteins that can carry aberrant glycosylation in cancer. Our objective was to identify cancer-related glycan epitopes on MUC1 and MUC5AC mucins in PDAC as potential biomarkers. We have analysed the tumour-associated carbohydrate antigens sialyl-Lewis x (SLe^x) and sialyl-Tn (STn) on MUC1 and MUC5AC in PDAC tissues. The selected cohort for this study consisted of twenty-one PDAC tissues positive for SLe^x antigen and three normal pancreas specimens as controls. STn expression was shown in 76% of the PDAC tissues. MUC1 and MUC5AC were detected in 90% of PDAC tissues. We performed in situ proximity ligation assay combining antibodies against mucins and glycan epitopes to identify specific mucin glycoforms. MUC1-SLe^x and MUC5AC-SLe^x were found in 68% and 84% respectively, of the mucin expressing PDAC tissues, while STn hardly colocalized with any of the evaluated mucins. Further analysis by Western blot of MUC5AC and SLe^x in eight PDAC tissue lysates showed that six out of eight cases were positive for both markers. Moreover, immunoprecipitation of MUC5AC from positive PDAC tissues and subsequent SLe^x immunodetection confirmed the presence of SLe^x on MUC5AC. Altogether, MUC5AC-SLe^x glycoform is present in PDAC and can be regarded as potential biomarker.

Metabolic biomarker signature to differentiate pancreatic ductal adenocarcinoma from chronic pancreatitis

OBJECTIVE

Current non-invasive diagnostic tests can distinguish between pancreatic cancer (pancreatic ductal adenocarcinoma (PDAC)) and chronic pancreatitis (CP) in only about two thirds of patients. We have searched for blood-derived metabolite biomarkers for this diagnostic purpose.

DESIGN

For a case-control study in three tertiary referral centres, 914 subjects were prospectively recruited with PDAC (n=271), CP (n=282), liver cirrhosis (n=100) or healthy as well as non-pancreatic disease controls (n=261) in three consecutive studies. Metabolomic profiles of plasma and serum samples were generated from 477 metabolites identified by gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry.

RESULTS

A biomarker signature (nine metabolites and additionally CA19-9) was identified for the differential diagnosis between PDAC and CP. The biomarker signature distinguished PDAC from CP in the training set with an area under the curve (AUC) of 0.96 (95% CI 0.93-0.98). The biomarker signature cut-off of 0.384 at 85% fixed specificity showed a sensitivity of 94.9% (95% CI 87.0%-97.0%). In the test set, an AUC of 0.94 (95% CI 0.91-0.97) and, using the same cut-off, a sensitivity of 89.9% (95% CI 81.0%-95.5%) and a specificity of 91.3% (95% CI 82.8%-96.4%) were achieved, successfully validating the biomarker signature.

CONCLUSIONS

In patients with CP with an increased risk for pancreatic cancer (cumulative incidence 1.95%), the performance of this biomarker signature results in a negative predictive value of 99.9% (95% CI 99.7%-99.9%) (training set) and 99.8% (95% CI 99.6%-99.9%) (test set). In one third of our patients, the clinical use of this biomarker signature would have improved diagnosis and treatment stratification in comparison to CA19-9.

New developments in the early diagnosis of pancreatic cancer

Pancreatic cancer is an aggressive carcinoma of the digestive system and radical resection, which is available to very few patients, is the only possibility for cure. Since therapeutic choices are limited at the advanced stage, screening and early diagnostic tools are indispensable for a better prognosis. Areas covered: This review illustrates serologic and imaging examinations, and carbohydrate antigens, microRNAs, methylation biomarkers, molecules in exosomes, ultrasound, computed tomography, magnetic resonance imaging, positron emission tomography and endoscopic retrograde cholangiopancreatography, among other topics. No matter which approach is used, the accuracy of early diagnosis is extremely low. Combining different methods greatly improves the accuracy of early diagnosis. This review was conducted utilizing PubMed with key search words pancreatic cancer, early diagnosis, biomarkers and imaging. Expert commentary: Appropriate combination of biomarkers and imaging technologies will become standard practice in the future. Because the incidence of and mortality from pancreatic cancer is rising, further study of new approaches for the early detection of pancreatic tumors is essential.

Salivary biomarkers in cancer detection

Cancer is the second most common cause of death in the USA. Its symptoms are often not specific and absent, until the tumors have already metastasized. Therefore, there is an urgent demand for developing rapid, highly accurate and noninvasive tools for cancer screening, early detection, diagnostics, staging and prognostics. Saliva as a multi-constituent oral fluid comprises secretions from the major and minor salivary glands, extensively supplied by blood. Molecules such as DNAs, RNAs, proteins, metabolites, and microbiota, present in blood, could be also found in saliva. Recently, salivary diagnostics has drawn significant attention for the detection of specific biomarkers, since the sample collection and processing are simple, cost-effective, and precise and do not cause patient discomfort. Here, we review recent salivary candidate biomarkers for systemic cancers by dividing them according to their origin into: genomic, transcriptomic, proteomic, metabolomic and microbial types.

Pancreatic cancer stem cell markers and exosomes - the incentive push

Pancreatic cancer (PaCa) has the highest death rate and incidence is increasing. Poor prognosis is due to late diagnosis and early metastatic spread, which is ascribed to a minor population of so called cancer stem cells (CSC) within the mass of the primary tumor. CSC are defined by biological features, which they share with adult stem cells like longevity, rare cell division, the capacity for self renewal, differentiation, drug resistance and the requirement for a niche. CSC can also be identified by sets of markers, which for pancreatic CSC (Pa-CSC) include CD44v6, c-Met, Tspan8, alpha6beta4, CXCR4, CD133, EpCAM and claudin7. The functional relevance of CSC markers is still disputed. We hypothesize that Pa-CSC markers play a decisive role in tumor progression. This is fostered by the location in glycolipid-enriched membrane domains, which function as signaling platform and support connectivity of the individual Pa-CSC markers. Outside-in signaling supports apoptosis resistance, stem cell gene expression and tumor suppressor gene repression as well as miRNA transcription and silencing. Pa-CSC markers also contribute to motility and invasiveness. By ligand binding host cells are triggered towards creating a milieu supporting Pa-CSC maintenance. Furthermore, CSC markers contribute to the generation, loading and delivery of exosomes, whereby CSC gain the capacity for a cell-cell contact independent crosstalk with the host and neighboring non-CSC. This allows Pa-CSC exosomes (TEX) to reprogram neighboring non-CSC towards epithelial mesenchymal transition and to stimulate host cells towards preparing a niche for metastasizing tumor cells. Finally, TEX communicate with the matrix to support tumor cell motility, invasion and homing. We will discuss the possibility that CSC markers are the initial trigger for these processes and what is the special contribution of CSC-TEX.

Application of a Serum Protein Signature for Pancreatic Cancer to Separate Cases from Controls in a Pancreatic Surveillance Cohort

BACKGROUND

Pancreatic cancer (PC) surveillance is currently offered to individuals with a genetic predisposition to PC, but routinely used radiological screening modalities are not entirely reliable in detecting early-stage PC or its precursor lesions. We recently identified a discriminating PC biomarker signature in a sporadic patient cohort. In this study, we investigated if protein profiling can accurately distinguish PC from non-PC in a pancreatic surveillance cohort of genetically predisposed individuals.

METHODS

Serum samples of 66 individuals with a CDKN2A germline mutation who participated in the pancreatic surveillance program (5 cases, 61 controls) were obtained following a standardized protocol. After sample clean-up, peptide and protein profiles were obtained on an ultrahigh-resolution matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry platform. A discriminant score for each sample was calculated with a previously designed prediction rule, and the median discriminant scores of cases and controls were compared. Individuals with precursor lesions of PC (n = 4) and individuals with a recent diagnosis of melanoma (n = 4) were also separately considered.

RESULTS

Cases had a higher median discriminant score than controls (0.26 vs 0.016; P = .001). The only individual with pathologically confirmed precursor lesions of PC could also be clearly distinguished from controls, and having a (recent) medical history of melanoma did not influence the protein signatures.

CONCLUSIONS

Peptide and protein signatures are able to accurately distinguish PC cases from controls in a pancreatic surveillance setting. Mass spectrometry-based protein profiling therefore seems to be a promising candidate for implementation in the pancreatic surveillance program as an additional screening modality.

Decreased Serum Thrombospondin-1 Levels in Pancreatic Cancer Patients Up to 24 Months Prior to Clinical Diagnosis: Association with Diabetes Mellitus

PURPOSE

Identification of serum biomarkers enabling earlier diagnosis of pancreatic ductal adenocarcinoma (PDAC) could improve outcome. Serum protein profiles in patients with preclinical disease and at diagnosis were investigated.

EXPERIMENTAL DESIGN

Serum from cases up to 4 years prior to PDAC diagnosis and controls (UKCTOCS,n= 174) were studied, alongside samples from patients diagnosed with PDAC, chronic pancreatitis, benign biliary disease, type 2 diabetes mellitus, and healthy subjects (n= 298). Isobaric tags for relative and absolute quantification (iTRAQ) enabled comparisons of pooled serum from a test set (n= 150). Validation was undertaken using multiple reaction monitoring (MRM) and/or Western blotting in all 472 human samples and samples from a KPC mouse model.

RESULTS

iTRAQ identified thrombospondin-1 (TSP-1) as reduced preclinically and in diagnosed samples. MRM confirmed significant reduction in levels of TSP-1 up to 24 months prior to diagnosis. A combination of TSP-1 and CA19-9 gave an AUC of 0.86, significantly outperforming both markers alone (0.69 and 0.77, respectively;P< 0.01). TSP-1 was also decreased in PDAC patients compared with healthy controls (P< 0.05) and patients with benign biliary obstruction (P< 0.01). Low levels of TSP-1 correlated with poorer survival, preclinically (P< 0.05) and at clinical diagnosis (P< 0.02). In PDAC patients, reduced TSP-1 levels were more frequently observed in those with confirmed diabetes mellitus (P< 0.01). Significantly lower levels were also observed in PDAC patients with diabetes compared with individuals with type 2 diabetes mellitus (P= 0.01).

CONCLUSIONS

Circulating TSP-1 levels decrease up to 24 months prior to diagnosis of PDAC and significantly enhance the diagnostic performance of CA19-9. The influence of diabetes mellitus on biomarker behavior should be considered in future studies.

Improved Pancreatic Adenocarcinoma Diagnosis in Jaundiced and Non-Jaundiced Pancreatic Adenocarcinoma Patients through the Combination of Routine Clinical Markers Associated to Pancreatic Adenocarcinoma Pathophysiology

BACKGROUND

There is still no reliable biomarker for the diagnosis of pancreatic adenocarcinoma. Carbohydrate antigen 19-9 (CA 19-9) is a tumor marker only recommended for pancreatic adenocarcinoma follow-up. One of the clinical problems lies in distinguishing between this cancer and other benign pancreatic diseases such as chronic pancreatitis. In this study we will assess the value of panels of serum molecules related to pancreatic cancer physiopathology to determine whether alone or in combination could help to discriminate between these two pathologies.

METHODS

CA 19-9, carcinoembryonic antigen (CEA), C-reactive protein, albumin, insulin growth factor-1 (IGF-1) and IGF binding protein-3 were measured using routine clinical analyzers in a cohort of 47 pancreatic adenocarcinoma, 20 chronic pancreatitis and 15 healthy controls.

RESULTS

The combination of CA 19-9, IGF-1 and albumin resulted in a combined area under the curve (AUC) of 0.959 with 93.6% sensitivity and 95% specificity, much higher than CA 19-9 alone. An algorithm was defined to classify the patients as chronic pancreatitis or pancreatic cancer with the above specificity and sensitivity. In an independent validation group of 20 pancreatic adenocarcinoma and 13 chronic pancreatitis patients, the combination of the four molecules classified correctly all pancreatic adenocarcinoma and 12 out of 13 chronic pancreatitis patients.

CONCLUSIONS

Although this panel of markers should be validated in larger cohorts, the high sensitivity and specificity values and the convenience to measure these parameters in clinical laboratories shows great promise for improving pancreatic adenocarcinoma diagnosis.

International Association of Pancreatology (IAP)/European Pancreatic Club (EPC) consensus review of guidelines for the treatment of pancreatic cancer

BACKGROUND

Pancreatic cancer is one of the most devastating diseases with an extremely high mortality. Medical organizations and scientific societies have published a number of guidelines to address active treatment of pancreatic cancer. The aim of this consensus review was to identify where there is agreement or disagreement among the existing guidelines and to help define the gaps for future studies.

METHODS

A panel of expert pancreatologists gathered at the 46th European Pancreatic Club Meeting combined with the 18th International Association of Pancreatology Meeting and collaborated on critical reviews of eight English language guidelines for the clinical management of pancreatic cancer. Clinical questions (CQs) of interest were proposed by specialists in each of nine areas. The recommendations for the CQs in existing guidelines, as well as the evidence on which these were based, were reviewed and compared. The evidence was graded as sufficient, mediocre or poor/absent.

RESULTS

Only 4 of the 36 CQs, had sufficient evidence for agreement. There was also agreement in five additional CQs despite the lack of sufficient evidence. In 22 CQs, there was disagreement regardless of the presence or absence of evidence. There were five CQs that were not addressed adequately by existing guidelines.

CONCLUSION

The existing guidelines provide both evidence- and consensus-based recommendations. There is also considerable disagreement about the recommendations in part due to the lack of high level evidence. Improving the clinical management of patients with pancreatic cancer, will require continuing efforts to undertake research that will provide sufficient evidence to allow agreement.