K-ras mutations in the duodenal fluid of patients with pancreatic carcinoma

MicroRNA-20a in extracellular vesicles derived from duodenal fluid is a possible biomarker for pancreatic ductal adenocarcinoma

Background

Pancreatic ductal adenocarcinoma (PDAC) has a high mortality rate owing to its late diagnosis and aggression. In addition, there are relatively few minimally invasive screening methods for the early detection of PDAC, making the identification of biomarkers for this disease a critical priority. Recent studies have reported that microRNAs in extracellular vesicles (EV-miRs) from bodily fluids can be useful for the diagnosis of PDACs. Given this, we designed this study to evaluate the utility of cancer EVs extracted from duodenal fluid (DF) and their resident EV-miRs as potential biomarkers for the detection of PDAC.

Methods

EV-miRs were evaluated and identified in the supernatants of various pancreatic cancer cell lines (Panc-1, SUIT2, and MIAPaca2), human pancreatic duct epithelial cells, and the DF from patients with PDAC and healthy controls. EVs were extracted using ultracentrifugation and the relative expression of EV-miR-20a was quantified.

Results

We collected a total of 34 DF samples (27 PDAC patients and seven controls) for evaluation and our data suggest that the relative expression levels of EV-miR-20a were significantly higher in patients with PDAC than in controls (p = 0.0025). In addition, EV-miR-20a expression could discriminate PDAC from control patients regardless of the location of the tumor with an area under the curve values of 0.88 and 0.88, respectively.

Conclusions

We confirmed the presence of EVs in the DF and suggest that the expression of EV-miR-20a in these samples may act as a potential diagnostic biomarker for PDAC.

Pre-Operative Imaging and Pathological Diagnosis of Localized High-Grade Pancreatic Intra-Epithelial Neoplasia without Invasive Carcinoma

Pancreatic ductal adenocarcinoma (PDAC) arises from precursor lesions, such as pancreatic intra-epithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN). The prognosis of high-grade precancerous lesions, including high-grade PanIN and high-grade IPMN, without invasive carcinoma is good, despite the overall poor prognosis of PDAC. High-grade PanIN, as a lesion preceding invasive PDAC, is therefore a primary target for intervention. However, detection of localized high-grade PanIN is difficult when using standard radiological approaches. Therefore, most studies of high-grade PanIN have been conducted using specimens that harbor invasive PDAC. Recently, imaging characteristics of high-grade PanIN have been revealed. Obstruction of the pancreatic duct due to high-grade PanIN may induce a loss of acinar cells replaced by fibrosis and lobular parenchymal atrophy. These changes and additional inflammation around the branch pancreatic ducts (BPDs) result in main pancreatic duct (MPD) stenosis, dilation, retention cysts (BPD dilation), focal pancreatic parenchymal atrophy, and/or hypoechoic changes around the MPD. These indirect imaging findings have become important clues for localized, high-grade PanIN detection. To obtain pre-operative histopathological confirmation of suspected cases, serial pancreatic-juice aspiration cytologic examination is effective. In this review, we outline current knowledge on imaging characteristics of high-grade PanIN.

Role of Ancillary Techniques in Biliary Cytopathology Specimens

Biliary brushing cytology has become the standard of practice for the investigation of strictures of the biliary and pancreatic duct systems. The methodology however has a limitation in that it has low diagnostic sensitivity when only cytologic evaluation is used. A number of testing methodologies have been applied to brushing specimens in an attempt to improve overall sensitivity without loss of specificity. These have included DNA ploidy analysis, immunocytochemistry, individual gene mutational analysis, fluorescence in-situ hybridization (FISH), and next generation sequencing (NGS). Currently, FISH coupled with routine cytology appears to be the method of choice for improving diagnostic sensitivity. NGS shows significant promise for improvement of diagnostic sensitivity.

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.

S100P in Duodenal Fluid Is a Useful Diagnostic Marker for Pancreatic Ductal Adenocarcinoma

OBJECTIVES

The development of an effective screening method for pancreatic ductal adenocarcinoma (PDAC) is of paramount importance. This study assessed the diagnostic utility in pancreatic diseases of duodenal markers during upper gastrointestinal endoscopy (GIE) or endoscopic ultrasonography.

METHODS

This study prospectively enrolled 299 consecutive participants, including 94 patients with PDACs, 144 patients with other pancreatic diseases, and 61 normal individuals as control subjects. All subjects underwent upper GIE or endoscopic ultrasonography either at Kyushu University Hospital (Fukuoka, Japan) or the Mayo Clinic (Jacksonville, Fla) from October 2011 to July 2014. Duodenal fluid (DF) was collected without secretin stimulation and of carcinoembryonic antigen and S100 calcium-binding protein P (S100P) concentrations were measured.

RESULTS

Concentrations of S100P in DF were significantly higher in patients with PDAC and chronic pancreatitis than in control subjects (P < 0.01). A logistic regression model that included age found that the sensitivity and specificity of S100P concentration in diagnosing stages 0/IA/IB/IIA PDAC were 85% and 77%, respectively, with an area under the receiver operating characteristic curve of 0.82. Carcinoembryonic antigen concentrations in DF of patients with pancreatic disease did not differ significantly from control subjects.

CONCLUSIONS

Analysis of S100P concentration in DF, in combination with routine screening upper GIE, may facilitate the detection of PDAC.

Detection of K-ras gene mutations in feces by magnetic nanoprobe in patients with pancreatic cancer: A preliminary study

The present study aimed to investigate the feasibility and effectiveness of detecting K-ras mutation by using magnetic nanoparticles in fecal samples of patients with pancreatic cancer at different stages. The novel methodology of K-ras mutation detection was compared to the existing methodology of cancer antigen (CA)19-9 examination. Patients with pancreatic cancer (n=88), pancreatic benign diseases who displayed chronic pancreatitis (n=35), pancreatic mucinous cyst neoplasms (n=10) and pancreatic serous cyst (n=9) admitted to the Department of Surgery, Jiaxing Second Hospital were enrolled in the present study. Fecal samples were collected from all patients, DNA was extracted and magnetic nanoprobe was then used to detect K-ras mutation. The results obtained using the novel magnetic nanoprobe detection technique showed a K-ras mutation rate of 81.8% (72/88) in the patients with pancreatic cancer and 18.5% (10/54) in patients with pancreatic benign diseases. In patients with pancreatic cancer, the K-ras mutation rate was comparable in stages I + IIA and IIB + III + IV (78.9 vs. 84.0%; P>0.05). The sensitivity and specificity of K-ras mutation for detection of pancreatic cancer was 81.8 and 81.5%, respectively. Sixty-eight pancreatic cancer patients had >37 U/ml CA99 with a sensitivity and specificity for pancreatic cancer detection of 77.3 and 77.8%, which was not significantly lower than detection by the fecal K-ras mutations (P>0.05). Combinational detection of fecal K-ras mutations and serum CA19-9 significantly increased the sensitivity regarding pancreatic cancer detection to 97.7% (P<0.05), while the specificity was not enhanced (80.9%; P>0.05) compared with fecal K-ras mutations or CA19-9 alone. The findings showed that the magnetic nanoprobe is able to detect fecal K-ras mutations in different stages of pancreatic cancer, with comparable sensitivity and specificity to CA19-9 examination for differentiating pancreatic cancer. Furthermore, combined detection of CA19-9 and K-ras mutations has enhanced sensitivity compared with CA19-9 alone.

Metallacarboranes as tunable redox potential electrochemical indicators for screening of gene mutation

The substitution of hydrogen with chlorine in the metallacarborane [3,3-Fe(1,2-closo-C2B9H11)2]- cluster modulates the formal potential of the Fe3+/Fe2+ redox couple, shifting it to a more positive value. Hence, very similar redox probes with a wide range of formal potentials, ranging from negative to positive values, are available. Thus, we have achieved the synthesis and studied the electrochemical behaviour of the sodium salt of [3,3-Fe(8,9,12-Cl3-1,2-closo-C2B9H8)2]- in aqueous media. This strategy allows tuning of the redox potential of the [3,3-Fe(1,2-closo-C2B9H11)2]- framework with a minor change in its shape and dimensions. We also describe the interaction of the prepared [3,3-Fe(8,9,12-Cl3-1,2-closo-C2B9H8)2]- and the pristine [3,3-Fe(1,2-closo-C2B9H11)2]- with DNA. These studies have been carried out not only with DNA in solution but also with DNA immobilized on screen-printed gold electrodes. The results obtained point to a strong interaction between the metallacarboranes and DNA, to a different extent with single stranded DNA (ssDNA) compared to double stranded DNA (dsDNA). This property makes them selective and wide-ranging potential electrochemical indicators of hybridization. The suitability of these new redox indicators for selective DNA biosensor development has been probed by the direct detection of two different mutations associated with cystic fibrosis in PCR amplicons extracted from blood cells.

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.

International consensus on the management of intraductal papillary mucinous neoplasm of the pancreas

International consensus guidelines for the management of intraductal papillary mucinous neoplasm (IPMN) of the pancreas revised in 2012 (Fukuoka consensus) seem to be accepted well worldwide. Division of various factors to predict malignant transformation into two categories, i.e., "high-risk stigmata" and "worrisome features", is also accepted as practically useful for stratifying the risk factors. Our current interest resides in the development of noninvasive and/or invasive pancreatic cancer in areas of the pancreas distinct from IPMN. Invasive pancreatic cancers derived from and concomitant with IPMN should be distinguished to clarify the incidence of each entity, although some more definitive method for differentiation has to be devised in some cases where histological distinction is obscure. IPMN is a clue to early detection of pancreatic cancer. The optimal surveillance protocol for IPMN on observation should be determined in consideration of both of these different pancreatic cancers.

The early detection of pancreatic cancer: what will it take to diagnose and treat curable pancreatic neoplasia?

Pancreatic cancer is the deadliest of all solid malignancies. Early detection offers the best hope for a cure, but characteristics of this disease, such as the lack of early clinical symptoms, make the early detection difficult. Recent genetic mapping of the molecular evolution of pancreatic cancer suggests that a large window of opportunity exists for the early detection of pancreatic neoplasia, and developments in cancer genetics offer new, potentially highly specific approaches for screening of curable pancreatic neoplasia. We review the challenges of screening for early pancreatic neoplasia, as well as opportunities presented by incorporating molecular genetics into these efforts.

Utilization of ancillary studies in the cytologic diagnosis of biliary and pancreatic lesions: The Papanicolaou Society of Cytopathology Guidelines

The Papanicolaou Society of Cytopathology has developed a set of guidelines for pancreatobiliary cytology including indications for endoscopic ultrasound guided fine needle aspiration, terminology and nomenclature of pancreatobiliary disease, ancillary testing and post-biopsy management. All documents are based on the expertise of the authors, a review of the literature, discussion of the draft document at several national and international meetings and synthesis of selected online comments of the draft document. This document presents the results of these discussions regarding the use of ancillary testing in the cytologic diagnosis of biliary and pancreatic lesions. Currently, fluorescence in-situ hybridization (FISH) appears to be the most clinically relevant ancillary technique for cytology of bile duct strictures. The addition of FISH analysis to routine cytologic evaluation appears to yield the highest sensitivity without loss in specificity. Loss of immunohistochemical staining for the protein product of the SMAD4 gene and positive staining for mesothelin support a diagnosis of ductal adenocarcinoma. Immunohistochemical markers for endocrine and exocrine differentiation are sufficient for a diagnosis of endocrine and acinar tumors. Nuclear staining for beta-catenin supports a diagnosis of solid-pseudopapillary neoplasm. Cyst fluid analysis for amylase and carcinoembryonic antigen aids in the pre-operative classification of pancreatic cysts. A number of gene mutations (KRAS, GNAS, von Hippel-Lindau, RNF43 and CTNNB1) may be of aid in the diagnosis of cystic neoplasms. Other ancillary techniques do not appear to improve diagnostic sensitivity sufficiently to justify their increased costs.

Utilization of ancillary studies in the cytologic diagnosis of biliary and pancreatic lesions: the Papanicolaou Society of Cytopathology guidelines for pancreatobiliary cytology

The Papanicolaou Society of Cytopathology has developed a set of guidelines for pancreatobiliary cytology including indications for endoscopic ultrasound-guided fine-needle aspiration, terminology and nomenclature of pancreatobiliary disease, ancillary testing, and post-biopsy management. All documents are based on the expertise of the authors, a review of the literature, discussions of the draft document at several national and international meetings, and synthesis of selected online comments of the draft document. This document presents the results of these discussions regarding the use of ancillary testing in the cytologic diagnosis of biliary and pancreatic lesions. Currently, fluorescence in situ hybridization (FISH) appears to be the most clinically relevant ancillary technique for cytology of bile duct strictures. The addition of FISH analysis to routine cytologic evaluation appears to yield the highest sensitivity without loss in specificity. Loss of immunohistochemical staining for the protein product of the SMAD4 gene and positive staining for mesothelin support a diagnosis of ductal adenocarcinoma. Immunohistochemical markers for endocrine and exocrine differentiation are sufficient for a diagnosis of endocrine and acinar tumors. Nuclear staining for beta-catenin supports a diagnosis of solid-pseudopapilary neoplasm. Cyst fluid analysis for amylase and carcinoembryonic antigen aids in the preoperative classification of pancreatic cysts. Many gene mutations (KRAS, GNAS, VHL, RNF43, and CTNNB1) may be of aid in the diagnosis of cystic neoplasms. Other ancillary techniques do not appear to improve diagnostic sensitivity sufficiently to justify their increased costs.

Diagnostic accuracy of K-ras mutation for pancreatic carcinoma: a meta-analysis

BACKGROUND

The conventional tests for the diagnosis of early stage pancreatic carcinoma are not acceptable. This meta-analysis is to evaluate the accuracy of K-ras mutation for the diagnosis of pancreatic carcinoma.

DATA SOURCES

A systemic search of all relevant literature was performed in Web of Science, EMBASE, Cochrane Database, and MEDLINE (PubMed as the search engine) prior to June 1, 2011. Thirty-four studies fulfilled the inclusion criteria and data were pooled for analysis.

RESULTS

The pooled estimates for K-ras mutation in diagnosis of pancreatic carcinoma were as follows: sensitivity 0.68 (95% CI: 0.66-0.71), specificity 0.87 (95% CI: 0.85-0.88), positive likelihood ratio 4.54 (95% CI: 3.47-5.94), negative likelihood ratio 0.37 (95% CI: 0.30-0.44) and diagnostic odds ratio 14.90 (95% CI: 10.02-22.15). Summary receiver operating characteristic analysis demonstrated that the maximum joint sensitivity and specificity was 0.79, and the overall area under the curve was 0.86.

CONCLUSIONS

Diagnostic accuracy of K-ras mutation was not superior to that of conventional tests. Therefore, K-ras mutation analysis alone is not recommended for the diagnosis of pancreatic carcinoma.

Detection of single-nucleotide variations by monitoring the blinking of fluorescence induced by charge transfer in DNA

Charge transfer dynamics in DNA: Photo-induced charge separation and charge-recombination dynamics in DNA was assessed by monitoring the blinking of fluorescence. Single nucleotide variations, mismatch and one base deletion, were differentiated based on the length of the off-time of the blinking, which corresponds to the lifetime of the charge-separated state.

A fluorescence light-up Ag nanocluster probe that discriminates single-nucleotide variants by emission color

Rapid and precise screening of small genetic variations, such as single-nucleotide polymorphisms (SNPs), among an individual's genome is still an unmet challenge at point-of-care settings. One crucial step toward this goal is the development of discrimination probes that require no enzymatic reaction and are easy to use. Here we report a new type of fluorescent molecular probe, termed a chameleon NanoCluster Beacon (cNCB), that lights up into different colors upon binding SNP targets. NanoCluster Beacons (NCBs) are collections of a small number of Ag atoms templated on single-stranded DNA that fluoresce strongly when placed in proximity to particular DNA sequences, termed enhancers. Here we show the fluorescence emission color of a NCB can change substantially (a shift of 60-70 nm in the emission maximum) depending upon the alignment between the silver nanocluster and the DNA enhancer sequence. Chameleon NCBs exploit this color shift to directly detect SNPs, based on the fact that different SNPs produce a different alignment between the Ag nanocluster and the enhancer. This SNP detection method has been validated on all single-nucleotide substitution scenarios in three synthetic DNA targets, in six disease-related SNP targets, and in two clinical samples taken from patients with ovarian serous borderline tumors. Samples with single-nucleotide variations can be easily identified by the naked eye under UV excitation, making this method a reliable and low-cost assay with a simple readout format.

Genetics and prevention of pancreatic cancer

BACKGROUND

Pancreatic cancer is an aggressive disease with a poor prognosis. Hereditary factors have been reported in up to 10% of cases of pancreatic cancer. The clinical characteristics and genetic abnormalities have been identified for a proportion of this high-risk group, and the development of preventive strategies for these individuals is now a primary goal of cancer clinicians.

METHODS

A review of the current literature regarding the genetics, screening, and prevention of pancreatic cancer and its precursor lesions was undertaken.

RESULTS

Risk factors for pancreatic cancer include smoking, chronic pancreatitis, and a genetic predisposition. The role of diabetes or a diet high in fat or meat remains unclear. The genetic mutations that accompany pancreatic cancer appear to occur in a temporal sequence, beginning in the earliest of precursor lesions. These mutations are detectable in pancreatic juice and, in conjunction with imaging, form the basis of screening programs for high-risk individuals. Not all precursor lesions will undergo malignant transformation, and testing is currently limited in its ability to determine which lesions will undergo transformation.

CONCLUSIONS

Avoiding tobacco smoking and minimizing risk factors associated with chronic pancreatitis are recommended to reduce the risk of pancreatic cancer. Individuals with a high-risk genetic background require counseling, genetic testing if appropriate (BRCA2 mutation or p16INK4A inactivity) and secondary screening for pancreatic cancer in specialist centers. Risk stratification will improve as more genetic abnormalities causing pancreatic cancer are defined.

Genetic alterations in pancreatic cancer

The diagnosis of pancreatic cancer is devastating for patients and their relatives as the incidence rate is approximately the same as mortality rate. Only a small percentage, which ranges from 0.4% to 4% of patients who have been given this diagnosis, will be alive at five years. At the time of diagnosis, 80% of pancreatic cancer patients have unresectable or metastatic disease. Moreover, the therapeutic alternatives offered by chemotherapy or radiotherapy are few, if not zero. For all these reasons, there is an imperative need of analyzing and understanding the primitive lesions that lead to invasive pancreatic adenocarcinoma. Molecular pathology of these lesions is the key of our understanding of the mechanisms underlying the development of this cancer and will probably help us in earlier diagnosis and better therapeutic results. This review focuses on medical research on pancreatic cancer models and the underlying genetic alterations.

Identifying molecular markers for the early detection of pancreatic neoplasia

Pancreatic cancer is the fourth most common cause of cancer death in the United States. There is a great need for better diagnostic markers of pancreatic neoplasia. Better markers would improve the early diagnosis of pancreatic cancer and allow more patients to undergo curative surgical resection. Identifying individuals at high risk of developing pancreatic cancer and applying markers that could identify precancerous lesions of the pancreas in these individuals could allow such lesions to be resected before the development of pancreatic cancer. As we continue to characterize the genetic, epigenetic, and proteomics alterations that occur in pancreatic cancers and their percursors, better diagnostic markers of pancreatic cancer are expected to follow.

Evaluation of clinical relevance of examining K-ras, p16 and p53 mutations along with allelic losses at 9p and 18q in EUS-guided fine needle aspiration samples of patients with chronic pancreatitis and pancreatic cancer

AIM: To establish an optimum combination of molecular markers resulting in best overall diagnostic sensitivity and specificity for evaluation of suspicious pancreatic mass.

METHODS: Endoscopic ultrasound (EUS)-guided fine needle aspiration cytology (FNA) was performed on 101 consecutive patients (63 males, 38 females, 60 ± 12 years; 81 with subsequently diagnosed pancreatic cancer, 20 with chronic pancreatitis) with focal pancreatic mass. Samples were evaluated on-site by an experienced cytopathologist. DNA was extracted from Giemsa stained cells selected by laser microdissection and the presence of K-ras, p53 and p16 somatic mutations was tested by cycling-gradient capillary electrophoresis (CGCE) and single-strand conformation polymorphism (SSCP) techniques. In addition, allelic losses of tumor suppressor genes p16 (INK4, CDKN2A) and DPC4 (MADH4, SMAD4) were detected by monitoring the loss of heterozygosity (LOH) at 9p and 18q, respectively.

RESULTS: Sensitivity and specificity of EUS-guided FNA were 75% and 85%, positive and negative predictive value reached 100%. The remaining 26% samples were assigned as inconclusive. Testing of molecular markers revealed sensitivity and specificity of 70% and 100% for K-ras mutations (P < 0.001), 24% and 90% for p53 mutations (NS), 13% and 100% for p16 mutations (NS), 85% and 64% for allelic losses at 9p (P < 0.001) and 78% and 57% for allelic losses at 18q (P < 0.05). When tests for different molecular markers were combined, the best results were obtained with K-ras + LOH at 9p (92% and 64%, P < 0.001), K-ras + LOH at 18q (92% and 57%, P < 0.001), and K-ras + LOH 9q + LOH 18q (96% and 43%, P < 0.001). When the molecular markers were used as complements to FNA cytology to evaluate inconclusive samples only, the overall sensitivity of cancer detection was 100% in all patients enrolled in the study.

CONCLUSION: EUS-guided FNA cytology combined with screening of K-ras mutations and allelic losses of tumor suppressors p16 and DPC4 represents a very sensitive approach in screening for pancreatic malignancy. Molecular markers may find its use particularly in cases where FNA cytology has been inconclusive.

Comparison of the novel quantitative ARMS assay and an enriched PCR-ASO assay for K-ras mutations with conventional cytology on endobiliary brush cytology from 312 consecutive extrahepatic biliary stenoses

BACKGROUND

Extrahepatic biliary stenosis (EBS) has malignant and benign causes. Patients with EBS are at risk of having or developing malignancy. Accurate diagnostic tests for early detection and surveillance are needed. The sensitivity of biliary cytology for malignancy is low. K-ras mutation analysis on brush cytology is a valuable adjunct, but specificity is low. A quantitative test for K-ras mutations has been developed: the amplification refractory mutation system (ARMS).

AIM

To assess the test characteristics and additional value of ARMS in diagnosing the cause of EBS.

METHODS

Brush samples from endoscopic retrograde cholangiopancreatography were collected from 312 patients with EBS. K-ras mutation analysis was performed using ARMS-allele specific amplification was coupled with real time fluorescent detection of PCR products. Results were compared with conventional cytology and K-ras mutation analysis using allele specific oligonucleotide (ASO) hybridisation, and evaluated in view of the final diagnosis.

RESULTS

The test characteristics of ARMS and ASO largely agreed. Sensitivity for detecting malignancy was 49% and 42%, specificity 93% and 88%, and positive predictive value (PPV) 96% and 91%, respectively. The sensitivity of ARMS and cytology combined was 71%, and PPV was 93%. The specificity of ARMS could be increased to 100% by setting limits for the false positives, but reduced sensitivity from 49% to 43%.

CONCLUSIONS

ARMS can be considered supplementary to conventional cytology, and comparable to ASO in diagnosing malignant EBS. A specificity of 100% can be achieved with ARMS, which should be considered in the surveillance of patients at risk for pancreatic cancer.

Analysis of genomic DNA alterations and mRNA expression patterns in a panel of human pancreatic cancer cell lines

Genomic alterations influencing the expression and/or activity of tumor suppressors or oncogenes such as KRAS2, CDKN2A, TP53, and DPC4 have been directly implicated in the initiation and progression of human pancreatic adenocarcinoma. In an effort further to systematically characterize the genomic alterations that occur in this disease, we conducted a genome wide analysis of alterations in gene copy number using array-based comparative genomic hybridization (CGH). For this analysis, we utilized a panel of 25 human pancreatic cancer cell lines derived from either primary or metastatic tumors. This panel also included a metastatic progression series of cell lines derived from COLO 357 cells. Array CGH permitted the identification of alterations in the copy number of genes that might participate in the aberrant behavior of pancreatic cancer cells. In addition, the acquisition of invasive and metastatic potential by derivatives of COLO 357 cells was accompanied by additional focal genomic alterations including point mutations and amplification of KRAS2. To complement the array CGH analysis, we also conducted an analysis of mRNA expression patterns in a subset of these cells using cDNA microarrays. By this means, we identified a set of candidate genes, including those regulated by RAS signaling, that may contribute to the process of cancer cell invasion and metastasis. Supplementary material for this article can be found on the Genes, Chromosomes, and Cancer website at http://www.interscience.wiley.com/jpages/1045-2257/suppmat/index.html.

Molecular Markers of Early Pancreatic Cancer

Pancreatic cancer is a deadly disease and the fourth most common cause of cancer death in the United States. Since chemotherapy and radiotherapy have thus far largely failed to significantly improve the survival of patients with pancreatic ductal adenocarcinoma, there is considerable interest in identifying better diagnostic markers of pancreatic neoplasia. Not only could better markers improve the early diagnosis of pancreatic cancer and allow more patients to undergo curative surgical resection, but also could potentially be used for patients at high risk of developing pancreatic cancer to identify precancerous lesions while they are amenable to cure. A wealth of information has recently become available about gene expression, DNA methylation, and proteomics alterations that occur in pancreatic cancers creating hope that better diagnostic markers of pancreatic cancer will be soon forthcoming.

Molecular Diagnosis of Solid and Cystic Lesions of the Pancreas

Pancreatic cancer presents at a clinically advanced stage. Diagnosis often is delayed in those who undergo several negative investigations, and at times, the diagnosis ultimately is made at surgery. Tumor suppressor-linked microsatellite allelic loss analysis appears to improve the diagnostic accuracy of inconclusive cytology specimens. Science, however, still suffers from the lack of a reliable biomarker for the purpose of screening and early detection. The continued study of sera and pancreatic juice hopefully will lead to the discovery of molecular biomarkers capable of diagnosing preclinical disease in at-risk groups.The ability to predict the underlying biologic behavior of pancreatic cystic neoplasia is less than ideal. Tumor suppressor-linked microsatellite allelic loss and telomerase analysis show promise, but they have not been studied extensively. Proteomic analysis of pancreatic cyst fluid, although not yet reported, also may prove valuable in guiding clinical management.

Molecular diagnosis of solid and cystic lesions of the pancreas

Pancreatic cancer presents at a clinically advanced stage. Diagnosis often is delayed in those who undergo several negative investigations, and at times, the diagnosis ultimately is made at surgery. Tumor suppressor-linked microsatellite allelic loss analysis appears to improve the diagnostic accuracy of inconclusive cytology specimens. Science, however, still suffers from the lack of a reliable biomarker for the purpose of screening and early detection. The continued study of sera and pancreatic juice hopefully will lead to the discovery of molecular biomarkers capable of diagnosing pre-clinical disease in at-risk groups. The ability to predict the underlying biologic behavior of pancreatic cystic neoplasia is less than ideal. Tumor suppressor-linked microsatellite allelic loss and telomerase analysis show promise, but they have not been studied extensively. Proteomic analysis of pancreatic cyst fluid, although not yet reported, also may prove valuable in guiding clinical management.

LigAmp for sensitive detection of single-nucleotide differences

We developed the LigAmp assay for sensitive detection and accurate quantification of viruses and cells with single-base mutations. In LigAmp, two oligonucleotides are hybridized adjacently to a DNA template. One oligonucleotide matches the target sequence and contains a probe sequence. If the target sequence is present, the oligonucleotides are ligated together and detected using real-time PCR. LigAmp detected KRAS2 mutant DNA at 0.01% in mixtures of different cell lines. KRAS2 mutations were also detected in pancreatic duct juice from patients with pancreatic cancer. LigAmp detected the K103N HIV-1 drug resistance mutation at 0.01% in plasmid mixtures and at approximately 0.1% in DNA amplified from plasma HIV-1. Detection in both systems is linear over a broad dynamic range. Preliminary evidence indicates that reactions can be multiplexed. This assay may find applications in the diagnosis of genetic disorders and the management of patients with cancer and infectious diseases.

p53 and DPC4 alterations in the bile of patients with pancreatic carcinoma

INTRODUCTION

Pancreatic cancer is still predominantly diagnosed in advanced stages, and 85%-90% of patients are not eligible for surgery at diagnosis. This is mainly due to the great difficulty in detecting the tumour at an early stage and presently no satisfactory results have been obtained to overcome this problem. Studies on molecular genetic profile of pancreatic cancer may represent an important approach. This study was focused on the mutations of p53 and DPC4 detectable in the bile of patients with histologically proven pancreatic cancers.

MATERIALS AND PATIENTS

We analysed specimens of bile collected through percutaneous transhepatic biliary catheters, placed to treat malignant biliary obstruction in 25 patients with pancreatic adenocarcinoma. A percentage of mutation was obtained of 43 % for the microsatellite D17S945 (p53), 54% and 50 % for D18S46 and D18S474 (DPC4), respectively. The percentage of amplification was 67%, 93,6%, and 80%.

CONCLUSION

We consider the results encouraging enough to decide to enlarge the number of patients examined. The aim is to determine if a test for DPC4 and p53 mutations is eligible for introduction in clinical routine use. More sets of samples are required to satisfactorily answer this question.

Molecular pathogenesis of pancreatic cancer

Pancreatic cancer is an almost universally fatal disease, with a five-year survival rate of 5%. Research into both sporadic and inherited forms of pancreatic cancer has yielded tremendous advances in the understanding of this disease at the molecular level. Elucidating genetic alterations in pancreatic cancer has identified various abnormalities ranging from gross chromosomal abnormalities to point mutations, many of which influence the development and progression of pancreatic cancer. Identifying precursor lesions within pancreatic ducts has led to the formulation of a progression model of pancreatic cancer and subsequent identification of early- and late-stage changes leading to invasive cancer. Ultimately, understanding the genetic events underlying the development of pancreatic cancer may serve as a useful adjunct in the screening and treatment of patients suffering from, or at risk for, pancreatic cancer.

Analysis of Ki-67 antigen expression, DNA proliferative fraction, and survival in resected cancer of the pancreas

BACKGROUND

Prognostic markers for pancreas cancer, such as CEA, CA19-9, ploidy analysis, and S-phase determination using flow cytometry, have not been consistently predictive. We chose to evaluate nuclear proliferation, as measured by the MIB-1 monoclonal antibody and digital image analysis, as a prognostic marker in pancreatic carcinoma, and compare the findings with DNA ploidy and S-phase analysis. MIB-1 identifies the Ki67 antigen present in nuclei of cells in all phases of the cell cycle except G0.

METHODS

We retrospectively reviewed 33 patients with pancreatic adenocarcinoma resected for cure between 1989 and 1994 with available fixed tissue. Sectioned tissue was stained with MIB-1, and the number of positively stained nuclei determined and expressed as a MIB-1 labeling index (LI) by quantitative image analysis. Disaggregated nuclei were analyzed by flow cytometry using standard techniques.

RESULTS

MIB-1 LI for pancreas cancers was heterogeneous within and between cancers. The MIB-1 LI for the cancers was 28 +/- 15 (median 29). There was no correlation between survival and MIB-1 expression (R(2) = 0.03). Likewise, there was no correlation between MIB-1 LI and percentage of cells in S-phase, G(2)/M, or total proliferating cells (S+G(2)/M; R(2) = 0.01), nor was there a difference between MIB-1 LI and ploidy (P = 0.88).

CONCLUSIONS

We conclude that in our patient population, nuclear proliferation in pancreatic cancer, as determined by expression of Ki67 nuclear antigen, does not appear to correlate with survival and is not a useful prognostic marker. Despite intuitive thoughts to the contrary, there is no correlation between cell cycle analysis as determined by flow cytometry and Ki67 expression in pancreas cancer. Current methods of assessing prognosis after curative resection of cancer of the pancreas, including lymph node and margin status, tumor size, and possibly DNA ploidy as determined by flow cytometry, are not augmented by the assessment of nuclear proliferation by image analysis using the MIB-1 monoclonal antibody.

Premalignant conditions of the pancreas

Premalignant conditions of the pancreas include benign tumours of the pancreas, intraepithelial neoplasia arising within pancreatic ducts, and tumours of the neuroendocrine cells of the pancreas. In addition, there is a variety of rare genetic conditions that predispose to pancreatic exocrine malignancies such as Peutz-Jeghers syndrome, hereditary non-polyposis colorectal cancer syndrome, familial pancreatitis, germline BRCA2 mutations, and pancreatic endocrine malignancies such as type 1 neurofibromatosis (von Recklinghausen's disease) and multiple endocrine neoplasia type 1. More controversial is the concept of chronic pancreatitis and diabetes mellitus as conditions that increase the risk of pancreatic cancer. However, there is no doubt that smoking is a potentiating factor for pancreatic cancer, especially in people who have familial/genetic risk factors. This review will include the recently proposed new nomenclature and classification system for intraepithelial neoplasia in the pancreatic ducts, an overview of the various familial syndromes that are associated with an increased risk of pancreatic tumours, the surveillance programmes that have been introduced to monitor such families, and methods for early diagnosis.

Quantity of mutant K-ras gene in pancreatic secretions for diagnosis of pancreatic carcinoma with different assays: analysis of 100 patients

BACKGROUND

Two types of quantitative assay kits for K-ras mutations, PCR-preferential homoduplex formation assay (PHFA) and enriched PCR and enzyme-linked mini-sequence assay (ELMA), were recently developed. The K-ras mutations were analyzed using these assays.

MATERIALS AND METHODS

DNA was extracted from the pancreatic juice which was obtained by endoscopy from 38 patients with pancreatic neoplasms (23 adenocarcinomas and 15 intraductal papillary neoplasms) and from 62 without it.

RESULTS

The results of the two methods were mutually correlative. K-ras mutation was detected at high levels (mutant ras genes occupied >2% of all K-ras genes) in 25 of the 38 cases (66%) with pancreatic neoplasm. It was also detected at high levels in 9 of the 14 cases (64%) with pancreatic cyst. In contrast, the mutant gene was detected at a lower level (<2%) in other cases.

CONCLUSIONS

Quantitative analysis of the mutant ras gene provided a useful tool for diagnosing the pancreatic carcinoma when the percentage of the mutant is high, especially when the types of mutation were either GAT or GTT.

Differential diagnosis between chronic pancreatitis and pancreatic cancer: value of the detection of KRAS2 mutations in circulating DNA

KRAS2 mutations in codon 12 have been detected in about 80% of pancreatic cancers. The aim of this study was to evaluate the value of KRAS2 mutations detection in circulating deoxyribo nucleic acid to differentiate pancreatic cancer from chronic pancreatitis. Circulating deoxyribonucleic acid was isolated from serum in 47 patients with histologically proven pancreatic adenocarcinomas (26 males, median age 65 years) and 31 controls with chronic pancreatitis (26 males, median age 48 years). Mutations at codon 12 of KRAS2 gene were searched for using polymerase chain reaction and allele specific amplification. Serum carbohydrate antigen 19.9 levels were also determined. KRAS2 mutations were found in 22 patients (47%) with pancreatic cancer and in four controls with chronic pancreatitis (13%) (P<0.002). None of the latter developed a pancreatic cancer within the 36 months of median follow-up. The sensitivity, specificity, positive and negative predictive values of serum serum KRAS2 mutations for the diagnosis of pancreatic cancer were 47, 87, 85 and 52%, respectively. KRAS2 mutations were not related to age, gender, smoking habit, tumour stage, or survival. Among the 26 patients with normal or non-contributive (due to cholestasis) serum carbohydrate antigen 19.9 levels, 14 (54%) had KRAS2 mutations. The combination of KRAS2 and carbohydrate antigen 19.9 gave a sensitivity, specificity, positive and negative predictive values for the diagnosis of pancreatic cancer of 98, 77, 87 and 96%, respectively. Detection of KRAS2 mutations in circulating deoxyribo nucleic acid has a low sensitivity but a specificity about 90% for the diagnosis of pancreatic cancer. It seems particularly useful when serum carbohydrate antigen 19.9 levels are normal or inconclusive. A combined normal serum carbohydrate antigen 19.9 and absence of circulating KRAS2 mutations makes the diagnosis of pancreatic cancer extremely unlikely.

Molecular diagnosis of early pancreatic ductal adenocarcinoma in high-risk patients

The prevalence of pancreatic cancer in the general population is too low--even in high-prevalence areas such as Northern Europe and North America (8-12 per 10(5) population)--relative to the diagnostic accuracy of present detection methods to permit primary screening in the asymptomatic adult population. The recognition that the lifetime risk of developing pancreatic cancer for patients with hereditary pancreatitis (HP) is extremely high (20% by the age of 60 years and 40% by the age of 70 years) poses considerable challenges and opportunities for secondary screening in those patients without any clinical features of pancreatic cancer. Even for secondary screening, the detection of cancer at a biological stage that would be amenable to cure by surgery (total pancreatectomy) still requires diagnostic modalities with a very high sensitivity and specificity. Conventional radiological imaging methods such as endoluminal ultrasound and endoscopic retrograde pancreatography, which have proved to be valuable in the early detection of early neoplastic lesions in patients with familial pancreatic cancer, may well be applicable to patients with HP but only in those without gross morphological features of chronic pancreatitis (other than parenchymal atrophy). Unfortunately, most cases of HP also have associated gross features of chronic pancreatitis that are likely to seriously undermine the diagnostic value of these conventional imaging modalities. Pre-malignant molecular changes can be detected in the pancreatic juice of patients. Thus, the application of molecular screening in patients with HP is potentially the most powerful method of detection of early pancreatic cancer. Although mutant (mt) K-ras can be detected in the pancreatic juice of most patients with pancreatic cancer, it is also present in patients with non-inherited chronic pancreatitis who do not progress to pancreatic cancer (at least in the short to medium term), as well as increasingly in the older population without pancreatic disease. Nevertheless, the presence of mt-K-ras may identify a genuinely higher-risk group, enabling additional diagnostic imaging and molecular resources to be focussed on such a group. What is clear is that prospective multi-centre studies, such as that being pursued by the European Registry of Hereditary Pancreatitis and Familial Pancreatic Cancer (EUROPAC), are essential for the development of an effective secondary screening programme for these patients.

Cyclooxygenase 2 expression in pancreatic adenocarcinoma and pancreatic intraepithelial neoplasia: an immunohistochemical analysis with automated cellular imaging

We immunohistochemically examined material from 36 pancreata (adenocarcinomas, 30 lesions; pancreatic intraepithelial neoplasia [PanIN], 65; normal pancreatic ducts, 30) for cyclooxygenase 2 (COX-2) with an automated platform. We analyzed 7 to 10 discrete foci and generated an average percentage of positive cells and average staining intensity for each lesion. These 2 values were then multiplied to create an overall "HistoScore" for each lesion. COX-2 demonstrated considerable heterogeneity of expression between and within cases. The overall average percentage of positive cells in adenocarcinomas was 47.3%; in PanINs, 36.3%; and in normal ducts, 19.2%. COX-2 was expressed in more than 20% of cells in 23 adenocarcinomas (77%), 42 PanINs (65%), and 12 normal ducts (40%). The overall average HistoScore for adenocarcinomas was 6.1; for PanINs, 5.4; and for normal ducts, 3.5. Significant differences in COX-2 expression were demonstrable in adenocarcinomas vs normal ducts, PanINs vs normal ducts, and PanIN 2/3 vs PanIN 1a/1b. In general, the pattern of COX-2 expression increased from normal to PanIN to adenocarcinoma. The up-regulation of COX-2 in a subset of noninvasive precursor lesions makes it a potential target for chemoprevention with selective COX-2 inhibitors.

K-ras, p53, and DPC4 (MAD4) alterations in fine-needle aspirates of the pancreas: a molecular panel correlates with and supplements cytologic diagnosis

Between January 1997 and February 2000, 101 fine-needle pancreatic aspirates were obtained. After a cytologic diagnosis was made, possible molecular alterations were determined on the 94 aspirates with adequate tissue using a molecular panel (K-ras, p53, and DPC4 [MAD4] genes). The 94 aspirates were categorized as follows: diagnostic of adenocarcinoma, 48 (51%); atypical (suggestive of but not diagnostic of adenocarcinoma), 19 (20%); negative for adenocarcinoma, 25 (2 7%); diagnostic of a neoplasm other than adenocarcinoma, 2 (2%). Clinical follow-up revealed that 3 patients (12%) with negative cytologic diagnoses and 12 patients (63%) with atypical cytologic diagnoses had adenocarcinoma. Of 63 with a final diagnosis of adenocarcinoma, 42 (67%) had an alteration in at least 1 of the genes analyzed. In contrast, only 2 (6%) of 31 patients without adenocarcinoma had an alteration in 1 gene on the panel. Overall, the molecular analyses supported the diagnosis of adenocarcinoma in 6 (32%) of 19 aspirates originally diagnosed as atypical by cytology alone. A molecular panel that includes the K-ras, p53, and DPC4 (MAD4) genes correlates with and can supplement traditional cytologic diagnosis of pancreatic fine-needle aspirates.

Gene mutation as a target for early detection in cancer diagnosis

The increasing number of genetic aberrations implicated in the development of human cancer has prompted a search to detect them at the earliest possible stage of their formation. Of the many such genetic changes identified thus far, relatively few meet the standard for markers in early diagnosis and prognosis, namely that the genetic modifications occur during the early onset phase of cancer development. Parallel to the increasing number of such genes is the growing availability of technologies using more powerful and cost-efficient methods that enable mass screening for genetic alterations. The purpose of this review is to summarize the currently available genes that can serve as markers for early detection of cancers and methods that allow their detection.

The molecular genetics of pancreatic ductal carcinoma: a review

In the last several years, numerous advances in the field of molecular genetics have been applied to pancreatic ductal carcinoma- the 5th leading cause of cancer death in the United States. This review summaries the current knowledge about adenocarcinoma of the pancreas.

Topographic analysis of K- ras mutations in histologically normal lung tissues and tumours of lung cancer patients

Mutations in the K- ras gene are very common in lung tumours and are implicated in the development of lung cancer, but the timing of their occurrence remains poorly understood. We investigated K- ras mutations in cell samples microdissected by laser capture microscopy at multiple sites from lung tissue sections representing tumour tissue and matched histologically normal tissue obtained from 48 lung cancer patients. K- ras mutations were detected in cell samples from 10 of 38 (26.3%) lung adenocarcinomas and in none of the histologically normal or tumour cell samples taken from 10 lung squamous cell carcinomas. Of the K- ras mutation-positive adenocarcinomas, in 4 cases a mutation was found in only the tumour tissue, in 1 case a mutation was found only in the histologically normal tissue, and in 5 cases mutations were found in both the tumour tissue and histologically normal tissue. Among these 5 cases, 2 had identical mutations in both the tumour tissue and histologically normal tissue, 2 had 1 mutation in the tumour tissue and 2 mutations in the histologically normal tissue, 1 of which was identical to the mutation found in the tumour, and 1 case had 2 codon 12 mutations in tumour tissue and 2 mutations, in codons 9 and 11, in histologically normal tissue. These results showed that K- ras mutations are frequent in histologically normal cells taken from outside lung adenocarcinomas and suggest that some of these mutations may represent early events which could pave the way of lung carcinogenesis.

Update on familial pancreatic cancer

Approximately 5% to 10% of patients with pancreatic cancer have one or more first-degree relatives with this disease. A subset of these individuals have a hereditary form of pancreatic cancer designated by association with such hereditary disorders as familial adenomatous polyposis, hereditary nonpolyposis colorectal cancer, hereditary pancreatitis, or familial atypical multiple mole melanoma (FAMMM) syndrome. A subset of those FAMMM kindred with the CDKN2A (p16) germline mutation that expresses both pancreatic cancer and malignant melanoma may constitute a new hereditary pancreatic cancer-prone syndrome.

Hereditary Chronic Pancreatitis: Implications for Surgical Treatment and Follow-Up

Hereditary pancreatitis is an uncommon cause of chronic pancreatitis in Western society. It should be suspected when chronic pancreatitis presents in young adults. The diagnosis is made when chronic pancreatitis is present in several members of the same family who are determined not to have other risk factors for chronic pancreatitis. Molecular research focusing on mutations in the tripsinogen gene has uncovered the genetic defects associated with hereditary pancreatitis, and this knowledge has suggested the possible pathophysiologic mechanism of this disease. Because patients with hereditary pancreatitis develop their disease early in life they are very likely to require treatment for complications. As in patients with chronic pancreatitis of other etiologies those with hereditary pancreatitis should be treated medically for acute exacerbations. When complications occur or when the disease causes intractable pain surgery is recommended. Surgical therapy is tailored to the patient's pancreatic anatomy based on endoscopic retrograde cholangiopancreatography or CT scan. The two patients described in this report underwent successful longitudinal pancreaticojejunostomy (Puestow procedure) with good results. Finally it has been shown that patients with hereditary pancreatitis are at increased risk for developing pancreatic adenocarcinoma. Although not widely used pancreatic cancer screening programs have been suggested for surveillance of these patients.

ME-PCR for the identification of mutated K-ras in serum and bile of pancreatic cancer patients: an unsatisfactory technique for clinical applications

Our aim was to assess the clinical reliability of mutated K-ras detection in serum or bile for the diagnosis of pancreatic cancer using ME-PCR. DNA was extracted from 1 ml serum obtained from 29 patients with pancreatic cancer and 12 control subjects. ME-PCR was optimized using a mixture of normal DNA added with different amounts of mutated DNA. The analysis of sera obtained from the 29 patients and of bile obtained from 11 pancreatic cancer patients demonstrated the presence of mutated K-ras in two (6.9%) and four cases (36%). By contrast K-ras was not amplifiable in any of the 12 serum samples obtained from healthy controls. In conclusion the DNA obtained from pancreatic cancer patients' sera is suitable for K-ras amplification and for the identification of codon 12 point mutations. However ME-PCR alone has an unsatisfactory sensitivity for the detection of pancreatic cancer using serum DNA as starting template.

Dpc4 protein in mucinous cystic neoplasms of the pancreas: frequent loss of expression in invasive carcinomas suggests a role in genetic progression

DPC4 (MADH4, SMAD4) is a nuclear transcription factor shown to be genetically inactivated in over half of infiltrating ductal adenocarcinomas of the pancreas. Immunohistochemical labeling for the DPC4 gene product using a monoclonal antibody has recently been shown to be an extremely sensitive and specific marker for DPC4 gene alterations in pancreatic adenocarcinomas. Mucinous cystic neoplasms (MCNs) are a biologically less aggressive subtype of pancreatic neoplasm that may show benign, borderline, or overtly malignant features. However, the role of DPC4 inactivation in the development of MCNs has not been examined. The immunohistochemical expression of Dpc4 protein was therefore examined in 36 mucinous cystic neoplasms using this previously characterized monoclonal antibody. The 36 mucinous cystic neoplasms studied included 23 adenomas, 1 tumor with borderline potential, 5 tumors with carcinoma in situ, and 7 invasive carcinomas. Twenty-nine (100%) of the 29 noninvasive mucinous cystic neoplasms strongly expressed Dpc4 in the neoplastic epithelium. In striking contrast, only one (14%) of seven infiltrating carcinomas expressed Dpc4 in the neoplastic epithelium (p = 0.0001). The adjacent stroma retained expression of this protein in all 36 cases. In invasive MCNs with loss of Dpc4 expression, areas of carcinoma in situ were identified in the same paraffin sections, and these areas of carcinoma in situ retained expression of Dpc4. The frequent loss of Dpc4 expression in invasive MCNs indicates that genetic inactivation of Dpc4 occurs late in the neoplastic progression of these tumors and suggests a relationship to the development of invasion.