Quantitative analysis of NPTX2 hypermethylation is a promising molecular diagnostic marker for pancreatic cancer

Diagnosing and monitoring pancreatic cancer through cell-free DNA methylation: progress and prospects

Pancreatic cancer is one of the most challenging cancers due to its high mortality rates. Considering the late diagnosis and the limited survival benefit with current treatment options, it becomes imperative to optimize early detection, prognosis and prediction of treatment response. To address these challenges, significant research efforts have been undertaken in recent years to develop liquid-biopsy-based biomarkers for pancreatic cancer. In particular, an increasing number of studies point to cell-free DNA (cfDNA) methylation analysis as a promising non-invasive approach for the discovery and validation of epigenetic biomarkers with diagnostic or prognostic potential. In this review we provide an update on recent advancements in the field of cfDNA methylation analysis in pancreatic cancer. We discuss the relevance of DNA methylation in the context of pancreatic cancer, recent cfDNA methylation research, its clinical utility, and future directions for integrating cfDNA methylation analysis into routine clinical practice.

Circulating NPTX2 methylation as a non-invasive biomarker for prognosis and monitoring of metastatic pancreatic cancer

BACKGROUND

Pancreatic cancer is the most lethal cancer with a dismal prognosis mainly due to diagnosis at advanced stage and ineffective treatments. CA19-9 levels and computed tomography (CT) imaging are the main standard criteria for evaluating disease progression and treatment response. In this study we explored liquid biopsy-based epigenetic biomarkers for prognosis and monitoring disease in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC).

METHODS

Plasma samples were collected from 44 mPDAC patients at the time of diagnosis, and in 15 of them, additional samples were obtained during follow-up of the disease. After cell-free DNA (cfDNA), isolation circulating levels of methylated NPTX2, SPARC, BMP3, SFRP1 and TFPI2 genes were measured using digital droplet PCR (ddPCR). BEAMing technique was performed for quantitation of RAS mutations in cfDNA, and CA19-9 was measured using standard techniques.

RESULTS

NPTX2 was the most highly and frequently methylated gene in cfDNA samples from mPDAC patients. Higher circulating NPTX2 methylation levels at diagnosis were associated with poor prognosis and efficiently stratified patients for prediction of overall survival (6.06% cut-off, p = 0.0067). Dynamics of circulating NPTX2 methylation levels correlated with disease progression and response to therapy and predicted better than CA19-9 the evolution of disease in mPDAC patients. Remarkably, in many cases the disease progression detected by CT scan was anticipated by an increase in circulating NPTX2 methylation levels.

CONCLUSIONS

Our study supports circulating NPTX2 methylation levels as a promising liquid biopsy-based clinical tool for non-invasive prognosis, monitoring disease evolution and response to treatment in mPDAC patients.

Systematic review and meta-analysis: Diagnostic performance of DNA alterations in pancreatic juice for the detection of pancreatic cancer

BACKGROUND AND AIMS

Pancreatic cancer has a dismal prognosis. So far, imaging has been proven incapable of establishing an early enough diagnosis. Thus, biomarkers are urgently needed for early detection and improved survival. Our aim was to evaluate the pooled diagnostic performance of DNA alterations in pancreatic juice.

METHODS

A systematic literature search was performed in EMBASE, MEDLINE Ovid, Cochrane CENTRAL and Web of Science for studies concerning the diagnostic performance of DNA alterations in pancreatic juice to differentiate patients with high-grade dysplasia or pancreatic cancer from controls. Study quality was assessed using QUADAS-2. The pooled prevalence, sensitivity, specificity and diagnostic odds ratio were calculated.

RESULTS

Studies mostly concerned cell-free DNA mutations (32 studies: 939 cases, 1678 controls) and methylation patterns (14 studies: 579 cases, 467 controls). KRAS, TP53, CDKN2A, GNAS and SMAD4 mutations were evaluated most. Of these, TP53 had the highest diagnostic performance with a pooled sensitivity of 42% (95% CI: 31-54%), specificity of 98% (95%-CI: 92%-100%) and diagnostic odds ratio of 36 (95% CI: 9-133). Of DNA methylation patterns, hypermethylation of CDKN2A, NPTX2 and ppENK were studied most. Hypermethylation of NPTX2 performed best with a sensitivity of 39-70% and specificity of 94-100% for distinguishing pancreatic cancer from controls.

CONCLUSIONS

This meta-analysis shows that, in pancreatic juice, the presence of distinct DNA mutations (TP53, SMAD4 or CDKN2A) and NPTX2 hypermethylation have a high specificity (close to 100%) for the presence of high-grade dysplasia or pancreatic cancer. However, the sensitivity of these DNA alterations is poor to moderate, yet may increase if they are combined in a panel.

Promoter Hypomethylation of TGFBR3 as a Risk Factor of Alzheimer’s Disease: An Integrated Epigenomic-Transcriptomic Analysis

Alzheimer’s disease (AD) is characterized by the abnormal deposition of amyloid-β (Aβ) plaques and tau tangles in the brain and accompanied with cognitive impairment. However, the fundamental cause of this disease remains elusive. To elucidate the molecular processes related to AD, we carried out an integrated analysis utilizing gene expression microarrays (GSE36980 and GSE5281) and DNA methylation microarray (GSE66351) in temporal cortex of AD patients from the Gene Expression Omnibus (GEO) database. We totally discovered 409 aberrantly methylated and differentially expressed genes. These dysregulated genes were significantly enriched in biological processes including cell part morphogenesis, chemical synaptic transmission and regulation of Aβ formation. Through convergent functional genomic (CFG) analysis, expression cross-validation and clinicopathological correlation analysis, higher TGFBR3 level was observed in AD and positively correlated with Aβ accumulation. Meanwhile, the promoter methylation level of TGFBR3 was reduced in AD and negatively associated with Aβ level and advanced Braak stage. Mechanically, TGFBR3 might promote Aβ production by enhancing β- and γ-secretase activities. Further investigation revealed that TGFBR3 may exert its functions via Synaptic vesicle cycle, Calcium signaling pathway and MAPK signal pathway by regulating hub genes GNB1, GNG3, CDC5L, DYNC1H1 and FBXW7. Overall, our findings highlighted TGFBR3 as an AD risk gene and might be used as a diagnostic biomarker and therapeutic target for AD treatment.

Diagnostic value of neuronal pentraxin II methylation in patients with pancreatic cancer: Meta-analysis

BACKGROUND

Pancreatic cancer (PC) is a devasting disease of which mortality almost parallels its incidence. PC tissue may express aberrantly methylated neuronal pentraxin II (NPTX2), but it is unclear what the consequences of this are.

METHODS

We systematically searched PubMed, Web of Science, the Chinese National Knowledge Infrastructure (CNKI), from inception to July 15, 2020, to identify if the detection of methylated NPTX2 have sufficient sensitivity and specificity to identify PC from other benign pancreatic diseases.

RESULTS

Majority of the studies obtained samples from pancreatic juice by endoscopy or surgery and composed of population with chronic pancreatitis, benign cystic lesion, intraductal papillary mucinous neoplasm, and healthy controls. Our results demonstrated that the diagnostic value of methylated NPTX2 is of widely various sensitivity and specificity and it shown higher specificity in differentiate PC from benign diseases. The lab method of quantitative real-time methylation-specific PCR (QMSP) has higher specificity than real-time methylation-specific PCR (MSP) in detecting the indicator.

CONCLUSIONS

NPTX2 methylation could serve as a promising molecular biomarker for pancreatic cancer diagnosis, for its high diagnostic value in differentiating pancreatic cancer from benign pancreatic disease with the lab method. The variable sensitivity of methylated NPTX2 was multifactorial, and it must be promoted before applied as screening test in clinical practice. Furthermore, experiments on methylated NPTX2 were needed to expanded for lower the heterogeneity.

A Comparison of Short- and Long-Term Soy Protein Isolate Intake and Its Ability to Reduce Liver Steatosis in Obese Zucker Rats Through Modifications of Genes Involved in Inflammation and Lipid Transport

Obesity can lead to several health disorders including nonalcoholic fatty liver disease (NAFLD), the aggregation of lipids within hepatocytes, and consequent inflammation of the liver tissue. Previously, we reported that feeding obese Zucker rats with soy protein isolate (SPI) can reduce liver steatosis. To understand how SPI reduced liver steatosis, we conducted global gene expression analysis on liver samples obtained from these rats after short- (8 weeks) and long-term SPI feeding (16 weeks). We compared and contrasted these data using Ingenuity Pathway Analysis (IPA) software. This study focused mainly on target molecules that could be participating in inflammation processes and lipid metabolism that are well-known components of NAFLD. Inflammatory response was predicted to be inhibited in animals fed the SPI diet at both 8 and 16 weeks of experiment. This general prediction was based on negative activation z scores obtained through IPA (z score < -2.0, P < .00001) for eight aspects of immune function/inflammatory response. Lipid metabolism was predicted to be strongly enhanced in rats fed the SPI diet for 16 weeks than for 8 weeks. This prediction was based on positive activation z scores (z scores >2.0, P < .00001) of eight functions involved in lipid transport and metabolism. We observed that the longer the rats were fed the SPI diet, the more beneficial it resulted against NAFLD. Based on our findings, the predicted reductions in inflammatory mechanisms while enhancing lipid transport out of the liver could be the reasons behind the reduction of liver steatosis.

Comparison of liver gene expression by RNAseq and PCR analysis after 8 weeks of feeding soy protein isolate- or casein-based diets in an obese liver steatosis rat model

Differential expression of genes provides insight into fundamental mechanisms associated with the ability of soy protein isolate to attenuate liver steatosis in genetically obese rats.

Cell-free DNA promoter hypermethylation in plasma as a predictive marker for survival of patients with pancreatic adenocarcinoma

Introduction

Few prognostic biomarkers are available for pancreatic cancer. The aim of this study is to examine the correlation between the survival of pancreatic adenocarcinoma patients and hypermethylated genes in plasma-derived cell-free DNA.

Methods

Consecutive patients with pancreatic adenocarcinoma were prospectively included and staged according to the TNM classification. Methylation-specific PCR of 28 genes was conducted. A survival prediction model independent of cancer stage and stage-specific survival prediction models were developed by multivariable Cox regression analysis using backward stepwise selection.

Results

Ninety-five patients with pancreatic adenocarcinoma were included. Patients with more than 10 hypermethylated genes had a HR of 2.03 (95% CI; 1.15-3.57) compared to patients with fewer hypermethylated genes. Three survival prediction models were developed: Total group; (American Society of Anesthesiologists score (ASA)=3, GSTP1, SFRP2, BNC1, SFRP1, TFPI2, and WNT5A) Risk groups 2, 3 and 4 had a HR of 2.65 (95% CI; 1.24-5.66), 4.34 (95% CI; 1.98-9.51) and 21.19 (95% CI; 8.61-52.15), respectively, compared to risk group 1. Stage I-II; (ASA=3, SFRP2, and MESTv2) Risk groups 2, 3 and 4 had a HR of 4.83 (95% CI; 2.01-11.57), 9.12 (95% CI; 2.18-38.25) and 70.90 (95% CI; 12.63-397.96), respectively, compared to risk group 1. Stage IV; (BMP3, NPTX2, SFRP1, and MGMT) Risk group 2 had a HR of 5.23 (95% CI; 2.13-12.82) compared to risk group 1.

Conclusion

Prediction models based on cell-free DNA hypermethylation stratified pancreatic adenocarcinoma patients into risk groups according to survival. The models have the potential to work as prognostic biomarkers. However, further validation of the results is required to substantiate the findings.

Measuring Animal Age with DNA Methylation: From Humans to Wild Animals

DNA methylation (DNAm) is a key mechanism for regulating gene expression in animals and levels are known to change with age. Recent studies have used DNAm changes as a biomarker to estimate chronological age in humans and these techniques are now also being applied to domestic and wild animals. Animal age is widely used to track ongoing changes in ecosystems, however chronological age information is often unavailable for wild animals. An ability to estimate age would lead to improved monitoring of (i) population trends and status and (ii) demographic properties such as age structure and reproductive performance. Recent studies have revealed new examples of DNAm age association in several new species increasing the potential for developing DNAm age biomarkers for a broad range of wild animals. Emerging technologies for measuring DNAm will also enhance our ability to study age-related DNAm changes and to develop new molecular age biomarkers.

The integration of epigenetics and genetics in nutrition research for CVD risk factors

There is increasing evidence documenting gene-by-environment (G × E) interactions for CVD related traits. However, the underlying mechanisms are still unclear. DNA methylation may represent one of such potential mechanisms. The objective of this review paper is to summarise the current evidence supporting the interplay among DNA methylation, genetic variants, and environmental factors, specifically (1) the association between SNP and DNA methylation; (2) the role that DNA methylation plays in G × E interactions. The current evidence supports the notion that genotype-dependent methylation may account, in part, for the mechanisms underlying observed G × E interactions in loci such asAPOE, IL6and ATP-binding cassette A1. However, these findings should be validated using intervention studies with high level of scientific evidence. The ultimate goal is to apply the knowledge and the technology generated by this research towards genetically based strategies for the development of personalised nutrition and medicine.

NPTX2 is associated with neoadjuvant therapy response in rectal cancer

BACKGROUND

Neoadjuvant chemoradiation (CRT) is recommended for locally advanced rectal cancer. Tumor response varies from pathologic complete response (pCR) to no tumor regression. The mechanisms behind CRT resistance remain undefined. In our previously generated complementary DNA microarrays of pretreatment biopsies from rectal cancer patients, neuronal pentraxin 2 (NPTX2) expression discriminated patients with pCR from those with residual tumor. As tumor response is prognostic for survival, we sought to evaluate the clinical relevance of NPTX2 in rectal cancer.

MATERIALS AND METHODS

Real-time quantitative polymerase chain reaction was used to evaluate NPTX2 messenger RNA expression in individual rectal cancers before CRT. Tumors with NPTX2 expression <50% of normal rectum were defined as NPTX2-low and those with >50% were defined as NPTX2-high. NPTX2 levels were compared to response to therapy and oncologic outcomes using Mann-Whitney, Kruskal-Wallis, chi-square, and Mantel-Cox (log-rank) tests, as appropriate.

RESULTS

Rectal cancers from 40 patients were included. The mean patient age was 56.8 years, and 30% were female. pCR was achieved in eight of 40 patients (20%). In these patients, messenger RNA NPTX2 levels were significantly decreased compared to those with residual cancer (fold change 30.4, P = 0.017). Patients with NPTX2-low tumors (n = 13) achieved improved response to treatment (P = 0.012 versus NPXT2-high tumors), with 38.5% and 46.1% of patients achieving complete or moderate response, respectively. Of patients with NPTX2-high tumors (n = 27), 11.1% and 18.5% achieved complete or moderate response, respectively. No recurrence or death was recorded in patients with NPTX2-low tumors, reflecting more favorable disease-free survival (P = 0.045).

CONCLUSIONS

Decreased NPTX2 expression in rectal adenocarcinomas is associated with improved response to CRT and improved prognosis. Further studies to validate these results and elucidate the biological role of NPTX2 in rectal cancer are needed.

NPTX1 is a novel epigenetic regulation gene and associated with prognosis in lung cancer

BACKGROUND

CpG island hypermethylation of gene promoters is a well-known mechanism of epigenetic regulation of tumor related-genes and is directly linked to lung carcinogenesis. Alterations in the pattern of methylation of the NPTX1 gene have not yet been studied in detail in human lung cancer.

METHODS

Methylation-specific PCR (MSP) and bisulfite sequencing PCR (BSP) were used to analyze promoter methylation status, and real-time quantitative reverse transcription-PCR (qRT-PCR) examined mRNA levels. Subsequently, we compared the methylation profile of NPTX1 in samples of neoplastic and non-neoplastic lung tissue taken from the same patients by using quantitative methylation specific PCR (QMSP).

RESULTS

CpG island hypermethylation in promoter of NPTX1 was confirmed in lung cancer cell lines. A significant increase in NPTX1 methylation was identified in lung cancer specimens compared to adjacent noncancerous tissues and that it was negatively correlated with its mRNA expression. The overall survival time among patients carrying methylated NPTX1 tumors was significantly shorter as compared to those with unmethylated NPTX1 tumors (P = 0.011). Moreover, methylation of NPTX1 gene was found to be an independent prognostic factor for poor overall survival based on multivariate analysis models (p = 0.021), as was age ≥60 years old (p = 0.012) and TNM stage (p < 0.001).

CONCLUSIONS

These results suggest that NPTX1 hypermethylation and consequent mRNA changes might be an important molecular mechanism in lung cancer. Epigenetic alterations in NPTX1 may serve as potential diagnostic and prognostic biomarkers in lung cancer.

Epigenetics and pancreatic cancer: Pathophysiology and novel treatment aspects

An improvement in pancreatic cancer treatment represents an urgent medical goal. Late diagnosis and high intrinsic resistance to conventional chemotherapy has led to a dismal overall prognosis that has remained unchanged during the past decades. Increasing knowledge about the molecular pathogenesis of the disease has shown that genetic alterations, such as mutations of K-ras, and especially epigenetic dysregulation of tumor-associated genes, such as silencing of the tumor suppressor p16^ink4a, are hallmarks of pancreatic cancer. Here, we describe genes that are commonly affected by epigenetic dysregulation in pancreatic cancer via DNA methylation, histone acetylation or miRNA (microRNA) expression, and review the implications on pancreatic cancer biology such as epithelial-mesenchymal transition, morphological pattern formation, or cancer stem cell regulation during carcinogenesis from PanIN (pancreatic intraepithelial lesions) to invasive cancer and resistance development. Epigenetic drugs, such as DNA methyltransferases or histone deactylase inhibitors, have shown promising preclinical results in pancreatic cancer and are currently in early phases of clinical development. Combinations of epigenetic drugs with established cytotoxic drugs or targeted therapies are promising approaches to improve the poor response and survival rate of pancreatic cancer patients.

NPTX2 hypermethylation in pure pancreatic juice predicts pancreatic neoplasms

The neuronal pentraxin II (NPTX2) gene is methylated in over 90% primary pancreatic cancer tissues but rarely in normal pancreatic ductal epithelia. Here, the authors investigated the utility of methylated NPTX2 as a diagnostic marker for pancreatic cancer in pure pancreatic juice samples of patients with benign and malignant pancreatic diseases, including pancreatic cancer, intraductal papillary mucinous neoplasm or chronic pancreatitis using methylation-specific polymerase chain reaction (MSP) and quantitative MSP. MSP assays revealed that the incidence of aberrant NPTX methylation in pure pancreatic juice samples was 64.5% (20 of 31) in patients with pancreatic cancer, 70.0% (7 of 10) in patients with malignant intraductal papillary mucinous neoplasm, 33.3% (2 of 6) in patients with benign intraductal papillary mucinous neoplasm and 21.7% (5 of 23) in patients with chronic pancreatitis. NPTX2 hypermethylation in patients with chronic pancreatitis was significantly lower than that of pancreatic cancer (P < 0.01) or patients with intraductal papillary mucinous neoplasm (P < 0.05). At a cutoff value of 1.39 for quantitative MSP, the incidence of aberrant NPTX2 methylation was 61.3% (19 of 31) in patients with pancreatic cancer, 50.0% (5 of 10) in patients with malignant intraductal papillary mucinous neoplasm, 0% in patients with benign intraductal papillary mucinous neoplasm and 8.7% (2 of 23) in patients with chronic pancreatitis. There was a significant difference in NPTX2 methylation between pancreatic cancer and chronic pancreatitis (P < 0.01). Our findings indicate that detection of aberrant methylation of NPTX2 in pure pancreatic juice samples could be useful as a molecular marker to discriminate between patients with malignant and benign disease of the pancreas.

The role of DNA methylation in aging, rejuvenation, and age-related disease

DNA methylation is a major control program that modulates gene expression in a plethora of organisms. Gene silencing through methylation occurs through the activity of DNA methyltransferases, enzymes that transfer a methyl group from S-adenosyl-L-methionine to the carbon 5 position of cytosine. DNA methylation patterns are established by the de novo DNA methyltransferases (DNMTs) DNMT3A and DNMT3B and are subsequently maintained by DNMT1. Aging and age-related diseases include defined changes in 5-methylcytosine content and are generally characterized by genome-wide hypomethylation and promoter-specific hypermethylation. These changes in the epigenetic landscape represent potential disease biomarkers and are thought to contribute to age-related pathologies, such as cancer, osteoarthritis, and neurodegeneration. Some diseases, such as a hereditary form of sensory neuropathy accompanied by dementia, are directly caused by methylomic changes. Epigenetic modifications, however, are reversible and are therefore a prime target for therapeutic intervention. Numerous drugs that specifically target DNMTs are being tested in ongoing clinical trials for a variety of cancers, and data from finished trials demonstrate that some, such as 5-azacytidine, may even be superior to standard care. DNMTs, demethylases, and associated partners are dynamically shaping the methylome and demonstrate great promise with regard to rejuvenation.

Epigenetic regulation and role of metastasis suppressor genes in pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is distinguished by rapid dissemination. Thus, genetic and/or epigenetic deregulation of metastasis suppressor genes (MSG) is a likely event during early pancreatic carcinogenesis and a potential diagnostic marker for the disease. We investigated 9 known MSGs for their role in the dissemination of PDAC and examined their promoters for methylation and its use in PDAC detection.

METHODS

MRNA expression of 9 MSGs was determined in 18 PDAC cell lines by quantitative RT-PCR and promoter methylation was analyzed by Methylation Specific PCR and validated by Bisulfite Sequencing PCR. These data were compared to the cell lines' in vivo metastatic and invasive potential that had been previously established. Statistical analysis was performed with SPSS 20 using 2-tailed Spearman's correlation with P < 0.05 being considered significant.

RESULTS

Complete downregulation of MSG-mRNA expression in PDAC cell lines vs. normal pancreatic RNA occurred in only 1 of 9 investigated genes. 3 MSGs (CDH1, TIMP3 and KiSS-1) were significantly methylated. Methylation only correlated to loss of mRNA expression in CDH1 (P < 0.05). Bisulfite Sequencing PCR showed distinct methylation patterns, termed constant and variable methylation, which could distinguish methylation-regulated from non methylation-regulated genes. Higher MSG mRNA-expression did not correlate to less aggressive PDAC-phenotypes (P > 0.14).

CONCLUSIONS

Genes with metastasis suppressing functions in other tumor entities did not show evidence of assuming the same role in PDAC. Inactivation of MSGs by promoter methylation was an infrequent event and unsuitable as a diagnostic marker of PDAC. A distinct methylation pattern was identified, that resulted in reduced mRNA expression in all cases. Thus, constant methylation patterns could predict regulatory significance of a promoter's methylation prior to expression analysis and hence present an additional tool during target gene selection.

The role of quantitative NPTX2 hypermethylation as a novel serum diagnostic marker in pancreatic cancer

OBJECTIVES

The majority of pancreatic cancers are found to be unresectable, and the only chance for cure lies on early detection and complete resection. Several genes have been discovered to be aberrantly methylated in primary pancreatic cancer tissue, and this cancer DNA can be detected in the plasma. The aims of this study were to develop a novel diagnostic marker based on epigenetic characteristics of pancreatic cancer.

METHODS

We enrolled 104 patients with pancreatic cancer, 60 with chronic pancreatitis, and 5 with benign biliary stone diseases. The blood samples were collected before surgery or any kinds of treatment modalities. DNA was extracted from the plasma of each patient, and NPTX2 (neuronal pentraxin II) CpG island hypermethylation was examined quantitatively by real-time polymerase chain reaction.

RESULTS

NPTX2 hypermethylation levels were significantly higher compared with chronic pancreatitis (P = 0.016). The sensitivity and specificity were 80% and 76%, respectively (cutoff = 0.015). NPTX2 gene hypermethylation level was significantly elevated in correlation with higher American Joint Committee on Cancer stages.

CONCLUSIONS

The aberrantly methylated NPTX2 gene may help to distinguish between chronic pancreatitis and pancreatic cancer with conventional diagnostic tools and could become a valuable diagnostic marker.

Advances in biomarker research for pancreatic cancer

Pancreatic cancer (PC) is a leading cause of cancer related deaths in United States. The lack of early symptoms results in latestage detection and a high mortality rate. Currently, the only potentially curative approach for PC is surgical resection, which is often unsuccessful because the invasive and metastatic nature of the tumor masses makes their complete removal difficult. Consequently, patients suffer relapses from remaining cancer stem cells or drug resistance that eventually lead to death. To improve the survival rate, the early detection of PC is critical. Current biomarker research in PC indicates that a serum carbohydrate antigen, CA 19-9, is the only available biomarker with approximately 90% specificity to PC. However, the efficacy of CA 19-9 for assessing prognosis and monitoring patients with PC remains contentious. Thus, advances in technology and the detection of new biomarkers with high specificity to PC are needed to reduce the mortality rate of pancreatic cancer.

Epigenetic predictor of age

From the moment of conception, we begin to age. A decay of cellular structures, gene regulation, and DNA sequence ages cells and organisms. DNA methylation patterns change with increasing age and contribute to age related disease. Here we identify 88 sites in or near 80 genes for which the degree of cytosine methylation is significantly correlated with age in saliva of 34 male identical twin pairs between 21 and 55 years of age. Furthermore, we validated sites in the promoters of three genes and replicated our results in a general population sample of 31 males and 29 females between 18 and 70 years of age. The methylation of three sites—in the promoters of the EDARADD, TOM1L1, and NPTX2 genes—is linear with age over a range of five decades. Using just two cytosines from these loci, we built a regression model that explained 73% of the variance in age, and is able to predict the age of an individual with an average accuracy of 5.2 years. In forensic science, such a model could estimate the age of a person, based on a biological sample alone. Furthermore, a measurement of relevant sites in the genome could be a tool in routine medical screening to predict the risk of age-related diseases and to tailor interventions based on the epigenetic bio-age instead of the chronological age.

The neuronal pentraxin II gene (NPTX2) inhibit proliferation and invasion of pancreatic cancer cells in vitro

The neuronal pentraxin II gene (NPTX2) is expressed in numerous tissues, such as the pancreas and the liver. While its activity in the brain is known to be regulated by neuronal activity, its function in the pancreas is unclear. In this study, we investigated the impact of NPTX2 on the proliferation, migration, invasion, apoptosis, and cell cycle of the pancreatic cancer cells. The expression levels of NPTX2 and their relation to the methylation level of the NPTX2 gene promoter in five pancreatic cancer cell lines were observed. The lower expression of NPTX2 in the cells was restored after the treatment of DNA methyltransferase inhibitor (5-aza-2'-deoxycytidine). Additionally, a full-length NPTX2 cDNA was transfected into pancreatic cancer cells (PANC-1) and we obtained the stably transfected cells (PANC-1-NPTX2). The ectopic NPTX2 expression significantly promoted G0-G1 arrest and cell apoptosis, and reduced cell proliferation, migration and invasion. Notably, the pro-apoptotic gene bax expression was significantly up-regulated while pro-survival gene bcl-2 did not significantly change in the stably transfected cells. Meanwhile, Cyclin D1 was significantly down-regulated. This study suggests that NPTX2, as a tumor-suppressor, plays an anti-tumor effect on pancreatic cancer and its low expression, due to promoter hypermethylation, may play a role in the tumorigenesis of pancreatic cancer.

Differential diagnosis of pancreatic tumors by molecular analysis of clinical specimens

OBJECTIVE

To describe the capabilities and limitations of the current state of the art in pancreatic cancer diagnostics and to discuss recent progress in the development of novel, highly accurate molecular diagnostic approaches.

RESULTS

Molecular analyses currently under evaluation as novel diagnostic tests include detection of point mutations, genomic imbalances, aberrant methylation patterns and gene expression changes on the mRNA and protein levels in pancreatic juice, fine needle aspiration biopsies and brush cytologies.

CONCLUSIONS

In exploratory studies, several candidate molecular markers show great potential to serve as general indicators of malignancy, but need to be validated in large, controlled, prospective studies. Multiplexing of diagnostic tests, e.g. in the form of specialized DNA microarrays, may provide more differentiated diagnoses such as the distinction of various tumor types or prognostic information for individual patients. The MolDiag-Paca consortium is strongly engaged in advancing these developments on a European level.