Molecular detection of pancreatic neoplasia: Current status and future promise

Towards an updated view on the clinical management of pancreatic adenocarcinoma: Current and future perspectives

Pancreatic cancer has a dire prognosis and will represent the second leading cause of cancer death in the next 10 years. The multifactorial approach represents one of the main issues in controlling the extension of this neoplasm. In recent years, the characteristics of the tumor microenvironment, metastasis mechanisms and the relationship between immune system and neoplastic cells have been described, which has made it possible to understand the pathophysiology of pancreatic adenocarcinoma. Currently, there is a failure to provide an effective preventive method or early detection, so patients present with an advanced stage at the time of diagnosis. Despite numerous efforts, little progress has been made in clinical outcome and in improving survival in long term. Therefore, in the recent years, diverse diagnostic tests, treatments and possible approaches have been developed in the fields of radiotherapy, chemotherapy and surgery to find a combination of them that improves life expectancy in patients diagnosed with pancreatic cancer. At the moment, numerous clinical trials are being conducted to evaluate preventive diagnostic procedures such as serological markers or perfecting available imaging tests. On the other hand, implementation of immunotherapy is being studied in a neoplasm that has lagged in the application of this procedure since present possible treatments do not substantially improve quality of life. Therefore, the purpose of our study is to summarize the main progresses that have been made in the diagnosis, treatment and screening of this disease, explaining the limitations that have been observed and analyzing future prospects in the management of this illness.

Similarities and Differences of Blood N-Glycoproteins in Five Solid Carcinomas at Localized Clinical Stage Analyzed by SWATH-MS

Cancer is mostly incurable when diagnosed at a metastatic stage, making its early detection via blood proteins of immense clinical interest. Proteomic changes in tumor tissue may lead to changes detectable in the protein composition of circulating blood plasma. Using a proteomic workflow combining N-glycosite enrichment and SWATH mass spectrometry, we generate a data resource of 284 blood samples derived from patients with different types of localized-stage carcinomas and from matched controls. We observe whether the changes in the patient's plasma are specific to a particular carcinoma or represent a generic signature of proteins modified uniformly in a common, systemic response to many cancers. A quantitative comparison of the resulting N-glycosite profiles discovers that proteins related to blood platelets are common to several cancers (e.g., THBS1), whereas others are highly cancer-type specific. Available proteomics data, including a SWATH library to study N-glycoproteins, will facilitate follow-up biomarker research into early cancer detection.

Incremental value of DNA analysis in pancreatic cysts stratified by clinical risk factors

BACKGROUND AND AIMS

We determined the incremental predictive value of pancreatic cyst fluid molecular analysis to assessing malignancy risk over long-term follow-up of a well-characterized cohort, given the underlying predictive value of imaging parameters routinely used to triage such patients.

METHODS

Patients who lacked initial cytologic malignancy in cyst fluid and had final pathology or a follow-up period of more than 2 years were included. Patient outcomes determined the malignancy-free survival of patients with high-risk stigmata (HRS), worrisome features (WFs), and DNA abnormalities. DNA analysis included 3 abnormalities: loss of heterozygosity mutations among a panel of tumor suppressor genes, Kras mutation, and elevated DNA quantity.

RESULTS

Included were 478 patients; 209 had surgical pathology-derived outcomes and 269 had clinical follow-up of >2 years. Eleven percent had malignant outcome. Forty-two patients had HRS, 272 lacked both HRS and WFs, and 164 lacked HRS but had WFs. DNA abnormalities did not statistically change long-term malignancy risk in patients with HRS or in patients lacking both HRS and WFs. Among patients with WFs, the presence of ≥2 DNA abnormalities significantly increased malignancy risk (relative risk, 5.2; P = .002) and the absence of all DNA abnormalities significantly decreased risk (relative risk, .4; P = .040). Sensitivity analysis confirmed results of survival analysis over differing baseline malignancy probabilities.

CONCLUSIONS

Our study defines the clinical characteristic of patients in which DNA abnormality testing has the greatest impact on patient outcomes. Use of DNA abnormality testing is supported in a carefully selected patient population limited to cysts with WFs.

LOX and ACSL5 as potential relapse markers for pancreatic cancer patients

Pancreatic cancer is one of the most malignant diseases and has a poor prognosis. The screening and validation of biomarkers with predictive value for prognosis and treatment efficacy are important. To identify potential prognostic markers of pancreatic cancer patients, we conducted a study that included 99 pancreatic cancer patients. Three patients with PFS>18 months were enrolled in the treat group, and three patients with PFS<12 months were enrolled in the control group. Differentially expressed genes (DEGs) between these two groups were analyzed by whole-genome expression microarray. A total of 178 DEGs were identified, including 110 up-regulated and 68 down-regulated genes. Next, 24 candidate genes were selected for validation by qPCR based on fold change and previous studies. The results showed that the mRNA levels of four candidate genes, including ACSL5, SLC44A4, LOX, and TOX3, were correlated with PFS. Immunohistochemical staining was performed to validate the protein expression levels of these four markers. The results showed that patients with LOX ^high, ACSL5 ^low and TOX3 ^low expression had a significantly shorter PFS than those with LOX ^low, ACSL5 ^high and TOX3 ^high expression. Multivariable analysis revealed differentiation, tumor stage, LOX expression, and ACSL5 expression were independent prognostic factors for PFS. Then, we use the TCGA database to explore the underlying mechanism of LOX influence pancreatic cancer progression. Protein-protein interaction network of ACSL5 was established by STRING to uncover the potential regulation mechanism. Our findings reveal that LOX and ACSL5 are potential prognostic markers for the prognosis of pancreatic cancer patients.

Pancreatic cancer associated with obesity and diabetes: an alternative approach for its targeting

BACKGROUND

Pancreatic cancer (PC) is among foremost causes of cancer related deaths worldwide due to generic symptoms, lack of effective screening strategies and resistance to chemo- and radiotherapies. The risk factors associated with PC include several metabolic disorders such as obesity, insulin resistance and type 2 diabetes mellitus (T2DM). Studies have shown that obesity and T2DM are associated with PC pathogenesis; however, their role in PC initiation and development remains obscure.

MAIN BODY

Several biochemical and physiological factors associated with obesity and/or T2DM including adipokines, inflammatory mediators, and altered microbiome are involved in PC progression and metastasis albeit by different molecular mechanisms. Deep understanding of these factors and causal relationship between factors and altered signaling pathways will facilitate deconvolution of disease complexity as well as lead to development of novel therapies. In the present review, we focuses on the interplay between adipocytokines, gut microbiota, adrenomedullin, hyaluronan, vanin and matrix metalloproteinase affected by metabolic alteration and pancreatic tumor progression.

CONCLUSIONS

Metabolic diseases, such as obesity and T2DM, contribute PC development through altered metabolic pathways. Delineating key players in oncogenic development in pancreas due to metabolic disorder could be a beneficial strategy to combat cancers associated with metabolic diseases in particular, PC.

Highly Discriminant Methylated DNA Markers for the Non-endoscopic Detection of Barrett's Esophagus

BACKGROUND

Minimally invasive methods have been described to detect Barrett's esophagus (BE), but are limited by subjectivity and suboptimal accuracy. We identified methylated DNA markers (MDMs) for BE in tissue and assessed their accuracy on whole esophagus brushings and capsule sponge samples.

METHODS

Step 1: Unbiased whole methylome sequencing was performed on DNA from BE and normal squamous esophagus (SE) tissue. Discriminant MDM candidates were validated on an independent patient cohort (62 BE cases, 30 controls) by quantitative methylation specific PCR (qMSP). Step 2: Selected MDMs were further evaluated on whole esophageal brushings (49 BE cases, 36 controls). 35 previously sequenced esophageal adenocarcinoma (EAC) MDMs were also evaluated. Step 3: 20 BE cases and 20 controls were randomized to swallow capsules sponges (25 mm, 10 pores or 20 pores per inch (ppi)) followed endoscopy. DNA yield, tolerability, and mucosal injury were compared. Best MDM assays were performed on this cohort.

RESULTS

Step 1: 19 MDMs with areas under the ROC curve (AUCs) >0.85 were carried forward. Step 2: On whole esophageal brushings, 80% of individual MDM candidates showed high accuracy for BE (AUCs 0.84-0.94). Step 3: The capsule sponge was swallowed and withdrawn in 98% of subjects. Tolerability was superior with the 10 ppi sponge with minimal mucosal injury and abundant DNA yield. A 2-marker panel (VAV3 + ZNF682) yielded excellent BE discrimination (AUC = 1).

CONCLUSIONS

Identified MDMs discriminate BE with high accuracy. BE detection appears safe and feasible with a capsule sponge. Corroboration in larger studies is warranted. ClinicalTrials.gov number NCT02560623.

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.

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.

Overexpression of Topoisomerase 2-Alpha Confers a Poor Prognosis in Pancreatic Adenocarcinoma Identified by Co-Expression Analysis

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is the fourth most common cause of human cancer-related death in the developed countries. Its progression and prognosis are influenced by a complex network of gene interactions.

AIMS

The purpose of this study is to explore key genes associated with pancreatic ductal adenocarcinoma and to predict the possible mechanisms.

METHODS

A weighted gene co-expression network was constructed to identify gene modules associated with the progression of PDAC.

RESULTS

In the significant module (R ² = 0.30), a total of 20 network hub genes were identified, 6 of which were also hub nodes in the protein-protein interaction network of the module genes. In validation, TOP2A has a higher correlation than other hub genes. Also, in the test set (n = 118), TOP2A was more highly expressed in PDAC than normal pancreas samples (P < 0.001). What is more, gene set enrichment analysis demonstrated that eight gene sets (n = 118), "nucleotide excision repair," "P53 signaling pathway," "proteasome," "mismatch repair," "homologous recombination," "DNA replication," "cell cycle," and "base excision repair," were enriched (FDR < 0.05). In gene ontology analysis, TOP2A in the enriched set was associated with cell cycle and cell division. Furthermore, survival analysis indicated that higher expression of TOP2A resulted in the lower overall survival time as well as disease-free survival time.

CONCLUSION

TOP2A was identified in association with the progression and prognosis of PDAC probably by regulating cell cycle and p53 signaling pathway.

Metabolomic biomarkers of pancreatic cancer: a meta-analysis study

Pancreatic cancer (PC) is an aggressive disease with high mortality rates, however, there is no blood test for early detection and diagnosis of this disease. Several research groups have reported on metabolomics based clinical investigations to identify biomarkers of PC, however there is a lack of a centralized metabolite biomarker repository that can be used for meta-analysis and biomarker validation. Furthermore, since the incidence of PC is associated with metabolic syndrome and Type 2 diabetes mellitus (T2DM), there is a need to uncouple these common metabolic dysregulations that may otherwise diminish the clinical utility of metabolomic biosignatures. Here, we attempted to externally replicate proposed metabolite biomarkers of PC reported by several other groups in an independent group of PC subjects. Our study design included a T2DM cohort that was used as a non-cancer control and a separate cohort diagnosed with colorectal cancer (CRC), as a cancer disease control to eliminate possible generic biomarkers of cancer. We used targeted mass spectrometry for quantitation of literature-curated metabolite markers and identified a biomarker panel that discriminates between normal controls (NC) and PC patients with high accuracy. Further evaluation of our model with CRC, however, showed a drop in specificity for the PC biomarker panel. Taken together, our study underscores the need for a more robust study design for cancer biomarker studies so as to maximize the translational value and clinical implementation.

Islet inflammation and ductal proliferation may be linked to increased pancreatitis risk in type 2 diabetes

Pancreatitis is more frequent in type 2 diabetes mellitus (T2DM), although the underlying cause is unknown. We tested the hypothesis that ongoing β cell stress and apoptosis in T2DM induces ductal tree proliferation, particularly the pancreatic duct gland (PDG) compartment, and thus potentially obstructs exocrine outflow, a well-established cause of pancreatitis. PDG replication was increased 2-fold in human pancreas from individuals with T2DM, and was associated with increased pancreatic intraepithelial neoplasia (PanIN), lesions associated with pancreatic inflammation and with the potential to obstruct pancreatic outflow. Increased PDG replication in the prediabetic human-IAPP-transgenic (HIP) rat model of T2DM was concordant with increased β cell stress but preceded metabolic derangement. Moreover, the most abundantly expressed chemokines released by the islets in response to β cell stress in T2DM, CXCL1, -4, and -10, induced proliferation in human pancreatic ductal epithelium. Also, the diabetes medications reported as potential modifiers for the risk of pancreatitis in T2DM modulated PDG proliferation accordingly. We conclude that chronic stimulation and proliferation of the PDG compartment in response to islet inflammation in T2DM is a potentially novel mechanism that serves as a link to the increased risk for pancreatitis in T2DM and may potentially be modified by currently available diabetes therapy.

Murine and human pancreatic tumor exosome recovery in mouse serum: Diagnostic and prognostic potential and target cell delivery

Exosomes (Exo), powerful intercellular communicators, are recovered in all body fluids, suggesting suitability for diagnosis and prognosis. Easy in vitro manipulation recommends Exo as drug vehicles. Aiming to consolidate diagnostic and therapeutic potential of Exo, we evaluated recovery and fate of tumor (TEX) and exogenous Exo in syngeneic and xenogeneic mice bearing a murine or a human pancreatic adenocarcinoma. A significant increase in serum (S)-TEX was observed 2 weeks after tumor cell application. Instead, S-TEX declined within 3-6 days after tumor excision. Intravenously injected dye-labeled TEX were rapidly cleared from the serum. Partly being degraded in the liver, the majority is taken-up by PBL, liver, bone marrow and lung cells. In the tumor-bearing host TEX persisted longer becoming enriched in tumor cells and metastatic organs. Accordingly, an antibody blockade of a TEX marker hampered disseminated tumor cell settlement in selected organs. In brief, a tumor marker panel appears suited for S-TEX recovery. In murine models, S-TEX are qualified for therapy control and follow-up studies. Despite rapid clearance from the serum, Exo uptake by host cells is most promising for tailored Exo as drug transporter.

Athymic nude mice as an experimental model for cancer treatment

Athymic nude mice, a murine strain bearing spontaneous deletion in the Foxn1 gene that causes deteriorated or absent thymus (which results in inhibited immune system with reduction of number of T cells), represent a widely used model in cancer research having long lasting history as a tool for preclinical testing of drugs. The review describes three models of athymic mice that utilize cancer cell lines to induce tumors. In addition, various methods that can be applied in order to evaluate activity of anticancer agents in these models are shown and discussed. Although each model has certain disadvantages, they are still considered as inevitable instruments in many fields of cancer research, particularly in finding new drugs that would more effectively combat the cancer disease or enhance the use of current chemotherapy. Finally, the review summarizes strengths and weaknesses as well as future perspectives of the athymic nude mice model in cancer research.

Inhibition of ATR potentiates the cytotoxic effect of gemcitabine on pancreatic cancer cells through enhancement of DNA damage and abrogation of ribonucleotide reductase induction by gemcitabine

Pancreatic cancer is a highly malignant disease with a dismal prognosis. Gemcitabine (GEM)-based chemotherapy is the first-line treatment for patients with advanced disease, although its efficacy is very limited, mainly due to drug resistance. Ataxia telangiectasia and Rad3-related (ATR) plays a critical role in the DNA damage response (DDR) which has been implicated in GEM resistance. Thus, targeting ATR represents a promising approach to enhance GEM antitumor activity. In the present study, we tested the antitumor activity of AZ20, a novel ATR-selective inhibitor, alone or combined with GEM in 5 pancreatic cancer cell lines. AZ20 treatment of the pancreatic cancer cell lines resulted in growth inhibition, with IC50 values ranging from 0.84 to 2.4 µM, but limited cell death. As expected, treatment of pancreatic cancer cell lines with AZ20 caused decreased phosphorylation of CHK1 (S-345). However, this was accompanied by DNA damage and S and G2/M cell cycle arrest, independent of TP53 gene mutational status. Importantly, combination of AZ20 with GEM resulted in synergistic inhibition of cell growth and cooperative induction of cell death in the pancreatic cancer cell lines. AZ20 significantly increased GEM-induced DNA damage and almost completely abrogated GEM-induced expression of the M2 subunit of ribonucleotide reductase. These findings suggest that inhibition of ATR is a promising strategy to enhance the antitumor activity of GEM for treating pancreatic cancer.

Identification of candidate miRNA biomarkers for pancreatic ductal adenocarcinoma by weighted gene co-expression network analysis

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with a dismal prognosis which is, among others, due to a lack of suitable biomarkers and therapeutic targets. Previously, basic gene expression analysis methods have been used for their identification, but recently new algorithms have been developed allowing more comprehensive data analyses. Among them, weighted gene co-expression network analysis (WGCNA) has already been applied to several cancer types with promising results.

METHODS

We applied WGCNA to miRNA expression data from PDAC patients. Specifically, we processed microarray-based expression data of 2555 miRNAs in serum from 100 PDAC patients and 150 healthy subjects. We identified network modules of co-expressed miRNAs in the healthy subject dataset and verified their preservation in the PDAC dataset. In the non-preserved modules, we selected key miRNAs and carried out functional enrichment analyses of their experimentally known target genes. Finally, we tested their prognostic significance using overall survival analyses.

RESULTS

Through WGCNA we identified several miRNAs that discriminate healthy subjects from PDAC patients and that, therefore, may play critical roles in PDAC development. At a functional level, we found that they regulate p53, FoxO and ErbB associated cellular signalling pathways, as well as cell cycle progression and various genes known to be involved in PDAC development. Some miRNAs were also found to serve as novel prognostic biomarkers, whereas others have previously already been proposed as such, thereby validating the WGCNA approach. In addition, we found that these novel data may explain at least some of our previous PDAC gene expression analysis results.

CONCLUSIONS

We identified several miRNAs critical for PDAC development using WGCNA. These miRNAs may serve as biomarkers for PDAC diagnosis/prognosis and patient stratification, and as putative novel therapeutic targets.

APC promoter is frequently methylated in pancreatic juice of patients with pancreatic carcinomas or periampullary tumors

Early detection of pancreatic and periampullary neoplasms is critical to improve their clinical outcome. The present authors previously demonstrated that DNA hypermethylation of adenomatous polyposis coli (APC), histamine receptor H2 (HRH2), cadherin 13 (CDH13), secreted protein acidic and cysteine rich (SPARC) and engrailed-1 (EN-1) promoters is frequently detected in pancreatic tumor cells. The aim of the present study was to assess their prevalence in pancreatic juice of carcinomas of the pancreas and periampullary area. A total of 135 pancreatic juices obtained from 85 pancreatic cancer (PC), 26 ampullary carcinoma (AC), 10 intraductal papillary mucinous neoplasm (IPMN) and 14 chronic pancreatitis (CP) patients were analyzed. The methylation status of the APC, HRH2, CDH13, SPARC and EN-1 promoters was analyzed using methylation specific-melting curve analysis (MS-MCA). Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations were also tested with allele-specific quantitative polymerase chain reaction amplification. Out of the 5 promoters analyzed, APC (71%) and HRH2 (65%) were the most frequently methylated in PC juice. APC methylation was also detected at a high frequency in AC (76%) and IPMN (80%), but only occasionally observed in CP (7%). APC methylation had a high sensitivity (71-80%) for all types of cancer analyzed. The panel (where a sample scored as positive when ≥2 markers were methylated) did not outperform APC as a single marker. Finally, KRAS detection in pancreatic juice offered a lower sensitivity (50%) and specificity (71%) for detection of any cancer. APC hypermethylation in pancreatic juice, as assessed by MS-MCA, is a frequent event of potential clinical usefulness in the diagnosis of pancreatic and periampullary neoplasms.

Progress and potential of exosome analysis for early pancreatic cancer detection

INTRODUCTION

Pancreatic cancer (PaCa) is the most deadly malignancy, due to late diagnosis prohibiting surgery. Thus, strong efforts are taken improving early diagnosis via biomarkers recovered in the serum of PaCa patients.

AREAS COVERED

One promising option are PaCa-derived exosomes in patients' sera. Exosomes, small vesicles delivered by live cells and recovered in all body fluids, are a powerful diagnostic tool due to relative stability and composition covering the whole range of cancer-related biomarkers including proteins, metabolites, DNA, DNA modifications, coding and noncoding RNA. We discuss the mechanisms accounting for the condensed packaging of biomarkers, refer to studies using PaCa serum-exosomes for diagnosis. Based on an extensive literature search, we outline questions that answers may help establishing a serum-exosome-based screening for early PaCa detection. Expert commentary: Improved proteomic and genomic characterization and progress in the biogenesis of exosomes will allow for optimized and unified screening panels for PaCa diagnosis via TEX in body fluids.

Weighted gene co-expression network analysis reveals key genes involved in pancreatic ductal adenocarcinoma development

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy. Up till now, the patient's prognosis remains poor which, among others, is due to the paucity of reliable early diagnostic biomarkers. In the past, candidate diagnostic biomarkers and therapeutic targets have been delineated from genes that were found to be differentially expressed in normal versus tumour samples. Recently, new systems biology approaches have been developed to analyse gene expression data, which may yield new biomarkers. As of yet, the weighted gene co-expression network analysis (WGCNA) tool has not been applied to PDAC microarray-based gene expression data.

METHODS

PDAC microarray-based gene expression datasets, listed in the Gene Expression Omnibus (GEO) database, were analysed. After pre-processing of the data, we built two final datasets, Normal and PDAC, encompassing 104 and 129 patient samples, respectively. Next, we constructed a weighted gene co-expression network and identified modules of co-expressed genes distinguishing normal from disease conditions. Functional annotations of the genes in these modules were carried out to highlight PDAC-associated molecular pathways and common regulatory mechanisms. Finally, overall survival analyses were carried out to assess the suitability of the genes identified as prognostic biomarkers.

RESULTS

Using WGCNA, we identified several key genes that may play important roles in PDAC. These genes are mainly related to either endoplasmic reticulum, mitochondrion or membrane functions, exhibit transferase or hydrolase activities and are involved in biological processes such as lipid metabolism or transmembrane transport. As a validation of the applied method, we found that some of the identified key genes (CEACAM1, MCU, VDAC1, CYCS, C15ORF52, TMEM51, LARP1 and ERLIN2) have previously been reported by others as potential PDAC biomarkers. Using overall survival analyses, we found that several of the newly identified genes may serve as biomarkers to stratify PDAC patients into low- and high-risk groups.

CONCLUSIONS

Using this new systems biology approach, we identified several genes that appear to be critical to PDAC development. As such, they may represent potential diagnostic biomarkers as well as therapeutic targets with clinical utility.

Is metastatic pancreatic cancer an untargetable malignancy?

Metastatic pancreatic cancer (MPC) is one of the most aggressive malignancies, known to be chemo-resistant and have been recently considered resistant to some targeted therapies (TT). Erlotinib combined to gemcitabine is the only targeted therapy that showed an overall survival benefit in MPC. New targets and therapeutic approaches, based on new-TT, are actually being evaluated in MPC going from immunotherapy, epigenetics, tumor suppressor gene and oncogenes to stromal matrix regulators. We aim in this paper to present the major causes rendering MPC an untargetable malignancy and to focus on the new therapeutic modalities based on TT in MPC.