The good, the bad and the ugly: a tale of miR-101, miR-21 and miR-155 in pancreatic intraductal papillary mucinous neoplasms

Implication of epigenetics in pancreas development and disease

Pancreas development is controlled by a complex interaction of signaling pathways and transcription factor networks that determine pancreatic specification and differentiation of exocrine and endocrine cells. Epigenetics adds a new layer of gene regulation. DNA methylation, histone modifications and non-coding RNAs recently appeared as important epigenetic factors regulating pancreas development. In this review, we report recent findings obtained by analyses in model organisms as well as genome-wide approaches that demonstrate the role of these epigenetic regulators in the control of exocrine and endocrine cell differentiation, identity, function, proliferation and regeneration. We also highlight how altered epigenetic processes contribute to pancreatic disorders: diabetes and pancreatic cancer. Uncovering these epigenetic events can help to better understand these diseases, provide novel therapeutical targets for their treatment, and improve cell-based therapies for diabetes.

Contribution of microRNA analysis to characterisation of pancreatic lesions: a review

Pancreatic tumours are usually very aggressive cancer with a poor prognosis. A limitation of pancreatic imaging techniques is that lesions are often of ambiguous relevance. The inability to achieve a definitive diagnosis based on cytological evaluation of specimens, due to sampling error, paucicellular samples or coexisting inflammation, might lead to delay in clinical management. Given the morbidity associated with pancreatectomy, a proper selection of patients for surgery is fundamental. Many studies have been conducted in order to identify specific markers that could support the early diagnosis of pancreatic lesions, but, to date, none of them allow to diagnose pancreatic cancer with high sensitivity and specificity. MicroRNAs (miRNA) are small non-coding RNAs (19-25 nucleotides) that regulate gene expression interacting with mRNA targets. It is now established that each tissue shows a characteristic miRNA expression pattern that could be modified in association with a number of different diseases including neoplasia. Due to their key role in the regulation of gene expression, in the last years several studies have investigated miRNA tissue-specific expression, quantification and functional analysis to understand their peculiar involvement in cellular processes. The aim of this review is to focus on miRNA expression in pancreatic cancer and their putative role in early characterisation of pancreatic lesions.

Pancreatic adenocarcinoma pathology: changing "landscape"

Pancreatic cancer is a devastating disease. At time of diagnosis the disease is usually advanced and only a minority of patients are eligible for surgical resection. The overall 5-year survival is 6%. However, survival of patients with early stage pancreatic cancer is significantly better. To improve the prognosis of patients with pancreatic cancer, it is essential to diagnose and treat pancreatic cancer in the earliest stage. Prevention of pancreatic cancer by treating noninvasive precursor lesions just before they invade tissues can potentially lead to even better outcomes. Pancreatic carcinogenesis results from a stepwise progression in which accumulating genetic alterations drive neoplastic progression in well-defined precursor lesions, ultimately giving rise to an invasive adenocarcinoma. A thorough understanding of the genetic changes that drive pancreatic carcinogenesis can lead to identification of biomarkers for early detection and targets for therapy. Recent next-generation sequencing (NGS) studies have shed new light on our understanding of the natural history of pancreatic cancer and the precursor lesions that give rise to these cancers. Importantly, there is a significant window of opportunity for early detection and treatment between the first genetic alteration in a cell in the pancreas and development of full-blown pancreatic cancer. The current views on the pathology and genetics of pancreatic carcinogenesis that evolved from studies of pancreatic cancer and its precursor lesions are discussed in this review.

microRNAs with prognostic significance in pancreatic ductal adenocarcinoma: A meta-analysis

BACKGROUND

Reports have described the prognostic relevance of microRNAs (miRNAs) in patients treated for pancreatic ductal adenocarcinoma (PDAC). However, many of these include small numbers of patients. To increase statistical power and improve translation, we performed a systematic review and meta-analysis to determine a pooled conclusion. We examined the impact of miRNAs on overall survival (OS) and disease-free survival (DFS) in PDAC.

METHODS

Eligible studies were identified and quality assessed using multiple search strategies (last search December 2014). Data were collected from studies correlating clinical outcomes with dysregulated tumoural or blood miRNAs. Studies were pooled, and combined hazard ratios (HRs) with 95% confidence intervals (CIs) were used to estimate strength of the associations.

RESULTS

Twenty studies involving 1525 patients treated for PDAC were included. After correcting for publication bias, OS was significantly shortened in patients with high tumoural miR-21 (adjusted HR = 2.48; 1.96-3.14). This result persisted when only studies adjusting for adjuvant chemotherapy were combined (adjusted HR = 2.72; 1.91-3.89). High miR-21 also predicted reduced DFS (adjusted HR = 3.08; 1.78-5.33). Similarly, we found significant adjusted HRs for poor OS for high miR-155, high miR-203, and low miR-34a; and unadjusted HRs for high miR-222 and high miR-10b. The small number of studies, limited number of miRNAs and paucity of multivariate analyses are the limitations of our study.

CONCLUSIONS

This is the first rigorous pooled analysis assessing miRNAs as prognostic biomarkers in PDAC. Tumoural miR-21 overexpression emerged as an important predictor of poor prognosis after PDAC resection independent of other clinicopathologic factors, including adjuvant chemotherapy use.

Key nodes of a microRNA network associated with the integrated mesenchymal subtype of high-grade serous ovarian cancer

Metastasis is the main cause of cancer mortality. One of the initiating events of cancer metastasis of epithelial tumors is epithelial-to-mesenchymal transition (EMT), during which cells dedifferentiate from a relatively rigid cell structure/morphology to a flexible and changeable structure/morphology often associated with mesenchymal cells. The presence of EMT in human epithelial tumors is reflected by the increased expression of genes and levels of proteins that are preferentially present in mesenchymal cells. The combined presence of these genes forms the basis of mesenchymal gene signatures, which are the foundation for classifying a mesenchymal subtype of tumors. Indeed, tumor classification schemes that use clustering analysis of large genomic characterizations, like The Cancer Genome Atlas (TCGA), have defined mesenchymal subtype in a number of cancer types, such as high-grade serous ovarian cancer and glioblastoma. However, recent analyses have shown that gene expression-based classifications of mesenchymal subtypes often do not associate with poor survival. This “paradox” can be ameliorated using integrated analysis that combines multiple data types. We recently found that integrating mRNA and microRNA (miRNA) data revealed an integrated mesenchymal subtype that is consistently associated with poor survival in multiple cohorts of patients with serous ovarian cancer. This network consists of 8 major miRNAs and 214 mRNAs. Among the 8 miRNAs, 4 are known to be regulators of EMT. This review provides a summary of these 8 miRNAs, which were associated with the integrated mesenchymal subtype of serous ovarian cancer.

The genetic classification of pancreatic neoplasia

Cancer is caused by the accumulation of inherited and/or acquired alterations in specific genes. The recent decline in the cost of DNA sequencing has allowed tumor sequencing to be conducted on a large scale, which, in turn, has led to an unprecedented understanding of the genetic events that drive neoplasia. This understanding, when integrated with meticulous histologic analyses and with clinical findings, has direct clinical implications. The recent sequencing of all of the major types of cystic and noncystic neoplasms of the pancreas has revealed opportunities for molecular diagnoses and for personalized treatment. This review summarizes the results from these recent studies focusing on the clinical relevance of genomic data.

A genome-wide investigation of microRNA expression identifies biologically-meaningful microRNAs that distinguish between high-risk and low-risk intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMNs) are pancreatic ductal adenocarcinoma (PDAC) precursors. Differentiating between high-risk IPMNs that warrant surgical resection and low-risk IPMNs that can be monitored is a significant clinical problem, and we sought to discover a panel of mi(cro)RNAs that accurately classify IPMN risk status.

METHODOLOGY/PRINCIPAL FINDINGS

In a discovery phase, genome-wide miRNA expression profiling was performed on 28 surgically-resected, pathologically-confirmed IPMNs (19 high-risk, 9 low-risk) using Taqman MicroRNA Arrays. A validation phase was performed in 21 independent IPMNs (13 high-risk, 8 low-risk). We also explored associations between miRNA expression level and various clinical and pathological factors and examined genes and pathways regulated by the identified miRNAs by integrating data from bioinformatic analyses and microarray analysis of miRNA gene targets. Six miRNAs (miR-100, miR-99b, miR-99a, miR-342-3p, miR-126, miR-130a) were down-regulated in high-risk versus low-risk IPMNs and distinguished between groups (P<10-3, area underneath the curve (AUC) = 87%). The same trend was observed in the validation phase (AUC = 74%). Low miR-99b expression was associated with main pancreatic duct involvement (P = 0.021), and serum albumin levels were positively correlated with miR-99a (r = 0.52, P = 0.004) and miR-100 expression (r = 0.49, P = 0.008). Literature, validated miRNA:target gene interactions, and pathway enrichment analysis supported the candidate miRNAs as tumor suppressors and regulators of PDAC development. Microarray analysis revealed that oncogenic targets of miR-130a (ATG2B, MEOX2), miR-342-3p (DNMT1), and miR-126 (IRS-1) were up-regulated in high- versus low-risk IPMNs (P<0.10).

CONCLUSIONS

This pilot study highlights miRNAs that may aid in preoperative risk stratification of IPMNs and provides novel insights into miRNA-mediated progression to pancreatic malignancy. The miRNAs identified here and in other recent investigations warrant evaluation in biofluids in a well-powered prospective cohort of individuals newly-diagnosed with IPMNs and other pancreatic cysts and those at increased genetic risk for these lesions.

Diagnostic value of plasma miR-210 combined with serum tumor markers in pancreatic cancer

AIM: To evaluate the diagnostic value of the combination of plasma miR-210 with serum tumor markers in patients with pancreatic cancer.

METHODS: Sixty patients with pancreatic cancer, twenty patients with chronic pancreatitis, and ten normal people were included in the study. Total RNA was extracted from plasma samples for measurement of miR-210 levels using real-time PCR. Simultaneously, serum tumor markers carbohydrate antigen 199 (CA199), CA242 and carcino-embryonic antigen (CEA) were determined. The relationship between miR-210 levels and clinical characteristics of pancreatic cancer patients was analyzed. The diagnostic efficiency of combination of plasma miR-210 with serum tumor markers CA199, CA242, and CEA in pancreatic cancer patients was evaluated.

RESULTS: The relative abundance of plasma miR-210 was significantly higher in the pancreatic cancer group than in the chronic pancreatitis and normal groups (4.12 ± 4.51 vs 1.49 ± 3.94, -1.73 ± 4.82; P < 0.01 for both). Plasma miR-210 levels showed no significant correlation with CA199, CA242, CEA, tumor diameter, TNM stage or clinical stage in pancreatic cancer patients. Analysis using a binary logistic regression model showed that the diagnostic sensitivity and specificity of miR-210 alone were 96.7% and 50% for the pancreatic cancer group vs normal group, 95% and 25% for the pancreatic cancer group vs chronic pancreatitis group, and 86.7% and 40% for the pancreatic cancer group vs chronic pancreatitis and normal group. When plasma miR-210 was combined with serum tumor markers CA199, CA242, or CEA, the sensitivity and specificity in the three groups were 96.7% and 70%, 90% and 85%, 86.7% and 90%, respectively.

CONCLUSION: The combination of plasma miR-210 with serum tumor markers CA199, CA242 or CEA can improve diagnostic efficiency in patients with pancreatic cancer.

AKT1 and SELP polymorphisms predict the risk of developing cachexia in pancreatic cancer patients

Pancreatic ductal adenocarcinoma (PDAC) patients have the highest risk of developing cachexia, which is a direct cause of reduced quality of life and shorter survival. Novel biomarkers to identify patients at risk of cachexia are needed and might have a substantial impact on clinical management. Here we investigated the prognostic value and association of SELP-rs6136, IL6-rs1800796 and AKT1-rs1130233 polymorphisms with cachexia in PDAC. Genotyping was performed in DNA from blood samples of a test and validation cohorts of 151 and 152 chemo-naive locally-advanced/metastatic PDAC patients, respectively. The association of SELP-rs6136, IL6-rs1800796 and AKT1-rs1130233 polymorphisms with cachexia as well as the correlation between cachexia and the candidate polymorphisms and overall survival were analyzed. Akt expression and phosphorylation in muscle biopsies were evaluated by specific ELISA assays. SELP-rs6136-AA and AKT1-rs1130233-AA/GA genotypes were associated with increased risk of developing cachexia in both cohorts (SELP: p = 0.011 and p = 0.045; AKT1: p = 0.004 and p = 0.019 for the first and second cohorts, respectively), while patients carrying AKT1-rs1130233-GG survived significantly longer (p = 0.002 and p = 0.004 for the first and second cohorts, respectively). In the multivariate analysis AKT1-rs1130233-AA/GA genotypes were significant predictors for shorter survival, with an increased risk of death of 1.7 (p = 0.002) and 1.6 (p = 0.004), in the first and second cohorts, respectively. This might be explained by the reduced phosphorylation of Akt1 in muscle biopsies from patients harboring AKT1-rs1130233-AA/GA (p = 0.003), favoring apoptosis induction. In conclusion, SELP and AKT1 polymorphisms may play a role in the risk of cachexia and death in PDAC patients, and should be further evaluated in larger prospective studies.

Molecular mechanisms underlying the role of microRNAs in the chemoresistance of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is an extremely severe disease where the mortality and incidence rates are almost identical. This is mainly due to late diagnosis and limited response to current treatments. The tumor macroenvironment/microenvironment have been frequently reported as the major contributors to chemoresistance in PDAC, preventing the drugs from reaching their intended site of action (i.e., the malignant duct cells). However, the recent discovery of microRNAs (miRNAs) has provided new directions for research on mechanisms underlying response to chemotherapy. Due to their tissue-/disease-specific expression and high stability in tissues and biofluids, miRNAs represent new promising diagnostic and prognostic/predictive biomarkers and therapeutic targets. Furthermore, several studies have documented that selected miRNAs, such as miR-21 and miR-34a, may influence response to chemotherapy in several tumor types, including PDAC. In this review, we summarize the current knowledge on the role of miRNAs in PDAC and recent advances in understanding their role in chemoresistance through multiple molecular mechanisms.

MicroRNAs as emerging biomarkers and therapeutic targets for pancreatic cancer

Despite tremendous efforts from scientists and clinicians worldwide, pancreatic adenocarcinoma (PDAC) remains a deadly disease due to the lack of early diagnostic tools and reliable therapeutic approaches. Consequently, a majority of patients (80%) display an advanced disease that results in a low resection rate leading to an overall median survival of less than 6 months. Accordingly, robust markers for the early diagnosis and prognosis of pancreatic cancer, or markers indicative of survival and/or metastatic disease are desperately needed to help alleviate the dismal prognosis of this cancer. In addition, the discovery of new therapeutic targets is mandatory to design effective treatments. In this review, we will highlight the translational studies demonstrating that microRNAs may soon translate into clinical applications as long-awaited screening tools and therapeutic targets for PDAC.

Molecular pathology of intraductal papillary mucinous neoplasms of the pancreas

Since the first description of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas in the eighties, their identification has dramatically increased in the last decades, hand to hand with the improvements in diagnostic imaging and sampling techniques for the study of pancreatic diseases. However, the heterogeneity of IPMNs and their malignant potential make difficult the management of these lesions. The objective of this review is to identify the molecular characteristics of IPMNs in order to recognize potential markers for the discrimination of more aggressive IPMNs requiring surgical resection from benign IPMNs that could be observed. We briefly summarize recent research findings on the genetics and epigenetics of intraductal papillary mucinous neoplasms, identifying some genes, molecular mechanisms and cellular signaling pathways correlated to the pathogenesis of IPMNs and their progression to malignancy. The knowledge of molecular biology of IPMNs has impressively developed over the last few years. A great amount of genes functioning as oncogenes or tumor suppressor genes have been identified, in pancreatic juice or in blood or in the samples from the pancreatic resections, but further researches are required to use these informations for clinical intent, in order to better define the natural history of these diseases and to improve their management.

Prognostic value of miR-21 in various cancers: an updating meta-analysis

BACKGROUND

Recently, more and more studies investigated the value of microRNA (miRNA) as a diagnostic or prognostic biomarker in various cancers. MiR-21 was found dysregulated in almost all types of cancers. While the prognostic role of miR-21 in many cancers has been studied, the results were not consistent.

METHODS

We performed a meta-analysis to investigate the correlation between miR-21 and survival of general cancers by calculating pooled hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

The pooled results of 63 published studies showed that elevated miR-21 was a predictor for poor survival of general carcinomas, with pooled HR of 1.91 (95%CI: 1.66-2.19) for OS, 1.42 (95% CI: 1.16-1.74) for DFS and 2.2 (95% CI: 1.64-2.96) for RFS/CSS. MiR-21 was also a prognostic biomarker in the patients who received adjuvant therapy, with pooled HR of 2.4 (95%CI: 1.18-4.9) for OS.

CONCLUSIONS

Our results showed that miR-21 could act as a significant biomarker in the prognosis of various cancers. Further studies are warranted before the application of the useful biomarker in the clinical.

Aberrant MicroRNAs in Pancreatic Cancer: Researches and Clinical Implications

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a high rate of mortality and poor prognosis. Numerous studies have proved that microRNA (miRNA) may play a vital role in a wide range of malignancies, including PDAC, and dysregulated miRNAs, including circulating miRNAs, are associated with PDAC proliferation, invasion, chemosensitivity, and radiosensitivity, as well as prognosis. Greater understanding of the roles of miRNAs in PDAC could provide insights into this disease and identify potential diagnostic markers and therapeutic targets. The current review focuses on recent advances with respect to the roles of miRNAs in PDAC and their practical value.

A polymorphism in the promoter is associated with EZH2 expression but not with outcome in advanced pancreatic cancer patients

AIM

EZH2 expression is a prognostic marker in radically resected pancreatic ductal adenocarcinoma (PDAC) patients. Here we investigated its role in locally advanced/metastatic patients, as well as candidate polymorphisms.

MATERIALS & METHODS

EZH2 expression and polymorphisms were evaluated by quantitative reverse transcription PCR in 32 laser microdissected tumors, while polymorphisms were also studied in blood samples from two additional cohorts treated with gemcitabine monotherapy (n = 93) or polychemotherapeutic regimens (n = 247).

RESULTS

EZH2 expression correlated with survival and with the rs6958683 polymorphism in the first cohort of patients, but this polymorphism was not associated with survival in our larger cohorts.

CONCLUSION

EZH2 is a prognostic factor for locally advanced/metastatic PDACs, while candidate polymorphisms cannot predict clinical outcome. Other factors involved in EZH2 regulation, such as miR-101, should be investigated in accessible samples in order to improve the clinical management of advanced PDAC.

MiR-101 suppresses the epithelial-to-mesenchymal transition by targeting ZEB1 and ZEB2 in ovarian carcinoma

Ovarian carcinoma is the most lethal gynecologic malignancy; the majority of patients succumb to the disease within 5 years of diagnosis. The poor survival rate is attributed to diagnosis at advanced stage, when the tumor has metastasized. The epithelial-to-mesenchymal transition (EMT) is a necessary step toward metastatic tumor progression. Through integrated computational analysis, we recently identified a master microRNA (miRNA) network that includes miR-101 and regulates EMT in ovarian carcinoma. In the present study, we characterized the functions of miR-101. Using reporter gene assays, we demonstrated that miR-101 suppressed the expression of the E-cadherin repressors ZEB1 and ZEB2 by directly targeting the 3'-untranslated region (3'UTR) of both ZEB1 and ZEB2. Introduction of miR-101 significantly inhibited EMT and cell migration and invasion. Introducing cDNAs of ZEB1 and ZEB2 without 3'UTR abrogated miR-101-induced EMT alteration, respectively. Our findings showed that miR-101 represents a redundant mechanism for the miR-200 family that regulates EMT through two major E-cadherin transcriptional repressors.

miR-211 modulates gemcitabine activity through downregulation of ribonucleotide reductase and inhibits the invasive behavior of pancreatic cancer cells

Only a subset of radically-resected pancreatic ductal adenocarcinoma (PDAC) patients benefit from gemcitabine-based chemotherapy, thus the identification of novel prognostic factors is essential. In a high-throughput, microRNA (miRNA) array, miR-211 emerged as the best discriminating miRNA, with high expression associated with long survival. Here, we further explored the biological role of miRNA-211 in gemcitabine activity in the human PDAC cells (SUIT-2) subclones SUIT2-007 and SUIT2-028. Our results showed that miR-211 was expressed differentially in PDAC cells characterized by differential metastatic capability. In particular, S2-028 with lower metastatic ability had a higher expression of miR-211, compared to the S2-007 with higher metastatic capacity. Enforced expression of miR-211 via pre-miR-211 significantly reduced cell migration and invasion (e.g., 40% reduction of invasion of SUIT2 cells, compared to control; p<.05). Moreover, we demonstrated that induction of the miR-211 expression in the cells increased the sensitivity to gemcitabine and reduced the expression of its target ribonucleotide reductase subunit 2 (RRM2). In conclusion, miR-211 functional analyses suggested the role of RRM2 as a target of miR-211 in the modulation of gemcitabine sensitivity. Moreover, inhibition of cell migration and invasion might explain the less aggressive behavior of pancreatic cancer cells with higher expression levels of miR-211.

Endoscopically acquired pancreatic cyst fluid microRNA 21 and 221 are associated with invasive cancer

OBJECTIVES

Pancreatic cysts are a group of lesions with heterogeneous malignant potential. Currently, there are no reliable biomarkers to aid in cyst diagnosis and classification. The objective of this study was to identify potential microRNA (miR) biomarkers in endoscopically acquired pancreatic cyst fluid that could be used to distinguish between benign, premalignant, and malignant cysts.

METHODS

A list of candidate miRs was developed using a whole-genome expression array analysis of pancreatic cancer (pancreatic ductal adenocarcinoma) and nonmalignant samples overlapped with existing literature and predicted gene targets. Endoscopically acquired pancreatic cyst fluid samples were obtained from a group of 38 patients who underwent cyst fluid aspiration and surgical resection. Selected miR expression levels in cyst fluid samples were assessed by quantitative real-time-PCR. Additionally, in situ hybridization (ISH) on corresponding cyst tissue samples was performed to identify the source and validate the expression level of fluid miRs.

RESULTS

Of the six miRs that were profiled in the study, two showed differential expression in malignant cysts. miR-221 was expressed at significantly higher levels in malignant cysts compared with benign or premalignant cysts (P=0.05). miR-21 was also expressed at significantly higher levels in malignant cysts (P<0.01). Additionally, the expression of miR-21 was significantly higher in premalignant cysts than benign cysts (P=0.03). The differential expression of miR-21 among cyst categories was confirmed by ISH.

CONCLUSIONS

In this small single-center study, miRs are potential pancreatic cyst fluid diagnostic biomarkers. In particular, miR-21 is identified as a candidate biomarker to distinguish between benign, premalignant, and malignant cysts. Additionally miR-221 may be of use in the identification of more advanced malignant disease.

Real-time monitoring of miRNA function in pancreatic cell lines using recombinant AAV-based miRNA Asensors

BACKGROUND

MicroRNAs (miRNAs) are reportedly involved in pancreatic ductal adenocarcinoma (PDAC) development. Current methods do not allow us to reliably monitor miRNA function. Asensors are adeno-associated virus (AAV) vector miRNA sensors for real-time consecutive functional monitoring of miRNA profiling in living cells.

METHODS

miR-200a, -200b, -21, -96, -146a, -10a, -155, and -221 in three PDAC cell lines (BxPC-3, CFPAC-1, SW1990), pancreatic epithelioid carcinoma cells (PANC-1), and human pancreatic nestin-expressing cells (hTERT-HPNE) were monitored by Asensors. Subsequently, the real-time consecutive functional profile of all miRNAs was evaluated.

RESULTS

Selected miRNAs were detectable in all cell lines with high sensitivity and reproducibility. In the three PDAC cell lines, BxPC-3, CFPAC-1, and SW1990, the calibrated signal unit of the eight miRNAs Asensors was significantly lower than that of the Asensor control. However, in PANC-1 cells, miR-200a and -155 showed upregulation of target gene expression at 24 hours after infection with the sensors; at 48 hours, miR-200b and -155 displayed upregulation of reporter expression; and at 72 hours, reporter gene expression was upregulated by miR-200a and -200b. The result that miRNA could upregulate gene expression was further confirmed in miR-155 of hTERT-HPNE cells. Furthermore, miRNA activity varied among cell/tissue types and time.

CONCLUSION

It is possible that miRNA participates in the pathophysiology of pancreatic cancer, but the current popular methods do not accurately reveal the real-time miRNA function. Thus, this report provided a convenient, accurate, and sensitive approach to miRNA research.

Distinct miRNA profiles are associated with malignant transformation of pancreatic cystic tumors revealing potential biomarkers for clinical use

Pancreatic cysts are now being detected more frequently owing to increased recognition and the liberal use of cross-sectional imaging. There is a spectrum of pancreatic cystic lesions ranging from the completely benign inflammatory to the highly malignant. Pancreatic cystic tumors, especially those with a mucinous epithelial lining such as the intraductal papillary mucinous neoplasms (IPMNs), have the potential to become malignant. The evaluated paper provides further evidence for miRNAs as diagnostic biomarkers for detecting dysplastic and malignant change in IPMNs, which may be useful for future clinical decision making. IPMNs of varying degrees of dysplasia, as well as IPMN with carcinoma, pancreatic ductal adenocarcinoma and normal pancreas samples were examined by microarray. Upregulation of miR-21, miR-155 and miR-708 was found to occur during IPMN malignant transformation. Here, the authors evaluate the published miRNA profiles of premalignant pancreatic lesions in order to consolidate these data.