Circulating plasma MiR-141 is a novel biomarker for metastatic colon cancer and predicts poor prognosis

Evaluation and identification of microRNA-106 in the diagnosis of cancer: a meta-analysis

Recently, extensive research has identified the non-invasive and cost-effective biomarker microRNA-106 (miR-106) in cancer detection. However, inconsistent results have prevented its usage in clinical. Therefore, we conducted this meta-analysis aimed to systematically determine diagnostic accuracy of miR-106 in distinguishing patients with cancer from cancer-free controls and further evaluate its value serving as a biomarker in clinical. We conducted a systematically literature search in databases (PubMed, web of science, Embase and the Cochrane Library) collecting relevant articles up to July 22th, 2014. The overall diagnostic accuracy of miR-106 was assessed by the following indexes: sensitivity, specificity, PLR, NLR and DOR. The SROC curve with AUC value was also generated for the assessment. Due to the significant heterogeneity, the random effects approach was chosen in our analysis and meta-regression was performed to explore the potential source of it. We also tested potential presence of publication bias using Deeks' funnel plots test. Stata 12.0 statistical software was used for analysis in the present study. Overall, the 11 studies involving 756 cancer patients and 834 controls were considered eligible in our analysis. The results in our work showed that sensitivity of 0.57 (95% CI: 0.44-0.68) and specificity of 0.85 (95% CI: 0.72-0.92), with the under area AUC value of 0.75 (95% CI: 0.71-0.79) for miR-106 assay. Additionally, the combined PLR, NLR and DOR describing the discriminatory ability were 3.7 (95% CI: 2.2-6.2), 0.51 (95% CI: 0.42-0.62) and 7 (95% CI: 4-12) in the present analysis. The results in our meta-analysis showed that miR-106 had moderate accuracy in identifying cancer patients. Thus, further larger-scale prospective studies are needed to improve the diagnostic efficiency and explore the combination of miR-106 and other biomarkers with more pronounced accuracy.

Upregulation of microRNA 181c expression in gastric cancer tissues and plasma

OBJECTIVE

To test the microRNA-181c (miR-181c) expression in tissues and plasma of gastric cancer (GC) cases, analyze any correlations, and explore the possibility of miR-181c as a potential molecular marker for GC diagnosis.

MATERIALS AND METHODS

Relative miR-181c expression levels in cancers and plasma from 30 GC patients was tested using reverse transcription?real-time fluorescent quantitation PCR and compared to that in samples from 30 gastric ulcer and 30 chronic gastritis patients.

RESULTS

The miR-181c expression level in the GC tissues was significantly higher than that in the gastric ulcer and chronic gastritis tissues (P = 0.000), as was the miR-181c expression level in the GC plasma (P = 0.000). We determined that miR-181c expression in GC plasma was positively correlated to its expression in the GC tissues (P = 0.000).

CONCLUSIONS

The expression of miR-181c is upregulated in GC tissues and plasma, and the miR-181c expression level in GC plasma is positively correlated to that in the corresponding cancer tissues. Plasma miR-181c is possibly a new serological marker for GC diagnosis.

MicroRNA dysregulation as a prognostic biomarker in colorectal cancer

Colorectal cancer (CRC) is one of the most potentially curable cancers, yet it remains the fourth most common overall cause of cancer death worldwide. The identification of robust molecular prognostic biomarkers can refine the conventional tumor–node–metastasis staging system, avoid understaging of tumor, and help pinpoint patients with early-stage CRC who may benefit from aggressive treatments. Recently, epigenetic studies have provided new molecular evidence to better categorize the CRC subtypes and predict clinical outcomes. In this review, we summarize recent findings concerning the prognostic potential of microRNAs (miRNAs) in CRC. We first discuss the prognostic value of three tissue miRNAs (miR-21-5p, miR-29-3p, miR-148-3p) that have been examined in multiple studies. We also summarize the dysregulation of miRNA processing machinery DICER in CRC and its association with risk for mortality. We also reviewe the potential application of miRNA-associated single-nucleotide polymorphisms as prognostic biomarkers for CRC, especially the miRNA-associated polymorphism in the KRAS gene. Last but not least, we discuss the microsatellite instability-related miRNA candidates. Among all these candidates, miR-21-5p is the most promising prognostic marker, yet further prospective validation studies are required before it can go into clinical usage.

Circulating miR-199a-3p as a novel serum biomarker for colorectal cancer

Serum microRNAs (miRNAs) have been shown to have potential for cancer diagnosis. The main objective of the present study was to identify a novel serum miRNA biomarker from patients with colorectal cancer (CRC). Microarray analysis of miRNA expression was performed using paired pre-operative and post-operative serum from 10 CRC patients. Expression of two miRNAs (let-7a and miR-199a-3p) was significantly decreased in the post-operative serum when compared to levels in the pre-operative serum (P=0.015 and 0.029, respectively). Quantitative real-time polymerase chain reaction (qRT-PCR) confirmed the decrease in the miRNAs in an extended number (n=30) of paired serum samples. Next, we examined the serum let-7a level in 32 non-cancer patients and 84 CRC patients but we found no significant difference (P=0.120). In contrast, miR199a-3p expression was significantly higher in the CRC patients than that in the non-cancer patients (P=0.016). Furthermore, clinical and pathological survey indicated that high expression of miR-199a-3p was significantly associated with deep wall invasion. Our data suggest that circulating miR-199a-3p could be a novel serum biomarker for CRC.

Forensic miRNA: potential biomarker for body fluids?

In forensic investigation, body fluids represent an important support to professionals when detected, collected and correctly identified. Through many years, various approaches were used, namely serology-based methodologies however, their lack of sensitivity and specificity became difficult to set aside. In order to sidetrack the problem, miRNA profiling surged with a real potential to be used to identify evidences like urine, blood, menstrual blood, saliva, semen and vaginal secretions. MiRNAs are small RNA structures with 20-25 nt whose proprieties makes them less prone to degradation processes when compared to mRNA which is extremely important once, in a crime scene, biological evidences might be exposed to several unfavorable environmental factors. Recently, published studies were able to identify some specific miRNAs, however their results were not always reproducible by others which can possibly be the reflection of different workflow strategies for their profiling studies. Given the current blast of interest in miRNAs, it is important to acknowledge potential limitations of miRNA profiling, yet, the lack of such studies are evident. This review pretends to gather all the information to date and assessed a multitude of factors that have a potential aptitude to discrediting miRNA profiling, such as: methodological approaches, environmental factors, physiological conditions, gender, pathologies and samples storage. It can be asserted that much has yet to be made, but we pretend to highlight a potential answer for the ultimate question: Can miRNA profiling be used as the forensic biomarker for body fluids identification?

MiR-198 represses tumor growth and metastasis in colorectal cancer by targeting fucosyl transferase 8

In this study we investigated the biological role and mechanism of miR-198 in colorectal carcinoma (CRC). MiR-198 expression was shown to exhibit a strongly negative correlation with lymph node invasion, distant metastasis and patient survival in examinations of colorectal cancer tissues and paired normal colorectal mucosa tissues. fucosyl transferase 8 (FUT8) was identified as a potential target of miR-198 in bioinformatics analysis and luciferase reporter assays. Overexpression of miR-198 in CRC cell lines decreased FUT8 levels as shown by immunofluorescence analysis, and inhibited cell proliferation, migration, and invasion. These anti-tumor phenotypes were rescued by reconstitution of FUT8 expression. Furthermore, miR-198 was shown to target the 3′UTR of FUT8 directly to downregulate FUT8 expression at both mRNA and protein levels in qRT-PCR and Western blot analyses, respectively. In vivo, restoration of miR-198 significantly inhibited xenograft growth and invasion of CRC tumors in nude mice. Therefore, it could be concluded that miR-198 suppresses the proliferation and invasion of CRC by directly targeting FUT8.

MicroRNAome genome: a treasure for cancer diagnosis and therapy

The interplay between abnormalities in genes coding for proteins and noncoding microRNAs (miRNAs) has been among the most exciting yet unexpected discoveries in oncology over the last decade. The complexity of this network has redefined cancer research as miRNAs, produced from what was once considered "genomic trash," have shown to be crucial for cancer initiation, progression, and dissemination. Naturally occurring miRNAs are very short transcripts that never produce a protein or amino acid chain, but act by regulating protein expression during cellular processes such as growth, development, and differentiation at the transcriptional, posttranscriptional, and/or translational level. In this review article, miRNAs are presented as ubiquitous players involved in all cancer hallmarks. The authors also describe the most used methods to detect their expression, which have revealed the identity of hundreds of miRNAs dysregulated in cancer cells or tumor microenvironment cells. Furthermore, the role of miRNAs as hormones and as reliable cancer biomarkers and predictors of treatment response is discussed. Along with this, the authors explore current strategies in designing miRNA-targeting therapeutics, as well as the associated challenges that research envisions to overcome. Finally, a new wave in molecular oncology translational research is introduced: the study of long noncoding RNAs.

Cell-free nucleic acids as noninvasive biomarkers for colorectal cancer detection

Cell-free nucleic acids (CFNA) have been reported by several authors in blood, stool, and urine of patients with colorectal cancer (CRC). These genetic biomarkers can be an indication of neoplastic colorectal epithelial cells, and can thus potentially be used as noninvasive tests for the detection of the disease in CRC patients and monitor their staging, without the need to use heavier and invasive tools. In a number of test-trials, these genetic tests have shown the advantage of non-invasiveness, making them well accepted by most of the patients, without major side effects. They have also shown a promising sensitivity and specificity in the detection of malignant and premalignant neoplasms. Moreover, costs for performing such tests are very low. Several studies reported and confirmed the proof of the principle for these genetic tests for screening, diagnosis, and prognosis; the main challenge of translating this approach from research to clinical laboratory is the validation from large and long-term randomized trials to prove sustainable high sensitivity and specificity. In this paper, we present a review on the noninvasive genetics biomarkers for CRC detection described in the literature and the challenges that can be encountered for validation processes.

DNA methylation and microRNA biomarkers for noninvasive detection of gastric and colorectal cancer

Cancer initiation and progression is controlled by both genetic and epigenetic events. Epigenetics refers to the study of mechanisms that alter gene expression without permanently altering the DNA sequence. Epigenetic alterations are reversible and heritable, and include changes in histone modifications, DNA methylation, and non-coding RNA-mediated gene silencing. Disruption of epigenetic processes can lead to altered gene function and malignant cellular transformation. Aberrant epigenetic modifications occur at the earliest stages of neoplastic transformation and are now believed to be essential players in cancer initiation and progression. Recent advances in epigenetics have not only offered a deeper understanding of the underlying mechanism(s) of carcinogenesis, but have also allowed identification of clinically relevant putative biomarkers for the early detection, disease monitoring, prognosis and risk assessment of cancer patients. At this moment, DNA methylation and non-coding RNA including with microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) represent the largest body of available literature on epigenetic biomarkers with the highest potential for cancer diagnosis. Following identification of cell-free nucleic acids in systematic circulation, increasing evidence has demonstrated the potential of cell-free epigenetic biomarkers in the blood or other body fluids for cancer detection. In this article, we summarize the current state of knowledge on epigenetic biomarkers - primarily DNA methylation and non-coding RNAs - as potential substrates for cancer detection in gastric and colorectal cancer, the two most frequent cancers within the gastrointestinal tract. We also discuss the obstacles that have limited the routine use of epigenetic biomarkers in the clinical settings and provide our perspective on approaches that might help overcome these hurdles, so that these biomarkers can be readily developed for clinical management of cancer patients.

MicroRNAs in soft tissue sarcomas: overview of the accumulating evidence and importance as novel biomarkers

Sarcomas are distinctly heterogeneous tumors and a variety of subtypes have been described. Although several diagnostic explorations in the past three decades, such as identification of chromosomal translocation, have greatly improved the diagnosis of soft tissue sarcomas, the unsolved issues, including the limited useful biomarkers, remain. Emerging reports on miRNAs in soft tissue sarcomas have provided clues to solving these problems. Evidence of circulating miRNAs in patients with soft tissue sarcomas and healthy individuals has been accumulated and is accelerating their potential to develop into clinical applications. Moreover, miRNAs that function as novel prognostic factors have been identified, thereby facilitating their use in miRNA-targeted therapy. In this review, we provide an overview of the current knowledge on miRNA deregulation in soft tissue sarcomas, and discuss their potential as novel biomarkers and therapeutics.

Role of micro-RNA in colorectal cancer screening

MicroRNAs are involved in carcinogenesis through postranscriptional gene regulatory activity. These molecules are involved in various physiological and pathological functions, such as apoptosis, cell proliferation and differentiation, which indicates their functionality in carcinogenesis as tumour suppressor genes or oncogenes. Several studies have determined the presence of microRNAs in different neoplastic diseases such as colon, prostate, breast, stomach, pancreas, and lung cancer. There are promising data on the usefulness of quantifying microRNAs in different organic fluids and tissues. We have conducted a review of the determinations of microRNAs in the diagnosis of colorectal cancer.

Molecular biomarkers for the detection of metastatic colorectal cancer cells

Approximately half of all patients with colorectal cancer develop local recurrence or distant metastasis during the course of their illness. Recently, the molecular detection of metastatic cancer cells in various types of clinical samples, such as lymph nodes, bone marrow, peripheral blood, and peritoneal lavage fluid, has been investigated as a potential prognostic marker. The prognostic value of molecular tumor cell detection was independent of the type of detection method used. As assays become more sensitive and quantitative, a more thorough assessment of the cancer status of patients will be based on molecular markers alone. At present, it is difficult to conclude that one specific molecular marker is superior to others. Comparative analyses are recommended to assess the prognostic impact of molecular analyses in the same patient and determine the biomarkers that provide the most accurate prognostic information.

miR-141 and miR-200c as markers of overall survival in early stage non-small cell lung cancer adenocarcinoma

Background

Several treatments in non-small cell lung cancer (NSCLC) are histology-dependent, and the need for histology-related markers is increasing. MicroRNAs (miRNAs) are promising molecular markers in multiple cancers and show differences in expression depending on histological subtype. The miRNA family miR-200 has been associated with the regulation of epithelial-mesenchymal (EMT)/mesenchymal-epithelial transition (MET). EMT involves profound phenotypic changes that include the loss of cell-cell adhesion, the loss of cell polarity, and the acquisition of migratory and invasive properties that facilitates metastasis. A dual role for the miR-200 family in the prognosis of several tumors has been related to tumor cell origin. However, the prognostic role and function of miR-200 family in early-stage NSCLC adenocarcinoma and squamous cell carcinoma (SCC) have not been well established.

Methods

miRNA expression was determined using TaqMan assays in 155 tumors from resected NSCLC patients. Functional studies were conducted in three NSCLC cell lines: H23, A-549 and HCC-44.

Results

High miR-200c expression was associated with shorter overall survival (OS) in the entire cohort (p = 0.024). High miR-200c (p = 0.0004) and miR-141 (p = 0.009) expression correlated with shorter OS in adenocarcinoma – but not in SCC. In the multivariate analysis, a risk score based on miR-141 and miR-200c expression emerged as an independent prognostic factor for OS in the entire cohort (OR, 2.787; p = 0.033) and in adenocarcinoma patients (OR, 10.649; p = 0.002). Functional analyses showed that miR-200c, was related to mesenchymal-epithelial transition (MET) and affected cell migration and E-cadherin levels, while overexpression of miR-141 reduced KLF6 protein levels and produced an increase of secretion of VEGFA in vitro (H23, p = 0.04; A-549, p = 0.03; HCC-44, p = 0.02) and was associated with higher blood microvessel density in patient tumor samples (p<0.001).

Conclusion

High miR-141 and miR-200c expression are associated with shorter OS in NSCLC patients with adenocarcinoma through MET and angiogenesis.

The new world of RNAs

One of the major developments that resulted from the human genome sequencing projects was a better understanding of the role of non-coding RNAs (ncRNAs). NcRNAs are divided into several different categories according to size and function; however, one shared feature is that they are not translated into proteins. In this review, we will discuss relevant aspects of ncRNAs, focusing on two main types: i) microRNAs, which negatively regulate gene expression either by translational repression or target mRNA degradation, and ii) small interfering RNAs (siRNAs), which are involved in the biological process of RNA interference (RNAi). Our knowledge regarding these two types of ncRNAs has increased dramatically over the past decade, and they have a great potential to become therapeutic alternatives for a variety of human conditions.

miR-345 in metastatic colorectal cancer: a non-invasive biomarker for clinical outcome in non-KRAS mutant patients treated with 3rd line cetuximab and irinotecan

Introduction

MicroRNAs (miRNAs) have important regulatory functions in cellular processes and have shown promising potential as prognostic markers for disease outcome in patients with cancer. The aim of the present study was to find miRNA expression profiles in whole blood that were prognostic for overall survival (OS) in patients with metastatic colorectal cancer (mCRC) treated with cetuximab and irinotecan.

Methods

From 138 patients with mCRC in 3^rd line therapy with cetuximab and irinotecan in a prospective phase II study, 738 pretreatment miRNAs were isolated and profiled from whole blood using the TaqMan MicroRNA Array v2.0. Mutation status of KRAS, BRAF, and PI3KCA was known.

Results

After Bonferroni adjustment, 6 miRNAs: (miR-345, miR-143, miR-34a*, miR-628-5p, miR-886-3p and miR-324-3p), were found associated with short OS. miR-345 was the strongest prognostic miRNA, significant in the full cohort and in the non-KRAS mutant population. miR-345, as a continuous variable in the full cohort, resulted in a hazard ratio (HR) of 2.38 per IQR (CI 95%: 1.8–3.1, P-value = 2.86e−07, Bonferroni adjusted, univariable analysis) and a HR = 1.75 per IQR (CI 95%: 1.24–2.48, P-Wald = 1.45e-03) in the multivariable analysis adjusted for gender, age, KRAS, PI3KCA and performance status. miR-345 was prognostic in progression-free survival (PFS) with a HR = 1.63 per IQR (CI 95%: 1.25–2.114, P-Wald = 2.92e-4) in the multivariable analysis. In addition, high miR-345 expression was associated with lack of response to treatment with cetuximab and irinotecan.

Conclusion

We identified miR-345 in whole blood as a potential biomarker for clinical outcome. MiR-345 was a single prognostic biomarker for both OS and PFS in all patients and also in the non-KRAS mutant population.

MicroRNAs in brain metastases: potential role as diagnostics and therapeutics

Brain metastases remain a daunting adversary that negatively impact patient survival. Metastatic brain tumors affect up to 45% of all cancer patients with systemic cancer and account for ~20% of all cancer-related deaths. A complex network of non-coding RNA molecules, microRNAs (miRNAs), regulate tumor metastasis. The brain micro-environment modulates metastatic tumor growth; however, defining the precise genetic events that promote metastasis in the brain niche represents an important, unresolved problem. Understanding these events will reveal disease-based targets and offer effective strategies to treat brain metastases. Effective therapeutic strategies based upon the biology of brain metastases represent an urgent, unmet need with immediate potential for clinical impact. Studies have demonstrated the ability of miRNAs to distinguish normal from cancerous cells, primary from secondary brain tumors, and correctly categorize metastatic brain tumor tissue of origin based solely on miRNA profiles. Interestingly, manipulation of miRNAs has proven effective in cancer treatment. With the promise of reduced toxicity, increased efficacy and individually directed personalized anti-cancer therapy, using miRNA in the treatment of metastatic brain tumors may prove very useful and improve patient outcome. In this review, we focus on the potential of miRNAs as diagnostic and therapeutic targets for the treatment of metastatic brain lesions.

DNA methylation and cancer development: molecular mechanism

DNA methylation is a significant regulator of gene expression, and its role in carcinogenesis recently has been a subject of remarkable interest. The aim of this review is to analyze the mechanism and cell regulatory effects of both hypo- and hyper-DNA methylation on cancer. In this review, we report new developments and their implications regarding the effects of DNA methylation on cancer development. Indeed, alteration of the pattern of DNA methylation has been a constant finding in cancer cells of the same type and differences in the pattern of DNA methylation not only occur in a variety of tumor types, but also in developmental processes Furthermore, the pattern of histone modification appears to be a predicator of the risk of recurrence of human cancers. It is well known that hypermethylation represses transcription of the promoter sections of tumor-suppressor genes leading to gene silencing. However, hypomethylation also has been identified as a cause of oncogenesis. Furthermore, experiments concerning the mechanism of methylation and its control have led to the discovery of many regulatory enzymes and proteins. This review reports on methods developed for the detection of 5-hydroxymethylcytosine methylation at the 5-methylcytosine of protein domains in the CpG context compared to non-methylated DNA, histone modification, and microRNA change.

miRNA panels as biomarkers for bladder cancer

Aim: Specific miRNA profiles have been identified for several samples from patients with bladder cancer. The results are not always congruent and partly contradictory. A comparison of published data was performed to select potential markers. Materials & methods: A literature search in PubMed identified 79 articles published prior to June 2013. Reports regarding the detection of miRNAs in urine and blood have rarely been published; to date, nine respectively three articles are available. Results: The comparison of published data proved the utility of miRNAs as diagnostic and prognostic indicators of bladder cancer. In urine samples from bladder cancer patients, seven miRNAs were concordantly expressed with tumor tissues. Conclusion: Standardization is strictly required in pre-analytics and methods of miRNA measurements.

miRNA microarray reveals specific expression in the peripheral blood of glioblastoma patients

MicroRNAs (miRNAs) are frequently dysregulated in glioblastoma (GBM) patients. It has been discovered that highly stable extracellular miRNAs circulate in the blood of both healthy individuals and patients. miRNAs in serum of patients with GBM and normal controls were analyzed by microarray analysis. The relevant bioinformatic analysis of the predicted target genes (gene ontology, pathway, gene network analysis) were performed. The miRNA microarray reveals differentially expressed miRNAs in serum between the GBM and normal controls. Of the 752 miRNAs, 115 miRNAs were upregulated in the GBM group, and 24 miRNAs were downregulated (fold change ≥2.0, P<0.01). By further analysis, we found that miR-576-5p, miR-340 and miR-626 were significantly overexpressed, but miR-320, let-7g-5p and miR-7-5P showed significantly low expression in GBM patients. By further bioinformatic analysis, we found that they possibly play important roles in the regulation of glioma signaling pathways. In summary, the six miRNAs are significant distinct in the peripheral blood of patients with GBM pathologies. These data suggest that the miRNA profile of the peripheral blood may serve as a new biomarker for glioma diagnosis with high specificity and sensitivity.

MicroRNA in gastrointestinal cancer: a step closer to reality

Despite significant strides in understanding molecular pathogenesis of cancer, gastrointestinal malignancy (gastric, colorectal, pancreatic, and liver) still ranks among the leading causes of cancer-related mortality and morbidity worldwide. One of the key clinical challenges in effectively reducing disease burden associated with gastrointestinal neoplasia stems from late diagnosis, underscoring the need for early detection, risk assessment, and intervention. Currently available screening approaches are inadequate, and the development of accurate noninvasive molecular biomarkers is very much needed, microRNAs (miRNAs) are short (20-24 nucleotides in length) noncoding RNAs that have emerged as important translational gene regulators in cancer cells. In contrast to genetic markers, miRNAs have a cancer-specific expression pattern. They are present in a remarkably stable form and can be detected in a wide variety of body fluids including blood and feces. These properties make them attractive cancer biomarker targets. Although development of miRNA biomarkers is still in its early stages, burgeoning evidence supports their potential use for development as markers for early detection, prognosis, and prediction of disease recurrence and therapeutic outcome in gastrointestinal cancers. In the future, it is likely that miRNA biomarkers will revolutionize personalized medicine and mitigate disease burden associated with gastrointestinal cancers.

Serum miR-200c is a novel prognostic and metastasis-predictive biomarker in patients with colorectal cancer

OBJECTIVE

To evaluate the ability of epithelial-to-mesenchymal transition-related microRNAs (miRNAs) as serum biomarkers for prognosis and prediction of metastasis in patients with colorectal cancer (CRC).

BACKGROUND

Epithelial-to-mesenchymal transition-related miRNAs drive CRC progression and metastasis. However, their potential as serum biomarkers in CRC has not been studied.

METHODS

This was a 3-phase study using 446 colorectal specimens. In the first phase, we selected candidate miRNAs associated with metastasis by analyzing the expression of 4 miR-200 family members (miR-200b, -200c, -141, and -429) in serum samples from 12 patients with stage I and IV CRC. The second phase involved independent validation of candidate miRNAs in serum from 182 patients with CRC and 24 controls. Finally, we analyzed expression in matched 156 tumor tissues from 182 patients with CRC and an independent set of 20 matched primary CRC and corresponding liver metastases to identify the source of circulating miRNAs.

RESULTS

After initial screening, miR-200c was selected as the candidate serum miRNA best associated with metastasis. Validation analysis revealed that serum miR-200c levels were significantly higher in stage IV than in stage I-III CRCs. High serum miR-200c demonstrated a significant positive correlation with lymph node metastasis, distant metastasis, and prognosis (P = 0.0026, P = 0.0023, and P = 0.0064, respectively). More importantly, serum miR-200c was an independent predictor for lymph node metastasis (odds ratio: 4.81, 95% confidence interval: 1.98-11.7, P = 0.0005) and tumor recurrence (hazard ratio: 4.51, 95% confidence interval: 1.56-13.01, P = 0.005) and emerged as an independent prognostic marker for CRC (hazard ratio: 2.67, 95% confidence interval: 1.28-5.67, P = 0.01).

CONCLUSIONS

Serum miR-200c has strong potential to serve as a noninvasive biomarker for CRC prognosis and predicting metastasis.

Role of microRNA in epithelial to mesenchymal transition and metastasis and clinical perspectives

The microRNAs (miRNAs) are a class of small, 20–22 nucleotides in length, endogenously expressed noncoding RNAs that regulate multiple targets posttranscriptionally. Interestingly, miRNAs have emerged as regulators of most physiological and pathological processes, including metastatic tumor progression, in part by controlling a reversible process called epithelial-to-mesenchymal transition (EMT). The activation of EMT increases the migratory and invasive properties fundamental for tumor cell spread while activation of the reverse mesenchymal-to-epithelial transition is required for metastasis outgrowth. The EMT triggering leads to the activation of a core of transcription factors (EMT-TFs) – SNAIL1/SNAIL2, bHLH (E47, E2-2, and TWIST1/TWIST2), and ZEB1/ZEB2 – that act as E-cadherin repressors and, ultimately, coordinate EMT. Recent evidence indicates that several miRNAs regulate the expression of EMT-TFs or EMT-activating signaling pathways. Interestingly, some miRNAs and EMT-TFs form tightly interconnected negative feedback loops that control epithelial cell plasticity, providing self-reinforcing signals and robustness to maintain the epithelial or mesenchymal cell status. Among the most significant feedback loops, we focus on the ZEB/miR-200 and the SNAIL1/miR-34 networks that hold a clear impact in the regulation of the epithelial-mesenchymal state. Recent insights into the p53 modulation of the EMT-TF/miRNA loops and epigenetic regulatory mechanisms in the context of metastasis dissemination will also be discussed. Understanding the regulation of EMT by miRNAs opens new avenues for the diagnosis and prognosis of tumors and identifies potential therapeutic targets that might help to negatively impact on metastasis dissemination and increasing patient survival.

Advances in epigenetic biomarker research in colorectal cancer

Colorectal cancer (CRC) causes approximately 600000 deaths annually and is the third leading cause of cancer mortality worldwide. Despite significant advancements in treatment options, CRC patient survival is still poor owing to a lack of effective tools for early diagnosis and a limited capacity for optimal therapeutic decision making. Since there exists a need to find new biomarkers to improve diagnosis of CRC, the research on epigenetic biomarkers for molecular diagnostics encourages the translation of this field from the bench to clinical practice. Epigenetic alterations are thought to hold great promise as tumor biomarkers. In this review, we will primarily focus on recent advances in the study of epigenetic biomarkers for colorectal cancer and discuss epigenetic biomarkers, including DNA methylation, microRNA expression and histone modification, in cancer tissue, stool, plasma, serum, cell lines and xenografts. These studies have improved the chances that epigenetic biomarkers will find a place in the clinical practices of screening, early diagnosis, prognosis, therapy choice and recurrence surveillance for CRC patients. However, these studies have typically been small in size, and evaluation at a larger scale of well-controlled randomized clinical trials is the next step that is necessary to increase the quality of epigenetic biomarkers and ensure their widespread clinical use.

MicroRNAs in colorectal cancer as markers and targets: Recent advances

MicroRNAs are evolutionarily conserved small non-coding RNA molecules encoded by eukaryotic genomic DNA, and function in post-transcriptional regulation of gene expression via base-pairing with complementary sequences in target mRNAs, resulting in translational repression or degradation of target mRNAs. They represent one of the major types of epigenetic modification and play important roles in all aspects of cellular activities. Altered expression of microRNAs has been found in various human diseases including cancer. Many efforts have been made to discover the characteristic microRNA expression profiles, to understand the roles of aberrantly expressed microRNAs and underlying mechanisms in different cancers. With the application of DNA microarray, real-time quantitative polymerase chain reaction and other molecular biology techniques, increasing evidence has been accumulated which reveal that aberrant microRNAs can be detected not only intracellularly within the cancer cells, but also extracellularly in plasma of patients, postulating the potential of aberrant microRNAs as promising diagnostic/prognostic markers and attracting therapeutic targets. This review is intended to provide the most recent advances in microRNA studies in one of the most common cancers, colorectal cancer, especially the identification of those specifically altered microRNAs in colorectal cancer, validation for their relevance to clinical pathological parameters of patients, functional analyses and potential applications of these microRNAs.

Use of blood-based biomarkers for early diagnosis and surveillance of colorectal cancer

Early screening for colorectal cancer (CRC) holds the key to combat and control the increasing global burden of CRC morbidity and mortality. However, the current available screening modalities are severely inadequate because of their high cost and cumbersome preparatory procedures that ultimately lead to a low participation rate. People simply do not like to have colonoscopies. It would be ideal, therefore, to develop an alternative modality based on blood biomarkers as the first line screening test. This will allow for the differentiation of the general population from high risk individuals. Colonoscopy would then become the secondary test, to further screen the high risk segment of the population. This will encourage participation and therefore help to reach the goal of early detection and thereby reduce the anticipated increasing global CRC incidence rate. A blood-based screening test is an appealing alternative as it is non-invasive and poses minimal risk to patients. It is easy to perform, can be repeated at shorter intervals, and therefore would likely lead to a much higher participation rate. This review surveys various blood-based test strategies currently under investigation, discusses the potency of what is available, and assesses how new technology may contribute to future test design.

Prognostic value of circulating microRNA-21 in digestive system cancers: a meta-analysis

Circulating microRNAs show aberrant expression in patients with cancer. The aim of this study was to investigate the prognostic value of circulating microRNA-21 (miR-21) in digestive system cancers.

METHODS

All the eligible studies were searched by Medline and EMBASE. The hazard ratios (HRs) for overall survival (OS), which compared the expression levels of circulating miR-21 in patients with digestive cancer was extracted and estimated. Pooled HRs and 95% confidence intervals (CI) were calculated. Then a meta-analysis was performed to clarify the prognostic value of the miR-21.

RESULTS

A total of seven studies involving 907 subjects were included. The results suggested that higher circulating miR-21 could predict worse OS outcome with the pooled HR of 2.19 (95% CI 1.01-4.75, P = 0.05) in digestive system cancers. Subgroup analysis by ethnicity indicated circulating miR-21 was associated with OS in patients with digestive cancer among Asians with the pooled HR of 2.90 (95% CI 1.30-6.45, P = 0.009). However, subgroup analysis by digestive system site revealed that there is no associated with OS in patients with colorectal cancer with the pooled HR of 1.34 (95% CI 0.45-4.00, P = 0.60).

CONCLUSION

The present findings suggest that circulating miR-21 is associated with poor survival in patients with digestive cancer and could be a prognostic biomarker for those patients.

Circulating exosomal microRNAs as biomarkers of colon cancer

Purpose

Exosomal microRNAs (miRNAs) have been attracting major interest as potential diagnostic biomarkers of cancer. The aim of this study was to characterize the miRNA profiles of serum exosomes and to identify those that are altered in colorectal cancer (CRC). To evaluate their use as diagnostic biomarkers, the relationship between specific exosomal miRNA levels and pathological changes of patients, including disease stage and tumor resection, was examined.

Experimental Design

Microarray analyses of miRNAs in exosome-enriched fractions of serum samples from 88 primary CRC patients and 11 healthy controls were performed. The expression levels of miRNAs in the culture medium of five colon cancer cell lines were also compared with those in the culture medium of a normal colon-derived cell line. The expression profiles of miRNAs that were differentially expressed between CRC and control sample sets were verified using 29 paired samples from post-tumor resection patients. The sensitivities of selected miRNAs as biomarkers of CRC were evaluated and compared with those of known tumor markers (CA19-9 and CEA) using a receiver operating characteristic analysis. The expression levels of selected miRNAs were also validated by quantitative real-time RT-PCR analyses of an independent set of 13 CRC patients.

Results

The serum exosomal levels of seven miRNAs (let-7a, miR-1229, miR-1246, miR-150, miR-21, miR-223, and miR-23a) were significantly higher in primary CRC patients, even those with early stage disease, than in healthy controls, and were significantly down-regulated after surgical resection of tumors. These miRNAs were also secreted at significantly higher levels by colon cancer cell lines than by a normal colon-derived cell line. The high sensitivities of the seven selected exosomal miRNAs were confirmed by a receiver operating characteristic analysis.

Conclusion

Exosomal miRNA signatures appear to mirror pathological changes of CRC patients and several miRNAs are promising biomarkers for non-invasive diagnosis of the disease.

MicroRNAs as therapeutic targets in human cancers

MicroRNAs (miRNAs) are evolutionarily conserved, small, regulatory RNAs that negatively regulate gene expression. Extensive research in the last decade has implicated miRNAs as master regulators of cellular processes with essential role in cancer initiation, progression, and metastasis, making them promising therapeutic tools for cancer management. In this article, we will briefly review the structure, biogenesis, functions, and mechanism of action of these miRNAs, followed by a detailed analysis of the therapeutic potential of these miRNAs. We will focus on the strategies presently used for miRNA therapy; discuss their use and drawbacks; and the challenges and future directions for the development of miRNA-based therapy for human cancers.

Prognostic role of circulating microRNA-21 in cancers: evidence from a meta-analysis

Circulating microRNAs (miRNAs) exhibit altered expression in patients with cancer and could be considered as potential prognostic biomarker of cancer. Here, we performed a meta-analysis to summarize all the results from available studies, aiming to analyze the prognostic role of circulating microRNA-21 (miR-21) in human cancers. Eligible studies were identified from PubMed and EMBASE through multiple search strategies. We extracted and estimated the hazard ratios (HRs) for overall survival (OS), which compared the high and low expression levels of circulating miR-21 in patients with a variety of carcinomas. Pooled HRs and 95 % confidence intervals (CIs) were calculated. Eleven studies with a total of 1,224 patients with various carcinomas were included this meta-analysis. For OS, higher circulating miR-21 expression could significantly predict worse outcome with the pooled HR of 2.11 (95 % CI 1.36-3.26, P = 0.0009). The subgroup analysis suggested that the elevated circulating miR-21 expression was correlated with worse OS in Asian population with the pooled HR of 2.36 (95 % CI 1.61-3.48, P < 0.0001) and digestive system cancers with the pooled HR of 2.19 (95 % CI 1.01-4.75, P = 0.05). The present meta-analysis suggests that circulating miR-21 expression is associated with poor survival in patients with cancer and could be a prognostic biomarker for those patients.

Differential expression of serum miR-126, miR-141 and miR-21 as novel biomarkers for early detection of liver metastasis in colorectal cancer

OBJECTIVE

MicroRNAs (miRNAs) have potential as diagnostic biomarkers in cancer. Evaluation of the association between miRNA expression patterns and early detection of liver metastasis in colorectal cancer (CRC) has not been reported.

METHODS

We investigated the expression of metastasis-associated miRs-31, 335, 206, 141, 126, 200b, 200c, 21, Let7a, Let7b and Let7c in localized, liver-metastatic and other organ-metastatic CRC (OM-CRC). Expressions of target miRNAs in serum were evaluated in 116 consecutive localized CRC (L-CRC), 72 synchronous liver-metastatic CRC (SLM-CRC) and 36 other OM-CRC by quantitative real-time PCR.

RESULTS

Seven of 11 tested miRNAs could be detected from serum. Four miRNAs, miR-126, Let-7a, miR-141 and miR-21 were identified as metastasis-associated miRNAs. Compared with L-CRC, significant up-regulated expression was observed for miR-141 and miR-21 in SLM-CRC and OM-CRC, down-regulated expression was observed for miR-126 in SLM-CRC and OM-CRC, and up-regulated expression of Let-7a in OM-CRC. The receiver operating characteristic (ROC) curve showed serum miR-126 had a cut-off [log10 relative quantity (log10 (RQ))=-0.2005] with 77.78% sensitivity and 68.97% specificity with an area under curve (AUC) of 0.7564, miR-141 had a cut-off (log10 (RQ)=-0.2285) with 86.11% sensitivity and 76.11% specificity with an AUC of 0.8279, and miR-21 had a cut-off (log10 (RQ)=-0.1310) with 73.61% sensitivity and 66.38% specificity with an AUC of 0.7479.

CONCLUSIONS

We identified liver metastasis-associated miRNAs, suggesting serum miR-126, miR-141 and miR-21 may be novel biomarkers for clinical diagnosis of early stage liver-metastatic CRC.

Post-transcriptional regulatory network of epithelial-to-mesenchymal and mesenchymal-to-epithelial transitions

Epithelial-to-mesenchymal transition (EMT) and its reverse process, mesenchymal-to-epithelial transition (MET), play important roles in embryogenesis, stem cell biology, and cancer progression. EMT can be regulated by many signaling pathways and regulatory transcriptional networks. Furthermore, post-transcriptional regulatory networks regulate EMT; these networks include the long non-coding RNA (lncRNA) and microRNA (miRNA) families. Specifically, the miR-200 family, miR-101, miR-506, and several lncRNAs have been found to regulate EMT. Recent studies have illustrated that several lncRNAs are overexpressed in various cancers and that they can promote tumor metastasis by inducing EMT. MiRNA controls EMT by regulating EMT transcription factors or other EMT regulators, suggesting that lncRNAs and miRNA are novel therapeutic targets for the treatment of cancer. Further efforts have shown that non-coding-mediated EMT regulation is closely associated with epigenetic regulation through promoter methylation (e.g., miR-200 or miR-506) and protein regulation (e.g., SET8 via miR-502). The formation of gene fusions has also been found to promote EMT in prostate cancer. In this review, we discuss the post-transcriptional regulatory network that is involved in EMT and MET and how targeting EMT and MET may provide effective therapeutics for human disease.

MiR-141 suppresses the migration and invasion of HCC cells by targeting Tiam1

Background

We have demonstrated that T lymphoma invasion and metastasis 1 (Tiam1) gene is associated with the poor prognosis of patients with hepatocellular carcinoma (HCC), and we used a computational approach to identify miR-141 as a Tiam1-targeting microRNA (miRNA). Here, we explored the function of miR-141 and the relationship between miR-141 and Tiam1 gene in HCC.

Methods

The miR-141 expression in HCC tissues and cell lines was detected and its roles in regulation of HCC cell proliferation, migration and invasion and target gene expression was investigated. Tiam1 was identified as a novel target of miR-141. Ethics statement: our study was approved by the Nanfang Hospital Medical Ethics Committee Ethics statement. Written informed consent was obtained before collection.

Results

Based on in situ hybridization (ISH) analysis, miR-141 was down-regulated in the same HCC samples. Kaplan-Meier analysis demonstrated that patients with low miR-141 expression had poorer overall survival rate than that of the patients with high miR-141 expression. Furthermore, multivariate Cox regression analysis indicated that miR-141 could serve as an independent prognostic factor in HCC. MiR-141 significantly inhibited in vitro cell proliferation, migration and invasion as proved by gain- and loss- of function studies, while the mRNA and protein levels of Tiam1 were reduced in cells over-expressing miR-141. Moreover, Tiam1 treatment antagonized this effect, while knockdown of Tiam1 by Tiam1 short hairpin RNA (shTiam1) induced inhibitory effects.

Conclusions

These findings indicated that miR-141 functions as a tumor suppressor and inhibits the migration and invasion of HCC cells by targeting Tiam1, which may provide novel prognostic and treatment strategies for HCC patients.

Clinical relevance of circulating cell-free microRNAs in cancer

Efficient patient management relies on early diagnosis of disease and monitoring of treatment. In this regard, much effort has been made to find informative, blood-based biomarkers for patients with cancer. Owing to their attributes-which are specifically modulated by the tumour-circulating cell-free microRNAs found in the peripheral blood of patients with cancer may provide insights into the biology of the tumour and the effects of therapeutic interventions. Moreover, the role of microRNAs in the regulation of different cellular processes points to their clinical utility as blood-based biomarkers and future therapeutic targets. MicroRNAs are optimal biomarkers owing to high stability under storage and handling conditions and their presence in blood, urine and other body fluids. In particular, detection of levels of microRNAs in blood plasma and serum has the potential for an earlier cancer diagnosis and to predict prognosis and response to therapy. This Review article considers the latest developments in the use of circulating microRNAs as prognostic and predictive biomarkers and discusses their utility in personalized medicine.

MicroRNAs as potential biomarkers in diseases and toxicology

MiRNAs (microRNAs) are single-stranded non-coding RNAs of approximately 21-23 nucleotides in length whose main function is to inhibit gene expression by interfering with mRNA processes. MicroRNAs suppress gene expression by affecting mRNA (messenger RNAs) stability, targeting the mRNA for degradation, or both. In this review, we have examined how microRNA expression could be altered following exposure to chemicals and how they could represent appropriate tissue and more interestingly circulating biomarkers. Among the key questions before using the microRNA for evaluation of risk toxicity, it remains still to clarify how they could be causally involved in the adverse effects and how stable their changes are.

MicroRNAs and other non-coding RNAs as targets for anticancer drug development

The first cancer-targeted microRNA (miRNA) drug - MRX34, a liposome-based miR-34 mimic - entered Phase I clinical trials in patients with advanced hepatocellular carcinoma in April 2013, and miRNA therapeutics are attracting special attention from both academia and biotechnology companies. Although miRNAs are the most studied non-coding RNAs (ncRNAs) to date, the importance of long non-coding RNAs (lncRNAs) is increasingly being recognized. Here, we summarize the roles of miRNAs and lncRNAs in cancer, with a focus on the recently identified novel mechanisms of action, and discuss the current strategies in designing ncRNA-targeting therapeutics, as well as the associated challenges.

Upregulation of E2F transcription factor 3 is associated with poor prognosis in hepatocellular carcinoma

E2F transcription factor 3 (E2F3), a member of the E2F transcription factor family and a member of the genes involved in the regulation of cell cycle, is an oncogene with strong proliferative potential. E2F3 is involved in many processes and plays important roles in the development of several types of cancer, while its relationship with prognosis in hepatocellular carcinoma (HCC) has yet to be reported. In the present study, based on 4 independent microarray data sets which covered 385 cases of HCC and 327 cases of normal livers retrieved from the Oncomine database, we demonstrated that E2F3 was upregulated at least 1.5-fold and on average 2.3-fold in HCC when compared with normal controls. Comprehensive bioinformatics analysis consisting of protein-protein interaction, gene co-occurrence, microRNA-mRNA interaction and biological process annotation indicated that E2F3 interacted with a large number of genes, proteins and microRNAs which were all associated with poor prognosis in patients with HCC and other types of cancer, suggesting that E2F3 may also serve as a biomarker for poor prognosis. Taken together, for the first time, we show that the overexpression of E2F3 may be associated with unfavorable prognosis in HCC.

Recurrence of early stage colon cancer predicted by expression pattern of circulating microRNAs

Systemic treatment of patients with early-stage cancers attempts to eradicate occult metastatic disease to prevent recurrence and increased morbidity. However, prediction of recurrence from an analysis of the primary tumor is limited because disseminated cancer cells only represent a small subset of the primary lesion. Here we analyze the expression of circulating microRNAs (miRs) in serum obtained pre-surgically from patients with early stage colorectal cancers. Groups of five patients with and without disease recurrence were used to identify an informative panel of circulating miRs using quantitative PCR of genome-wide miR expression as well as a set of published candidate miRs. A panel of six informative miRs (miR-15a, mir-103, miR-148a, miR-320a, miR-451, miR-596) was derived from this analysis and evaluated in a separate validation set of thirty patients. Hierarchical clustering of the expression levels of these six circulating miRs and Kaplan-Meier analysis showed that the risk of disease recurrence of early stage colon cancer can be predicted by this panel of miRs that are measurable in the circulation at the time of diagnosis (P = 0.0026; Hazard Ratio 5.4; 95% CI of 1.9 to 15).

Circulating microRNAs as Promising Tumor Biomarkers

microRNAs (miRNAs) are small, nonprotein-coding RNAs that function as posttranscriptional regulators of target genes. miRNAs are involved in multiple cell differentiation, proliferation, and apoptosis processes that are closely related to tumorigenesis. Circulating miRNAs are promising cancer biomarkers under development with great translational potential in personalized medicine. Here, we describe the origin and function of circulating miRNAs and compare the current new high-throughput technology applied to miRNA quantitation. The latest publications on circulating miRNAs were summarized, indicating that miRNAs are potential biomarkers of diagnosis, prognosis, and treatment response of major cancer types including prostate, breast, lung, colorectal, and hematological cancers. We addressed the strengths and limitations of applying circulating miRNAs in clinical laboratory and several issues associated with the accurate measurement of circulating miRNAs.

MiR-200, a new star miRNA in human cancer

MicroRNAs (miRNAs) are a set of non-coding small RNA molecules in control of gene expression at posttranscriptional/translational level. They not only play crucial roles in normal developmental progress, but also are commonly dysregulated in human diseases, including cancer. MiR-200 is a family of tumor suppressor miRNAs consisting of five members, which are significantly involved in inhibition of epithelial-to-mesenchymal transition (EMT), repression of cancer stem cells (CSCs) self-renewal and differentiation, modulation of cell division and apoptosis, and reversal of chemoresistance. In this article, we summarize the latest findings with regard to the tumor suppressor signatures of miR-200 and the regulatory mechanisms of miR-200 expression. The collected evidence supports that miR-200 is becoming a new star miRNA in study of human cancer.

A plasma microRNA panel for detection of colorectal adenomas: a step toward more precise screening for colorectal cancer

OBJECTIVE

The main objective of this study was to investigate the potential use of circulating microRNAs (miRNAs) as biomarkers of colorectal (CR) adenomas.

BACKGROUND

Detection of precancerous lesions such as CR adenoma is a key to reduce CR cancer (CRC) mortality. There is a great need for accurate, noninvasive biomarkers for detection of CR adenoma and CRC. MiRNAs are non-protein-coding RNAs that regulate gene expression. Our prior work investigated the dysregulation of 5 plasma miRNAs in CRC patients. As intended, we undertook a more comprehensive plasma-miRNA screening study in patients with CR adenoma and CRC.

METHODS

We screened for 380 plasma-miRNAs using microfluidic array technology (Applied BioSystems) in a screening cohort of 12 healthy controls, 9 patients with CR adenomas, and 20 patients with CRC. A panel of the most dysregulated miRNAs (P < 0.05, False Discovery Rate: 5%) was then validated in a blinded cohort of 26 healthy controls, 16 patients with large adenomas, and 45 patients with CRC.

RESULTS

A panel of 8 plasma miRNAs (miR-532-3p, miR-331, miR-195, miR-17, miR-142-3p, miR-15b, miR-532, and miR-652) distinguished polyps from controls with high accuracy [area under curve (AUC) = 0.868 (95% confidence interval [CI]: 0.76-0.98)]. In addition, a panel of 3 plasma miRNAs (miR-431, miR-15b, and miR-139-3p) distinguished Stage IV CRC from controls with an [AUC = 0.896 (95% CI: 0.78-1.0)]. Receiver-operating-characteristic curves of miRNA panels for all CRC versus controls and polyps versus all CRC showed AUC values of 0.829 (95% CI: 0.73-0.93) and 0.856 (95% CI: 0.75-0.97), respectively.

CONCLUSIONS

Plasma miRNAs are reliable, noninvasive, and inexpensive markers for CR adenomas. This miRNA panel warrants study in larger cohorts. Plasma-based assays could provide better screening compliance compared to fecal occult blood or endoscopic screening.

Prognostic significance of microRNA-141 expression and its tumor suppressor function in human pancreatic ductal adenocarcinoma

Increasing evidence shows that dysregulation of microRNAs is correlated with tumor development. This study was performed to determine the expression of miR-141 and investigate its clinical significance in pancreatic ductal adenocarcinoma (PDAC). Taqman quantitative RT-PCR was used to detect miR-141 expressions in 94 PDAC tissues and 16 nontumorous pancreatic tissues. Correlations between miR-141 expression and clinicopathologic features and prognosis of patients were statistically analyzed. The effects of miR-141 expression on growth and apoptosis of PDAC cell line (PANC-1) were determined by MTT, colony formation, and flow cytometry assays. Potential target genes were identified by luciferase reporter and Western blot assays. The expression level of miR-141 in PDAC tissues was significantly lower than that in corresponding nontumorous tissues. Downregulation of miR-141 correlated with poorer pT and pN status, advanced clinical stage, and lymphatic invasion. Also, low miR-141 expression in PDAC tissues was significantly correlated with shorter overall survival, and multivariate analysis showed that miR-141 was an independent prognostic factor for PDAC patients. Further, functional researches suggested that miR-141 inhibits growth and colony formation, and enhances caspase-3-dependent apoptosis in PANC-1 cells by targeting Yes-associated protein-1 (YAP1). Therefore, miR-141 is an independent prognostic factor for PDAC patients, and functions as a tumor suppressor gene by targeting YAP1.

Epigenetic biomarkers in laboratory diagnostics: emerging approaches and opportunities

Epigenetics has emerged as a new and promising field in recent years. Lifestyle, stress, drugs, physiopathological situations and pharmacological interventions have a great impact on the epigenetic code of the cells by altering the methylome, miRNA expression and the covalent histone modifications. Since there exists a need to find new biomarkers and improve diagnosis for several diseases, the research on epigenetic biomarkers for molecular diagnostics encourages the translation of this field from the bench to clinical practice. In this context, deciphering intricate epigenetic modifications involved in several molecular processes is a challenge that will be solved in the near future. In this review, the authors present an overview of the high-throughput technologies and laboratory techniques available for epigenetic studies, and also discuss which of them are more reliable to be used in a clinical diagnostic laboratory. In addition, the authors describe the most promising epigenetic biomarkers in lung, colorectal and prostate cancer, in which most advances have been achieved. Finally, the authors describe epigenetic biomarkers in some rare diseases; these rare syndromes are paradigms for a specific impaired molecular pathway, thus providing valuable information on the discovery of new epigenetic biomarkers.

Plasma miRNAs as diagnostic and prognostic biomarkers for ovarian cancer

Background

Most (70%) epithelial ovarian cancers (EOCs) are diagnosed late. Non-invasive biomarkers that facilitate disease detection and predict outcome are needed. The microRNAs (miRNAs) represent a new class of biomarkers. This study was to identify and validate plasma miRNAs as biomarkers in EOC.

Methodology/Principal Findings

We evaluated plasma samples of 360 EOC patients and 200 healthy controls from two institutions. All samples were grouped into screening, training and validation sets. We scanned the circulating plasma miRNAs by TaqMan low-density array in the screening set and identified/validated miRNA markers by real-time polymerase chain reaction assay in the training set. Receiver operating characteristic and logistic regression analyses established the diagnostic miRNA panel, which were confirmed in the validation sets. We found higher plasma miR-205 and lower let-7f expression in cases than in controls. MiR-205 and let-7f together provided high diagnostic accuracy for EOC, especially in patients with stage I disease. The combination of these two miRNAs and carbohydrate antigen-125 (CA-125) further improved the accuracy of detection. MiR-483-5p expression was elevated in stages III and IV compared with in stages I and II, which was consistent with its expression pattern in tumor tissues. Furthermore, lower levels of let-7f were predictive of poor prognosis in EOC patients.

Conclusions/Significance

Our findings indicate that plasma miR-205 and let-7f are biomarkers for ovarian cancer detection that complement CA-125; let-7f may be predictive of ovarian cancer prognosis.

MicroRNA profile: a promising ancillary tool for accurate renal cell tumour diagnosis

Background:

Renal cell tumours (RCTs) are clinically, morphologically and genetically heterogeneous. Accurate identification of renal cell carcinomas (RCCs) and its discrimination from normal tissue and benign tumours is mandatory. We, thus, aimed to define a panel of microRNAs that might aid in the diagnostic workup of RCTs.

Methods:

Fresh-frozen tissues from 120 RCTs (clear-cell RCC, papillary RCC, chromophobe RCC (chRCC) and oncocytomas: 30 cases each), 10 normal renal tissues and 60 cases of ex-vivo fine-needle aspiration biopsies from RCTs (15 of each subtype validation set) were collected. Expression levels of miR-21, miR-141, miR-155, miR-183 and miR-200b were assessed by quantitative reverse transcription–PCR. Receiver operator characteristic curves were constructed and the areas under the curve were calculated to assess diagnostic performance. Disease-specific survival curves and a Cox regression model comprising all significant variables were computed.

Results:

Renal cell tumours displayed significantly lower expression levels of miR-21, miR-141 and miR-200b compared with that of normal tissues, and expression levels of all miRs differed significantly between malignant and benign RCTs. Expression analysis of miR-141 or miR-200b accurately distinguished RCTs from normal renal tissues, oncocytoma from RCC and chRCC from oncocytoma. The diagnostic performance was confirmed in the validation set. Interestingly, miR-21, miR-141 and miR-155 expression levels showed prognostic significance in a univariate analysis.

Conclusion:

The miR-141 or miR-200b panel accurately distinguishes RCC from normal kidney and oncocytoma in tissue samples, discriminating from normal kidney and oncocytoma, whereas miR-21, miR-141 and miR-155 convey prognostic information. This approach is feasible in fine-needle aspiration biopsies and might provide an ancillary tool for routine diagnosis.

Microenvironmental regulation of cancer metastasis by miRNAs

miRNAs are a class of small, non-coding RNAs that regulate cancer progression, especially the processes of invasion and metastasis. Although earlier studies in metastasis primarily focused on the impact that miRNAs have on the intrinsic properties of cancer cells, recent reports reveal that miRNAs also shape interactions between cancer cells and their associated stroma. In this review, we discuss current known mechanisms by which miRNAs execute their microenvironmental regulation of cancer metastasis, including regulating expression of cell membrane-bound and secreted proteins or directly transmitting mature miRNAs between different cell types. The significance of miRNA-mediated tumor-stroma interactions in regulating metastasis suggests that miRNAs may be a potential therapeutic target.

MicroRNAs and long non-coding RNAs: prospects in diagnostics and therapy of cancer

Background

Non-coding RNAs (ncRNAs) are key regulatory molecules in cellular processes, and are potential biomarkers in many diseases. Currently, microRNAs and long non-coding RNAs are being pursued as diagnostic and prognostic biomarkers, and as therapeutic tools in cancer, since their expression profiling is able to distinguish different cancer types and classify their sub-types.

Conclusions

There are numerous studies confirming involvement of ncRNAs in cancer initiation, development and progression, but have only been recently identified as new diagnostic and prognostic tools. This can be beneficial in future medical cancer treatment options, since ncRNAs are natural antisense interactors included in regulation of many genes connected to survival and proliferation. Research is directed in development of useful markers for diagnosis and prognosis in cancer and in developing new RNA-based cancer therapies, of which some are already in clinical trials.

miRNAs as colorectal cancer biomarkers: current progress and future challenges

SUMMARY Colorectal cancer is a common pathology, accounting for approximately 8% of cancer deaths. The induction of a metastatic cascade heralds a potentially devastating end point with limited curative therapeutic options and early detection is, therefore, crucial. Novel diagnostic and predictive biomarkers are urgently required as current candidates lack sensitivity and specificity, particularly in the context of early disease. miRNAs are a group of short noncoding RNAs which regulate gene expression at a post-transcriptional level and have recently been shown to hold promise as fecal, circulating or tissue biomarkers. This review explores current progress and future challenges in this rapidly expanding field.