Urinary cell-free microRNA-106b as a novel biomarker for detection of bladder cancer

Diagnostic performance of urine and blood microRNAs for bladder cancer: a meta-analysis

OBJECTIVE

To compare and assess the diagnostic value of urine and blood microRNAs(miRNAs) in discriminating bladder cancer (BCa).

METHODS

A total of 45 articles were selected, which included 4050 BCa cases and 3490 controls. Summary receiver operating characteristic (SROC) curve analyses were performed, an area under curve (AUC) was calculated and pooled accuracy was analyzed using Stata 16.0 software.

RESULTS

The AUC, sensitivity, and specificity for urinary miRNAs were 0.88, 0.82, and 0.81, respectively, those for blood miRNAs were 0.91, 0.86, and 0.82. For miR-143, the AUC was 0.88, with 0.79 sensitivity and 0.87 specificity. The results of subgroup analyses and meta-regression suggested the publication year, ethnicity, sample size, miRNAs type, and specimen type were possible sources of heterogeneity. The Deeks funnel plot indicated there was no significant publication bias.

CONCLUSION

Urine and blood-based miRNAs may potentially be promising biomarkers for noninvasive early detection of bladder tumor. The diagnostic accuracy of blood-based miRNAs would be better than those of urine-based ones, and multiple miRNA panels yielded more accurate results than single-miRNA assay. Besides, miR-143 is a promising candidate biomarker for diagnosing BCa. More prospective and standardized studies are required to confirm the future findings.

Diagnostic Strategies for Urologic Cancer Using Expression Analysis of Various Oncogenic Surveillance Molecules—From Non-Coding Small RNAs to Cancer-Specific Proteins

Urinary-tract-related tumors are prone to simultaneous or heterogeneous multiple tumor development within the primary organ. Urologic tumors have a very high risk of recurrence in the long and short term. This may be related to the disruption of homeostasis on the genetic level, such as the induction of genetic mutations due to exposure to various carcinogenic factors and the disruption of cancer suppressor gene functions. It is essential to detect the cancer progression signals caused by genetic abnormalities and find treatment therapies. In this review, we discuss the usefulness of tumor-expressing clinical biomarkers for predicting cancer progression. Furthermore, we discuss various factors associated with disturbed intracellular signals and those targeted by microRNAs, which are representative of non-coding small RNAs.

mRNA-miRNA bipartite networks reconstruction in different tissues of bladder cancer based on gene co-expression network analysis

Bladder cancer (BC) is one of the most important cancers worldwide, and if it is diagnosed early, its progression in humans can be prevented and long-term survival will be achieved accordingly. This study aimed to identify novel micro-RNA (miRNA) and gene-based biomarkers for diagnosing BC. The microarray dataset of BC tissues (GSE13507) listed in the GEO database was analyzed for this purpose. The gene expression data from three BC tissues including 165 primary bladder cancer (PBC), 58 normal looking-bladder mucosae surrounding cancer (NBMSC), and 23 recurrent non-muscle invasive tumor tissues (RNIT) were used to reconstruct gene co-expression networks. After preprocessing and normalization, deferentially expressed genes (DEGs) were obtained and used to construct the weighted gene co-expression network (WGCNA). Gene co-expression modules and low-preserved modules were extracted among BC tissues using network clustering. Next, the experimentally validated mRNA-miRNA interaction information were used to reconstruct three mRNA-miRNA bipartite networks. Reactome pathway database and Gene ontology (GO) was subsequently performed for the extracted genes of three bipartite networks and miRNAs, respectively. To further analyze the data, ten hub miRNAs (miRNAs with the highest degree) were selected in each bipartite network to reconstruct three bipartite subnetworks. Finally, the obtained biomarkers were comprehensively investigated and discussed in authentic studies. The obtained results from our study indicated a group of genes including PPARD, CST4, CSNK1E, PTPN14, ETV6, and ADRM1 as well as novel miRNAs (e.g., miR-16-5p, miR-335-5p, miR-124-3p, and let-7b-5p) which might be potentially associated with BC and could be a potential biomarker. Afterward, three drug-gene interaction networks were reconstructed to explore candidate drugs for the treatment of BC. The hub miRNAs in the mRNA-miRNA bipartite network played a fundamental role in BC progression; however, these findings need further investigation.

Trends in urine biomarker discovery for urothelial bladder cancer: DNA, RNA, or protein?

Urothelial bladder cancer is a complex disease displaying a landscape of heterogenous molecular subtypes, mutation profiles and clinical presentations. Diagnosis and surveillance rely on flexible cystoscopy which has high accuracy, albeit accompanied by a high-cost burden for healthcare providers and discomfort for patients. Advances in "omic" technologies and computational biology have provided insights into the molecular pathogenesis of bladder cancer and provided powerful tools to identify markers for disease detection, risk stratification, and predicting responses to therapy. To date, numerous attempts have been made to discover and validate diagnostic biomarkers that could be deployed as an adjunct to the cystoscopic diagnosis and long-term surveillance of bladder cancer. We report a comprehensive literature analysis using PubMed to assess the changing trends in investigating DNA, RNA, or proteins as diagnostic urinary biomarkers over a period of 5 decades: 1970-2020. A gradual shift has been observed in research away from protein biomarkers to nucleic acids including different classes of RNA, and DNA methylation and mutation markers. Until 2000, publications involving protein biomarker discovery constituted 87% of the total number of research articles with DNA comprising 6% and RNA 7%. Since 2000 the proportion of protein biomarker articles has fallen to 40%, and DNA and RNA studies increased to 32% and 28%, respectively. Clearly research focus, perhaps driven by technological innovation, has shifted from proteins to nucleic acids. We optimistically hypothesise that, following thorough validation, a clinically useful detection test for bladder cancer based on a panel of DNA or RNA markers could become reality within 5-10 years.

Epigenetics of Bladder Cancer: Where Biomarkers and Therapeutic Targets Meet

Bladder cancer (BC) is the most common neoplasia of the urothelial tract. Due to its high incidence, prevalence, recurrence and mortality, it remains an unsolved clinical and social problem. The treatment of BC is challenging and, although immunotherapies have revealed potential benefit in a percentage of patients, it remains mostly an incurable disease at its advanced state. Epigenetic alterations, including aberrant DNA methylation, altered chromatin remodeling and deregulated expression of non-coding RNAs are common events in BC and can be driver events in BC pathogenesis. Accordingly, these epigenetic alterations are now being used as potential biomarkers for these disorders and are being envisioned as potential therapeutic targets for the future management of BC. In this review, we summarize the recent findings in these emerging and exciting new aspects paving the way for future clinical treatment of this disease.

Cluster miRNAs and cancer: Diagnostic, prognostic and therapeutic opportunities

MiRNAs are class of noncoding RNA important for gene expression regulation in many plants, animals and viruses. MiRNA clusters contain a set of two or more miRNA encoding genes, transcribed together as polycistronic miRNAs. Currently, there are approximately 159 miRNA clusters reported in the human genome consisting of miRNAs ranging from two or more miRNA genes. A large proportion of clustered miRNAs resides in and around the fragile sites or cancer associated genomic hotspots and plays an important role in carcinogenesis. Altered expression of miRNA cluster can be pro-tumorigenic or anti-tumorigenic and can be targeted for clinical management of cancer. Over the past few years, manipulation of miRNA clusters expression is attempted for experimental purpose as well as for diagnostic, prognostic and therapeutic applications in cancer. Re-expression of miRNAs by epigenetic therapy, genome editing such as clustered regulatory interspaced short palindromic repeats (CRISPR) and miRNA mowers showed promising results in cancer therapy. In this review, we focused on the potential of miRNA clusters as a biomarker for diagnosis, prognosis, targeted therapy as well as strategies for modulating their expression in a therapeutic context. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA Processing > Processing of Small RNAs RNA in Disease and Development > RNA in Disease Regulatory RNAs/RNAi/Riboswitches > Biogenesis of Effector Small RNAs.

MMP23B expression and protein levels in blood and urine are associated with bladder cancer

Urothelial bladder cancer (UBC) represents a public health problem because of its high incidence/relapse rates. At present, there are no suitable biomarkers for early diagnosis or relapse/progression prognosis. To improve diagnostic accuracy and overcome the disadvantages of current diagnostic strategies, the detection of UBC biomarkers in easily accessible biofluids, such as urine, represents a promising approach compared with painful biopsies. We investigated the levels of MMP23 genes (microarray and qPCR) and protein (western blot and enzyme-linked immunosorbent assay) in a set of samples (blood, plasma and urine) from patients with UBC and controls as biomarkers for this cancer. MMP23B and its pseudogene MMP23A resulted downregulated in blood cells from UBC compared with controls (66 cases, 70 controls; adjusted P-value = 0.02 and 0.03, respectively). In contrast, MMP23B protein levels in plasma (53 UBC, 49 controls) and urine (59 UBC, 57 controls) increased in cases, being statistically significant in urine. MMP23B dosage observed in urine samples was related to both tumor risk classification and grading. As the lack of correlation between mRNA and protein levels could be due to a posttranscriptional regulation mediated by microRNAs (miRNAs), we investigated the expression of urinary miRNAs targeting MMP23B. Five miRNAs resulted differentially expressed between cases and controls. We reported the first evidence of MMP23B secretion in plasma and urine, suggesting a role of this poorly characterized metalloproteinase in UBC as a potential non-invasive biomarker for this cancer. Further analyses are needed to elucidate the mechanism of regulation of MMP23B expression by miRNAs.

Urinary cell-free microRNA biomarker could discriminate bladder cancer from benign hematuria

The most common symptom of bladder cancer (BC) is hematuria. However, not all patients with hematuria are diagnosed with BC. Here, we explored a novel method to discriminate BC from hematuria under nonmalignant conditions by measuring differences in urinary cell-free microRNA (miRNA) expression between patients with BC and those with hematuria. A multicenter study was performed using 543 urine samples obtained from the National Biobank of Korea, including 326 BC, 174 hematuria and 43 pyuria without cancer. The urinary miR-6124 to miR-4511 ratio was considerably higher in BC than in hematuria or pyuria, and enabled the discrimination of BC from patients with hematuria at a sensitivity of >90% (p < 0.001). Conclusively, the proposed noninvasive diagnostic tool based on the expression ratio of urinary cell-free miR-6124 to miR-4511 can reduce unnecessary cystoscopies in patients with hematuria undergoing evaluation for BC, with a minimal loss in sensitivity for detecting cancer.

Liquid Biopsy Biomarkers in Bladder Cancer: A Current Need for Patient Diagnosis and Monitoring

Bladder Cancer (BC) represents a clinical and social challenge due to its high incidence and recurrence rates, as well as the limited advances in effective disease management. Currently, a combination of cytology and cystoscopy is the routinely used methodology for diagnosis, prognosis and disease surveillance. However, both the poor sensitivity of cytology tests as well as the high invasiveness and big variation in tumour stage and grade interpretation using cystoscopy, emphasizes the urgent need for improvements in BC clinical guidance. Liquid biopsy represents a new non-invasive approach that has been extensively studied over the last decade and holds great promise. Even though its clinical use is still compromised, multiple studies have recently focused on the potential application of biomarkers in liquid biopsies for BC, including circulating tumour cells and DNA, RNAs, proteins and peptides, metabolites and extracellular vesicles. In this review, we summarize the present knowledge on the different types of biomarkers, their potential use in liquid biopsy and clinical applications in BC.

Circulating miRNAs in blood and urine as diagnostic and prognostic biomarkers for bladder cancer: an update in 2017

This study presents a critical appraisal of previously published study data of miRNAs in blood, urine and exosomes as biomarkers of bladder cancer (BC). The evaluation included 39 articles published from the beginning of 2010 until September 2017 and searched in PubMed. The heterogeneity of studies, due to their clinicopathological variability, including insufficient consideration of diagnostic and prognostic biomarker guidelines and missing internal and external validation of data, do not currently allow the recommending of a useful miRNA marker as diagnostic or prognostic tool in BC. Future multi-institutional studies are necessary to overcome the deficiencies in these studies in order to prove the usefulness of circulating miRNAs as robust biomarkers for BC.

Cell-free microRNA expression signatures in urine serve as novel noninvasive biomarkers for diagnosis and recurrence prediction of bladder cancer

Urinary microRNAs (miRNAs) are potential biomarkers for the noninvasive diagnosis of bladder cancer (BC). In this study, we aimed to develop a urinary miRNAs panel for diagnosing and predicting recurrence of BC. Genome-wide miRNAs analysis by deep sequencing followed by two phases of quantitative real-time PCR assays were performed on urine supernatant of 276 BC patients and 276 controls. We identified a seven-miRNA panel (miR-7-5p, miR-22-3p, miR-29a-3p, miR-126-5p, miR-200a-3p, miR-375, and miR-423-5p) that provided high diagnostic accuracy of BC with an AUC of 0.923 and 0.916 in training and validation set, respectively. The corresponding AUCs of this panel for Ta, T1 and T2-T4 were 0.864, 0.930 and 0.978, significantly higher than those of urine cytology, which were 0.531, 0.628 and 0.724, respectively (all p < 0.05). Moreover, Kaplan–Meier analysis showed that nonmuscle-invasive BC (NMIBC) patients with high miR-22-3p and low miR-200a-3p level had worse recurrence-free survival (RFS) (p = 0.002 and 0.040, respectively). Multivariate Cox regression analysis revealed that miR-22-3p and miR-200a-3p were independently associated with RFS of NMIBC (p = 0.024 and 0.008, respectively). In conclusion, our results suggested that urinary miRNAs may have considerable clinical value in diagnosis and recurrence prediction of BC.

Urine miRNA as a potential biomarker for bladder cancer detection - a meta-analysis

Introduction

White light cystoscopy (WLC), often supported by urine cytology, is considered the ‘goldstandard’ in the diagnosis and follow-up of bladder cancer (BCa). In recent years, urine microRNA (miRNA) tests have been performed for the detection of bladder cancer.

Material and methods

A systematic review of the PubMed platform was performed by searching for articles in which miRNA in the urine was used for the detection of BCa.

Results

The greatest sensitivity (86.6%) in BCa detection was achieved for multi-miRNA in urine sediment. The greatest specificity (85.3%) was achieved for multi-miRNA from voided urine. There were significant differences (p <0.01) between single-miRNA (OR 8.96; CI 6.37–12.59) and the multi-miRNA group (OR 19.95; CI 13.35–29.81). There were no differences among the specimens (voided urine, supernatant, sediment) used for the test.

Conclusions

Urine miRNAs have the potential to be a valid marker for bladder cancer detection. They can successfully compete with other non-invasive diagnostic tests.

Dysregulation of miRNAs in bladder cancer: altered expression with aberrant biogenesis procedure

Aberrant expression profiles of miRNAs are widely observed in the clinical tissue specimens and urine samples as well as the blood samples of bladder cancer patients. These profiles are closely related to the pathological features of bladder cancer, such as the tumour stage/grade, metastasis, recurrence and chemo-sensitivity. MiRNA biogenesis forms the basis of miRNA expression and function, and its dysregulation has been shown to be essential for variations in miRNA expression profiles as well as tumourigenesis and cancer progression. In this review, we summarize the up-to-date and widely reported miRNAs in bladder cancer that display significantly altered expression. We then compare the miRNA expression profiles among three different sample types (tissue, urine and blood) from patients with bladder cancer. Moreover, for the first time, we outline the dysregulated miRNA biogenesis network in bladder cancer from different levels and analyse its possible relationship with aberrant miRNA expression and the pathological characteristics of the disease.

Diagnostic significance of microRNAs as novel biomarkers for bladder cancer: a meta-analysis of ten articles

BACKGROUND

Previous studies have revealed the importance of microRNAs' (miRNAs) function as biomarkers in diagnosing human bladder cancer (BC). However, the results are discordant. Consequently, the possibility of miRNAs to be BC biomarkers was summarized in this meta-analysis.

METHODS

In this study, the relevant articles were systematically searched from CBM, PubMed, EMBASE, and Chinese National Knowledge Infrastructure (CNKI). The bivariate model was used to calculate the pooled diagnostic parameters and summary receiver operator characteristic (SROC) curve in this meta-analysis, thereby estimating the whole predictive performance. STATA software was used during the whole analysis.

RESULTS

Thirty-one studies from 10 articles, including 1556 cases and 1347 controls, were explored in this meta-analysis. In short, the pooled sensitivity, area under the SROC curve, specificity, positive likelihood ratio, diagnostic odds ratio, and negative likelihood ratio were 0.72 (95%CI 0.66-0.76), 0.80 (0.77-0.84), 0.76 (0.71-0.81), 3.0 (2.4-3.8), 8 (5.0-12.0), and 0.37 (0.30-0.46) respectively. Additionally, sub-group and meta-regression analyses revealed that there were significant differences between ethnicity, miRNA profiling, and specimen sub-groups. These results suggested that Asian population-based studies, multiple-miRNA profiling, and blood-based assays might yield a higher diagnostic accuracy than their counterparts.

CONCLUSIONS

This meta-analysis demonstrated that miRNAs, particularly multiple miRNAs in the blood, might be novel, useful biomarkers with relatively high sensitivity and specificity and can be used for the diagnosis of BC. However, further prospective studies with more samples should be performed for further validation.

Beyond circulating microRNA biomarkers: Urinary microRNAs in ovarian and breast cancer

Breast cancer is the most common malignancy in women worldwide, and ovarian cancer is the most lethal gynecological malignancy. Women carrying a BRCA1/2 mutation have a very high lifetime risk of developing breast and ovarian cancer. The only effective risk-reducing strategy in BRCA-mutated women is a prophylactic surgery with bilateral mastectomy and bilateral salpingo-oophorectomy. However, many women are reluctant to undergo these prophylactic surgeries due to a consequent mutilated body perception, unfulfilled family planning, and precocious menopause. In these patients, an effective screening strategy is available only for breast cancer, but it only consists in close radiological exams with a significant burden for the health system and a significant distress to the patients. No biomarkers have been shown to effectively detect breast and ovarian cancer at an early stage. MicroRNAs (miRNAs) are key regulatory molecules operating in a post-transcriptional regulation of gene expression. Aberrant expression of miRNAs has been documented in several pathological conditions, including solid tumors, suggesting their involvement in tumorigenesis. miRNAs can be detected in blood and urine and could be used as biomarkers in solid tumors. Encouraging results are emerging in gynecological malignancy as well, and suggest a different pattern of expression of miRNAs in biological fluids of breast and ovarian cancer patients as compared to healthy control. Aim of this study is to highlight the role of the urinary miRNAs which are specifically associated with cancer and to investigate their role in early diagnosis and in determining the prognosis in breast and ovarian cancer.

MicroRNAs in biofluids are novel tools for bladder cancer screening

MicroRNAs (miRNAs) are short non-coding RNAs that play important roles in basic cellular processes, including differentiation, proliferation, apoptosis and autophagy. They are also involved in various stages of tumorigenesis and play key roles in bladder cancer initiation and progression. Notably, the altered expression of miRNAs in the tumors is reflected in body fluids, including blood and urine, which opens avenues for non-invasive diagnosis and prognosis. Many studies have demonstrated that epigenetic changes extensively alter tumoral microRNA expression. The high reproducibility, specificity and sensitivity of miRNA levels in body fluids suggest their potential use as biomarkers for cancer screening and diagnosis. For example, recent technological advances have made it possible to detect miRNAs in urine for bladder cancer screening. In this review, we focus mainly on the current knowledge and future challenges for incorporating miRNAs in body fluids, like urine and blood, for making clinical diagnoses and assessing prognoses in bladder cancer.

MicroRNAs as noninvasive biomarkers in bladder cancer detection: a diagnostic meta-analysis based on qRT-PCR data

OBJECTIVE

As the diagnostic significance of microRNAs (miRNAs) in the detection of bladder cancer is controversial, we aimed to perform a meta-analysis to comprehensively assess the diagnostic value of miRNAs in blood and urine for detecting bladder cancer.

METHODS

A systematic literature search of public databases was conducted to obtain qualified studies. Sensitivity was utilized to plot the summary receiver operator characteristic (SROC) curve against specificity and the area under the SROC curve (AUC) was generated to evaluate the pooled diagnostic efficiency. Subgroup analyses and meta-regression were applied to investigate the underlying sources of heterogeneity. The STATA 12.0 software was used to perform all statistic analyses.

RESULTS

A total of 58 studies from 22 articles comprising 4,558 bladder cancer patients and 4,456 controls were included in our meta-analysis. MiRNAs in blood and urine manifested relatively good diagnostic efficiency in detecting bladder cancer, with a sensitivity of 0.74, a specificity of 0.78, and an AUC of 0.83. Multiple-miRNA assays were more accurate than single-miRNA ones in bladder cancer diagnosis. Blood-based miRNA assays displayed better diagnostic performance than urine-based ones. In addition, miRNAs showed reduced diagnostic value in bladder cancer among Caucasians compared with Asians.

CONCLUSIONS

MiRNAs in blood and urine, especially the combination of multiple miRNAs, may serve as hopeful noninvasive biomarkers for early diagnosis of bladder cancer. Further extensive prospective research is needed to verify their clinical significance in bladder cancer diagnosis.

Clinical relevance of circulating cell-free microRNAs in ovarian cancer

Ovarian cancer is the leading cause of death among gynecologic malignancies. Since ovarian cancer develops asymptomatically, it is often diagnosed at an advanced and incurable stage. Despite many years of research, there is still a lack of reliable diagnostic markers and methods for early detection and screening. Recently, it was discovered that cell-free microRNAs (miRNAs) circulate in the body fluids of healthy and diseased patients, suggesting that they may serve as a novel diagnostic marker. This review summarizes the current knowledge regarding the potential clinical relevance of circulating cell-free miRNA for ovarian cancer diagnosis, prognosis, and therapeutics. Despite the high levels of ribonucleases in many types of body fluids, most of the circulating miRNAs are packaged in microvesicles, exosomes, or apoptotic bodies, are binding to RNA-binding protein such as argonaute 2 or lipoprotein complexes, and are thus highly stable. Cell-free miRNA signatures are known to be parallel to those from the originating tumor cells, indicating that circulating miRNA profiles accurately reflect the tumor profiles. Since it is well established that the dysregulation of miRNAs is involved in the tumorigenesis of ovarian cancer, cell-free miRNAs circulating in body fluids such as serum, plasma, whole blood, and urine may reflect not only the existence of ovarian cancer but also tumor histology, stage, and prognoses of the patients. Several groups have successfully demonstrated that serum or plasma miRNAs are able to discriminate patients with ovarian cancer patients from healthy controls, suggesting that the addition of these miRNAs to current testing regimens may improve diagnosis accuracies for ovarian cancer. Furthermore, recent studies have revealed that changes in levels of cell-free circulating miRNAs are associated with the condition of cancer patients. Discrepancies between the results across studies due to the lack of an established endogenous miRNA control to normalize for circulating miRNA levels, as well as differing extraction and quantification methods, are the pitfalls to be resolved before clinical application. There is still a long way, however, before this can be achieved, and further evidence would make it possible to apply circulating cell-free miRNAs not only as biomarkers but also as potential therapeutic targets for ovarian cancer in the future.

The role of microRNAs in bladder cancer

Bladder cancer (BC) is the fifth most common cancer worldwide and is associated with significant morbidity and mortality. The prognosis of muscle invasive BC is poor, and recurrence is common after radical surgery or chemotherapy. Therefore, new diagnostic methods and treatment modalities are critical. MicroRNAs (miRNAs), a class of small noncoding RNAs, regulate the expression of protein-coding genes by repressing translation or cleaving RNA transcripts in a sequence-specific manner. miRNAs have important roles in the regulation of genes involved in cancer development, progression, and metastasis. The availability of genomewide miRNA expression profiles by deep sequencing technology has facilitated rapid and precise identification of aberrant miRNA expression in BC. Indeed, several miRNAs that are either upregulated or downregulated have been shown to have associations with significant cancer pathways. Furthermore, many miRNAs, including those that can be detected in urine and blood, have been studied as potential noninvasive tumor markers for diagnostic and prognostic purposes. Here, we searched PubMed for publications describing the role of miRNAs in BC by using the keywords "bladder cancer" and "microRNA" on March 1, 2016. We found 374 papers and selected articles written in English in which the level of scientific detail and reporting were sufficient and in which novel findings were demonstrated. In this review, we summarize these studies from the point of view of miRNA-related molecular networks (specific miRNAs and their targets) and miRNAs as tumor markers in BC. We also discuss future directions of miRNA studies in the context of therapeutic modalities.

Predicting MicroRNA Biomarkers for Cancer Using Phylogenetic Tree and Microarray Analysis

MicroRNAs (miRNAs) are shown to be involved in the initiation and progression of cancers in the literature, and the expression of miRNAs is used as an important cancer prognostic tool. The aim of this study is to predict high-confidence miRNA biomarkers for cancer. We adopt a method that combines miRNA phylogenetic structure and miRNA microarray data analysis to discover high-confidence miRNA biomarkers for colon, prostate, pancreatic, lung, breast, bladder and kidney cancers. There are 53 miRNAs selected through this method that either have potential to involve a single cancer's development or to involve several cancers' development. These miRNAs can be used as high-confidence miRNA biomarkers of these seven investigated cancers for further experiment validation. miR-17, miR-20, miR-106a, miR-106b, miR-92, miR-25, miR-16, miR-195 and miR-143 are selected to involve a single cancer's development in these seven cancers. They have the potential to be useful miRNA biomarkers when the result can be confirmed by experiments.

New Concepts in Cancer Biomarkers: Circulating miRNAs in Liquid Biopsies

The effective and efficient management of cancer patients relies upon early diagnosis and/or the monitoring of treatment, something that is often difficult to achieve using standard tissue biopsy techniques. Biological fluids such as blood hold great possibilities as a source of non-invasive cancer biomarkers that can act as surrogate markers to biopsy-based sampling. The non-invasive nature of these “liquid biopsies” ultimately means that cancer detection may be earlier and that the ability to monitor disease progression and/or treatment response represents a paradigm shift in the treatment of cancer patients. Below, we review one of the most promising classes of circulating cancer biomarkers: microRNAs (miRNAs). In particular, we will consider their history, the controversy surrounding their origin and biology, and, most importantly, the hurdles that remain to be overcome if they are really to become part of future clinical practice.

Expression Level of Urinary MicroRNA-146a-5p Is Increased in Patients With Bladder Cancer and Decreased in Those After Transurethral Resection

BACKGROUND

Bladder cancer is the most prevalent malignancy involving the urinary system and exhibits a markedly high recurrence rate. Therefore, reliable and noninvasive diagnostic and surveillance methods are desperately needed.

PATIENTS AND METHODS

Candidate microRNAs (miRNAs) were selected from the miRNAs that were differentially expressed in bladder cancer cell lines (T24 and RT4) compared to normal ureteral epithelial tissue using miRNA-microarray analysis. The candidate miRNAs were validated by quantitative reverse transcription polymerase chain reaction assay using voided urine samples.

RESULTS

We identified 3 miRNAs (miR-301b, -563, and -146a-5p) that demonstrated > 2-fold higher expression levels in cancer cell lines than in the normal ureteral epithelial tissue. Of these, only miR-146a-5p was consistently and significantly higher in urine samples from the patients with bladder cancer than in those from the normal individuals (P = .0014). The patients with high-grade tumors exhibited significantly higher urinary miR-146a-5p levels than those with low-grade tumors, and the patients with invasive tumors tended to show higher urinary miR-146a-5p levels than those with noninvasive tumors. Elevated urinary miR-146a-5p levels in patients with bladder cancer were decreased to the normal level after transurethral resection of the tumors (P = .0214).

CONCLUSION

Our study suggested that urinary miR-146a-5p might be useful as a new noninvasive diagnostic marker, therapeutic target, or anticancer agent for bladder cancer, as well as for increasing our understanding of cancer biology.

Circulating microRNAs and long non-coding RNAs in gastric cancer diagnosis: An update and review

Gastric cancer (GC) is the fourth most common cancer and the third leading cause of cancer mortality worldwide. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are the most popular non-coding RNAs in cancer research. To date, the roles of miRNAs and lncRNAs have been extensively studied in GC, suggesting that miRNAs and lncRNAs represent a vital component of tumor biology. Furthermore, circulating miRNAs and lncRNAs are found to be dysregulated in patients with GC compared with healthy individuals. Circulating miRNAs and lncRNAs may function as promising biomarkers to improve the early detection of GC. Multiple possibilities for miRNA secretion have been elucidated, including active secretion by microvesicles, exosomes, apoptotic bodies, high-density lipoproteins and protein complexes as well as passive leakage from cells. However, the mechanism underlying lncRNA secretion and the functions of circulating miRNAs and lncRNAs have not been fully illuminated. Concurrently, to standardize results of global investigations of circulating miRNAs and lncRNAs biomarker studies, several recommendations for pre-analytic considerations are put forward. In this review, we summarize the known circulating miRNAs and lncRNAs for GC diagnosis. The possible mechanism of miRNA and lncRNA secretion as well as methodologies for identification of circulating miRNAs and lncRNAs are also discussed. The topics covered here highlight new insights into GC diagnosis and screening.

Regulation of growth of human bladder cancer by miR-192

The regulation of microRNA-192 (miR-192) is impaired in many cancers. Here, we investigated the role of miR-192 in the proliferation, cell cycle progression, and apoptosis of bladder cancer cells. Human bladder cancer cells were transfected with human miR-192 precursor or non-specific control miRNA. The effect of miR-192 on cell proliferation was assessed by a MTT assay. The effects of miR-192 on cell cycle regulation and apoptosis were evaluated by flow cytometry. Western blot was used to analyze the protein levels of cyclin D1, p21, p27, Bcl-2, Bax, and Mcl-1. We found that overexpression of miR-192 significantly decreased the proliferation of bladder cancer cells by 22 and 54 % at 48 and 72 h, respectively. MiR-192-overexpressing cells exhibited a significant increase in G0/G1 phase and a significant decrease in S phase compared to the control miRNA-transfected cells. Moreover, overexpression of miR-192 significantly induced apoptotic death in bladder cancer cells, increased the levels of p21, p27, and Bax, and decreased the levels of cyclin D1, Bcl-2, and Mcl-1. Taken together, these data suggest that miR-192 may be a suppressor for bladder cancer cells by cell cycle regulation.

Diagnostic Relevance of microRNAs in Other Body Fluids Including Urine, Feces, and Saliva

Beside blood-borne circulating miRNAs, miRNAs have been identified in other body fluid and excrements including stool, bile, saliva, and urine. Given the direct link of these body fluids to certain organs, their analysis for potential diagnostic miRNA markers is plausible. Several independent findings underline the potential utility of stool-derived miRNAs in the diagnosis of colorectal and pancreatic cancer. Given the difficulties in the diagnosis of cholangiocellular cancer, biliary miRNAs might be envisaged as useful markers. Several miRNAs have been identified in the saliva that could be associated with diseases, including tumors of the oral cavity. The urinary pool of miRNAs could be exploited for the diagnosis of urinary tract diseases and some appear to enable early diagnosis. In this chapter, we present findings supporting the potential diagnostic utility of fecal, biliary, salivary, and urinary miRNAs focusing mostly on tumors.