MicroRNA-21 in Pancreatic Ductal Adenocarcinoma Tumor-Associated Fibroblasts Promotes Metastasis

Introduction

Pancreatic ductal adenocarcinoma (PDAC) is projected to rise to the second leading cause of U.S. cancer-related deaths by 2020. Novel therapeutic targets are desperately needed. MicroRNAs (miRs) are small noncoding RNAs that function by suppressing gene expression and are dysregulated in cancer. miR-21 is overexpressed in PDAC tumor cells (TC) and is associated with decreased survival, chemoresistance and invasion. Dysregulation of miR regulatory networks in PDAC tumor-associated fibroblasts (TAFs) have not been previously described. In this study, we show that miR-21 expression in TAFs promotes TC invasion.

Methods

In-situ hybridization for miR-21 was performed on the 153 PDAC patient UCLA tissue microarray and 23 patient-matched lymph node metastases. Stromal and TC histoscores were correlated with clinicopathologic parameters by univariate and multivariate Cox regression. miR-21 positive cells were further characterized by immunofluorescence for mesenchymal/epithelial markers. For in vitro studies, TAFs were isolated from freshly resected human PDAC tumors by the outgrowth method. miR-21 was overexpressed/inhibited in fibroblasts and then co-cultured with GFP-MiaPaCa TCs to assess TC invasion in modified Boyden chambers.

Results

miR-21 was upregulated in TAFs of 78% of tumors, and high miR-21 significantly correlated with decreased overall survival (P = 0.04). Stromal miR-21 expression was also significantly associated with lymph node invasion (P = 0.004), suggesting that it is driving TC spread. Co-immunofluorescence revealed that miR-21 colocalized with peritumoral fibroblasts expressing α-smooth muscle actin. Moreover, expression of miR-21 in primary TAFs correlated with miR-21 in TAFs from patient-matched LN metastases; evidence that PDAC tumor cells induce TAFs to express miR-21. miR-21 expression in TAFs and TCs promotes invasion of TCs and is inhibited with anti-miR-21.

Conclusions

miR-21 expression in PDAC TAFs is associated with decreased overall survival and promotes TC invasion. Anti-miR-21 may represent a novel therapeutic strategy for dual targeting of both tumor and stroma in PDAC.     

Finasteride Inhibits Human Prostate Cancer Cell Invasion through MMP2 and MMP9 Downregulation

Introduction

The use of the 5-alpha reductase inhibitors (5-ARIs) finasteride and dutasteride for prostate cancer prevention is still under debate. The FDA recently concluded that the increased prevalence of high-grade tumors among 5-ARI-treated patients must not be neglected, and they decided to disallow the use of 5-ARIs for prostate cancer prevention. This study was conducted to verify the effects of finasteride on prostate cell migration and invasion and the related enzymes/proteins in normal human and tumoral prostatic cell lines.

Materials and Methods

RWPE-1, LNCaP, PC3 and DU145 cells were cultivated to 60% confluence and exposed for different periods to either 10 µM or 50 µM finasteride that was diluted in culture medium. The conditioned media were collected and concentrated, and MMP2 and MMP9 activities and TIMP-1 and TIMP-2 protein expression were determined. Cell viability, migration and invasion were analyzed, and the remaining cell extracts were submitted to androgen receptor (AR) detection by western blotting techniques. Experiments were carried out in triplicate.

Results

Cell viability was not significantly affected by finasteride exposure. Finasteride significantly downregulated MMP2 and MMP9 activities in RWPE-1 and PC3 cells and MMP2 in DU145 cells. TIMP-2 expression in RWPE-1 cells was upregulated after exposure. The cell invasion of all four tested cell lines was inhibited by exposure to 50 µM of finasteride, and migration inhibition only occurred for RWPE-1 and LNCaP cells. AR was expressed by LNCaP, RWPE-1 and PC3 cells.

Conclusions

Although the debate on the higher incidence of high-grade prostate cancer among 5-ARI-treated patients remains, our findings indicate that finasteride may attenuate tumor aggressiveness and invasion, which could vary depending on the androgen responsiveness of a patient’s prostate cells.     

The Expression of TMPRSS4 and Erk1 Correlates with Metastasis and Poor Prognosis in Chinese Patients with Gastric Cancer

Purpose

The present study investigated the clinical significance of transmembrane protease, serine 4(TMPRSS4) and extracellular signal-regulated kinases 1 (Erk1) in the development, progression and metastasis of gastric cancer.

Methods

Immunohistochemistry was employed to analyze TMPRSS4 and Erk1 expression in 436 gastric cancer cases and 92 non-cancerous human gastric tissues.

Results

Protein levels of TMPRSS4 and Erk1 were up-regulated in gastric cancer lesions compared with adjacent noncancerous tissues. High expression of TMPRSS4 correlated with age, size, Lauren’s classification, depth of invasion, lymph node and distant metastases, regional lymph node stage and TNM stage, and also with expression of Erk1. In stages I, II and III, the 5-year survival rate of patients with high TMPRSS4 expression was significantly lower than in patients with low expression. Further multivariate analysis suggests that up-regulation of TMPRSS4 and Erk1 were independent prognostic indicators for the disease, along with depth of invasion, lymph node and distant metastasis and TNM stage.

Conclusions

Expression of TMPRSS4 in gastric cancer is significantly associated with lymph node and distant metastasis, high Erk1 expression, and poor prognosis. TMPRSS4 and Erk1 proteins could be useful markers to predict tumor progression and prognosis of gastric cancer.     

Matrix metalloproteinase gene polymorphisms and bronchopulmonary dysplasia: identification of MMP16 as a new player in lung development

Backgound

Alveolarization requires coordinated extracellular matrix remodeling, a process in which matrix metalloproteinases (MMPs) play an important role. We postulated that polymorphisms in MMP genes might affect MMP function in preterm lungs and thus influence the risk of bronchopulmonary dysplasia (BPD).

Methods and Findings

Two hundred and eighty-four consecutive neonates with a gestational age of <28 weeks were included in this prospective study. Forty-five neonates developed BPD. Nine single-nucleotide polymorphisms (SNPs) were sought in the MMP2, MMP14 and MMP16 genes. After adjustment for birth weight and ethnic origin, the TT genotype of MMP16 C/T (rs2664352) and the GG genotype of MMP16 A/G (rs2664349) were found to protect from BPD. These genotypes were also associated with a smaller active fraction of MMP2 and with a 3-fold-lower MMP16 protein level in tracheal aspirates collected within 3 days after birth. Further evaluation of MMP16 expression during the course of normal human and rat lung development showed relatively low expression during the canalicular and saccular stages and a clear increase in both mRNA and protein levels during the alveolar stage. In two newborn rat models of arrested alveolarization the lung MMP16 mRNA level was less than 50% of normal.

Conclusions

MMP16 may be involved in the development of lung alveoli. MMP16 polymorphisms appear to influence not only the pulmonary expression and function of MMP16 but also the risk of BPD in premature infants.     

Meta-Analysis of MMP2, MMP3, and MMP9 Promoter Polymorphisms and Head and Neck Cancer Risk

Background

The 1306 C>T, 1171 5A>6A, and 1562C>T polymorphisms of matrix metalloproteinase (MMP) 2, MMP3, and MMP9 genes, respectively, have been found to be functional and may contribute to head and neck carcinogenesis. However, the results of case-control studies examining associations between MMP polymorphisms and head and neck cancer (HNC) risk remain inconclusive. Therefore, we performed a meta-analysis to further evaluate the role of these polymorphisms in HNC development.

Methods

We searched PubMed, ISI Web of Knowledge, MEDLINE, Embase, and Google Scholar to identify all published case-control studies of MMP2-1306 C>T, MMP3-1171 5A>6A, and MMP9-1562 C>T polymorphisms and HNC risk in the meta-analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the association between these polymorphisms and HNC risk.

Results

Thirteen studies were included in this meta-analysis. For MMP2-1306 C>T polymorphism, significant associations were observed under three genetic models both in overall comparison and in a hospital-based subgroup, and in oral cavity cancer and nasopharyngeal cancer under dominant model as well. For MMP3-1171 5A>6A and MMP9-1562 C>T polymorphisms, no association was found in overall comparison; however, in subgroup analyses based on ethnicity and tumor site, significant associations were detected between the MMP3-1171 5A>6A polymorphism and HNC risk in a European population and pharyngeal/laryngeal cancer under two genetic contrasts.

Conclusion

This meta-analysis suggests that the MMP2-1306 C>T polymorphism is associated with HNC risk, as is the MMP3-1171 5A>6A polymorphism specifically in some subgroups. Further studies with larger sample sizes are warranted.     

FOXP3+ Lymphocyte Density in Pancreatic Cancer Correlates with Lymph Node Metastasis

Objective

To determine if the density of FOXP3⁺ lymphocytes in primary tumors and lymph nodes in pancreatic cancer correlates with the presence of lymph node metastases.

Methods

FOXP3⁺ lymphocyte density in primary pancreatic cancer tissue and draining lymph nodes was measured using immunohistochemistry. We analyzed the clinical and pathological aspects associated with the accumulation of FOXP3⁺ lymphocytes in pancreatic cancer. We also analyzed the correlation of density of FOXP3⁺ lymphocytes in lymph nodes with the nodal status and distance from the primary tumor.

Results

FOXP3⁺ lymphocyte density in pancreatic cancer was significantly higher than in paratumoral pancreatic tissue. The density of FOXP3⁺ lymphocytes in local tumor tissue correlated significantly with the histological grade and overall lymph node status. Furthermore, FOXP3⁺ lymphocyte density was significantly higher in positive lymph nodes than in negative ones, while it had no correlation with the distance of the lymph node from the primary tumor.

Conclusion

FOXP3⁺ lymphocyte density in primary tumor tissue in patients with pancreatic cancer correlates with lymph node metastasis. Lymph nodes containing metastases having higher FOXP3⁺ lymphocyte densities than do negative lymph nodes.     

Contributions of Ocular Surface Components to Matrix-Metalloproteinases (MMP)-2 and MMP-9 in Feline Tears following Corneal Epithelial Wounding

Purpose

This study investigated ocular surface components that contribute to matrix-metalloproteinase (MMP)-2 and MMP-9 found in tears following corneal epithelial wounding.

Methods

Laboratory short-haired cats underwent corneal epithelial debridement in one randomly chosen eye (n = 18). Eye-flush tears were collected at baseline and during various healing stages. Procedural control eyes (identical experimental protocol as wounded eyes except for wounding, n = 5) served as controls for tear analysis. MMP activity was analyzed in tears using gelatin zymography. MMP staining patterns were evaluated in ocular tissues using immunohistochemistry and used to determine MMP expression sites responsible for tear-derived MMPs.

Results

The proMMP-2 and proMMP-9 activity in tears was highest in wounded and procedural control eyes during epithelial migration (8 to 36 hours post-wounding). Wounded eyes showed significantly higher proMMP-9 in tears only during and after epithelial restratification (day 3 to 4 and day 7 to 28 post-wounding, respectively) as compared to procedural controls (p<0.05). Tears from wounded and procedural control eyes showed no statistical differences for pro-MMP-2 and MMP-9 (p>0.05). Immunohistochemistry showed increased MMP-2 and MMP-9 expression in the cornea during epithelial migration and wound closure. The conjunctival epithelium exhibited highest levels of both MMPs during wound closure, while MMP-9 expression was reduced in conjunctival goblet cells during corneal epithelial migration followed by complete absence of the cells during wound closure. The immunostaining for both MMPs was elevated in the lacrimal gland during corneal healing, with little/no change in the meibomian glands. Conjunctival-associated lymphoid tissue (CALT) showed weak MMP-2 and intense MMP-9 staining.

Conclusions

Following wounding, migrating corneal epithelium contributed little to the observed MMP levels in tears. The major sources assessed in the present study for tear-derived MMP-2 and MMP-9 following corneal wounding are the lacrimal gland and CALT. Other sources included stromal keratocytes and conjunctiva with goblet cells.     

Mir-34a is upregulated during liver regeneration in rats and is associated with the suppression of hepatocyte proliferation

Background

MicroRNAs are a class of small regulatory RNAs that modulate a variety of biological processes, including cellular differentiation, apoptosis, metabolism and proliferation. This study aims to explore the effect of miR-34a in hepatocyte proliferation and its potential role in liver regeneration termination.

Methodology/Principal Finding

MiR-34a was highly induced after partial hepatectomy. Overexpression of miR-34a in BRL-3A cells could significantly inhibit cell proliferation and down-regulate the expression of inhibin βB (INHBB) and Met. In BRL-3A cells, INHBB was identified as a direct target of miR-34a by luciferase reporter assay. More importantly, INHBB siRNA significantly repressed cell proliferation. A decrease of INHBB and Met was detected in regenerating liver.

Conclusion/Significance

MiR-34a expression was upregulated during the late phase of liver regeneration. MiR-34a-mediated regulation of INHBB and Met may collectively contribute to the suppression of hepatocyte proliferation.     

Validation of Expression Patterns for Nine miRNAs in 204 Lymph-Node Negative Breast Cancers

Introduction

Although lymph node negative (LN-) breast cancer patients have a good 10-years survival (∼85%), most of them still receive adjuvant therapy, while only some benefit from this. More accurate prognostication of LN- breast cancer patient may reduce over- and under-treatment. Until now proliferation is the strongest prognostic factor for LN- breast cancer patients. The small molecule microRNA (miRNA) has opened a new window for prognostic markers, therapeutic targets and/or therapeutic components. Previously it has been shown that miR-18a/b, miR-25, miR-29c and miR-106b correlate to high proliferation.

Methods

The current study validates nine miRNAs (miR-18a/b miR-25, miR-29c, miR-106b, miR375, miR-424, miR-505 and let-7b) significantly correlated with established prognostic breast cancer biomarkers. Total RNA was isolated from 204 formaldehyde-fixed paraffin embedded (FFPE) LN- breast cancers and analyzed with quantitative real-time Polymerase Chain Reaction (qPCR). Independent T-test was used to detect significant correlation between miRNA expression level and the different clinicopathological features for breast cancer.

Results

Strong and significant associations were observed for high expression of miR-18a/b, miR-106b, miR-25 and miR-505 to high proliferation, oestrogen receptor negativity and cytokeratin 5/6 positivity. High expression of let-7b, miR-29c and miR-375 was detected in more differentiated tumours. Kaplan-Meier survival analysis showed that patients with high miR-106b expression had an 81% survival rate vs. 95% (P = 0.004) for patients with low expression.

Conclusion

High expression of miR-18a/b are strongly associated with basal-like breast cancer features, while miR-106b can identify a group with higher risk for developing distant metastases in the subgroup of Her2 negatives. Furthermore miR-106b can identify a group of patients with 100% survival within the otherwise considered high risk group of patients with high proliferation. Using miR-106b as a biomarker in conjunction to mitotic activity index could thereby possibly save 18% of the patients with high proliferation from overtreatment.     

PRC2/EED-EZH2 Complex Is Up-Regulated in Breast Cancer Lymph Node Metastasis Compared to Primary Tumor and Correlates with Tumor Proliferation In Situ

Background

Lymph node metastasis is a key event in the progression of breast cancer. Therefore it is important to understand the underlying mechanisms which facilitate regional lymph node metastatic progression.

Methodology/Principal Findings

We performed gene expression profiling of purified tumor cells from human breast tumor and lymph node metastasis. By microarray network analysis, we found an increased expression of polycomb repression complex 2 (PRC2) core subunits EED and EZH2 in lymph node metastatic tumor cells over primary tumor cells which were validated through real-time PCR. Additionally, immunohistochemical (IHC) staining and quantitative image analysis of whole tissue sections showed a significant increase of EZH2 expressing tumor cells in lymph nodes over paired primary breast tumors, which strongly correlated with tumor cell proliferation in situ. We further explored the mechanisms of PRC2 gene up-regulation in metastatic tumor cells and found up-regulation of E2F genes, MYC targets and down-regulation of tumor suppressor gene E-cadherin targets in lymph node metastasis through GSEA analyses. Using IHC, the expression of potential EZH2 target, E-cadherin was examined in paired primary/lymph node samples and was found to be significantly decreased in lymph node metastases over paired primary tumors.

Conclusions/Significance

This study identified an over expression of the epigenetic silencing complex PRC2/EED-EZH2 in breast cancer lymph node metastasis as compared to primary tumor and its positive association with tumor cell proliferation in situ. Concurrently, PRC2 target protein E-cadherin was significant decreased in lymph node metastases, suggesting PRC2 promotes epithelial mesenchymal transition (EMT) in lymph node metastatic process through repression of E-cadherin. These results indicate that epigenetic regulation mediated by PRC2 proteins may provide additional advantage for the outgrowth of metastatic tumor cells in lymph nodes. This opens up epigenetic drug development possibilities for the treatment and prevention of lymph node metastasis in breast cancer.     

High Prevalence of Human Cytomegalovirus Proteins and Nucleic Acids in Primary Breast Cancer and Metastatic Sentinel Lymph Nodes

Background

Breast cancer is a leading cause of death among women worldwide. Increasing evidence implies that human cytomegalovirus (HCMV) infection is associated with several malignancies. We aimed to examine whether HCMV is present in breast cancer and sentinel lymph node (SLN) metastases.

Materials and Methods

Formalin-fixed paraffin-embedded tissue specimens from breast cancer and paired sentinel lymph node (SLN) samples were obtained from patients with (n = 35) and without SLN metastasis (n = 38). HCMV immediate early (IE) and late (LA) proteins were detected using a sensitive immunohistochemistry (IHC) technique and HCMV DNA by real-time PCR.

Results

HCMV IE and LA proteins were abundantly expressed in 100% of breast cancer specimens. In SLN specimens, 94% of samples with metastases (n = 34) were positive for HCMV IE and LA proteins, mostly confined to neoplastic cells while some inflammatory cells were HCMV positive in 60% of lymph nodes without metastases (n = 35). The presence of HCMV DNA was confirmed in 12/12 (100%) of breast cancer and 10/11 (91%) SLN specimens from the metastatic group, but was not detected in 5/5 HCMV-negative, SLN-negative specimens. There was no statistically significant association between HCMV infection grades and progesterone receptor, estrogen receptor alpha and Elston grade status.

Conclusions

The role of HCMV in the pathogenesis of breast cancer is unclear. As HCMV proteins were mainly confined to neoplastic cells in primary breast cancer and SLN samples, our observations raise the question whether HCMV contributes to the tumorigenesis of breast cancer and its metastases.     

STAT3 Regulates MMP3 in Heme-Induced Endothelial Cell Apoptosis

Background

We have previously reported that free Heme generated during experimental cerebral malaria (ECM) in mice, is central to the pathogenesis of fatal ECM. Heme-induced up-regulation of STAT3 and CXCL10 promotes whereas up-regulation of HO-1 prevents brain tissue damage in ECM. We have previously demonstrated that Heme is involved in the induction of apoptosis in vascular endothelial cells. In the present study, we further tested the hypothesis that Heme reduces blood-brain barrier integrity during ECM by induction of apoptosis of brain vascular endothelial cells through STAT3 and its target gene matrix metalloproteinase three (MMP3) signaling.

Methods

Genes associated with the JAK/STAT3 signaling pathway induced upon stimulation by Heme treatment, were assessed using real time RT² Profile PCR arrays. A human MMP3 promoter was cloned into a luciferase reporter plasmid, pMMP3, and its activity was examined following exposure to Heme treatment by a luciferase reporter gene assay. In order to determine whether activated nuclear protein STAT3 binds to the MMP3 promoter and regulates MMP3 gene, we conducted a ChIP analysis using Heme-treated and untreated human brain microvascular endothelial cells (HBVEC), and determined mRNA and protein expression levels of MMP3 using qRT-PCR and Western blot. Apoptosis in HBVEC treated with Heme was evaluated by MTT and TUNEL assay.

Results

The results show that (1) Heme activates a variety of JAK/STAT3 downstream pathways in HBVEC. STAT3 targeted genes such as MMP3 and C/EBPb (Apoptosis-related genes), are up regulated in HBVEC treated with Heme. (2) Heme-induced HBVEC apoptosis via activation of STAT3 as well as its downstream signaling molecule MMP3 and upregulation of CXCL10 and HO-1 expressions. (3) Phosphorylated STAT3 binds to the MMP3 promoter in HBVEC cells, STAT3 transcribed MMP3 and induced MMP3 protein expression in HBVEC cells.

Conclusions

Activated STAT3 binds to the MMP3 promoter region and regulates MMP3 in Heme-induced endothelial cell apoptosis.     

MMP/TIMP expression profiles in distinct lung disease models: implications for possible future therapies

Background

There is currently a vast amount of evidence in the literature suggesting that matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are involved in the pathogenesis of inflammatory airways diseases, such as asthma and COPD. Despite this, the majority of reports only focus on single MMPs, often only in one model system. This study aimed to investigate the profile of an extensive range of MMP/TIMP levels in three different pre-clinical models of airways disease. These models each have a different and very distinct inflammatory profile, each exhibiting inflammatory characteristics that are similar to that observed in asthma or COPD. Since these models have their own characteristic pathophysiological phenotype, one would speculate that the MMP/TIMP expression profile would also be different.

Methods

With the use of designed and purchased MMP/TIMP assays, investigation of rat MMP-2, 3, 7-14 and TIMP-1-4 mRNA expression was undertaken by Real Time PCR. The three rodent models of airways disease investigated were the endotoxin model, elastase model, and the antigen model.

Results

Intriguingly, we demonstrated that despite the distinct inflammatory profile observed by each model, the MMP/TIMP expression profile is similar between the models, in that the same MMPs/TIMPs were observed to be generally increased or decreased in all three models. It could therefore be speculated that in a particular disease, it may be a complex network of MMPs, rather than an individual MMP, together with inflammatory cytokines and other mediators, that results in the distinct phenotype of inflammatory diseases, such as asthma and COPD.

Conclusion

We believe our data may provide key information necessary to understand the role of various MMPs/TIMPs in different inflammatory airway diseases, and aid the development of more selective therapeutics without the side effect profile of current broad-spectrum MMP inhibitors.     

Stromal Derived Factor-1 (SDF-1) and Its Receptors CXCR4 and CXCR7 in Endometrial Cancer Patients

Purpose

One of the most important function of stromal derived factor-1 (SDF-1) and its receptors, is regulating the process of metastasis formation. The aim of our study was to investigate the correlation between SDF-1, CXCR4 and CXCR7 protein levels measured by immunohistochemistry with the clinicopathological features and the survival of endometrial cancer patients.

Materials and Methods

92 patients aged 37–84 (mean 65.1±9.5) were enrolled to our study between January 2000 and December 2007. After the diagnosis of endometrial cancer, all women underwent total abdominal hysterectomy, with bilateral salpingoophorectomy and pelvic lymph node dissection. In all patients clinical stage (according to FIGO classification), histologic grade, myometrial invasion, lymph node and distant metastases were determined.Furthermore, the survival time was assessed. Immunohistochemical analyses of SDF-1, CXCR4 and CXCR7 were performed on archive formalin fixed paraffin embedded tissue sections.

Results

Statistically significant correlations (p<0.01) were reported between SDF-1 and the clinical stage of disease, lymph node metastases, distant metastases, deep myometrial invasion (≥50%), cervical involvement, involvement of adnexa. Statistically significant correlation (p<0.01) was found between SDF-1 expression and the risk of the recurrence. Higher SDF-1 expression was associated with ahigher risk of recurrence (p = 0.0001). The results of CXCR4and CXCR7 expression didn''t reveal any significant differences(p>0.05) between the proteins expression in the primary tumor cells and the clinicopathological features. Moreover, the Kaplan-Meier analyses demonstrated a stepwise impairment of cancer overall survival (OS) with increasing SDF-1 expression.

Conclusion

The important role of SDF-1 as a predictor of negative clinicopathological characteristics of atumor suggests that the expression of this stromal factor should be included in the panel of accessory pathomorphological tests and could be helpful in establishing a more accurate prognosis in endometrial cancer patients.     

Identification of microRNAs as potential prognostic markers in ependymoma

Introduction

We have examined expression of microRNAs (miRNAs) in ependymomas to identify molecular markers of value for clinical management. miRNAs are non-coding RNAs that can block mRNA translation and affect mRNA stability. Changes in the expression of miRNAs have been correlated with many human cancers.

Materials and Methods

We have utilized TaqMan Low Density Arrays to evaluate the expression of 365 miRNAs in ependymomas and normal brain tissue. We first demonstrated the similarity of expression profiles of paired frozen tissue (FT) and paraffin-embedded specimens (FFPE). We compared the miRNA expression profiles of 34 FFPE ependymoma samples with 8 microdissected normal brain tissue specimens enriched for ependymal cells. miRNA expression profiles were then correlated with tumor location, histology and other clinicopathological features.

Results

We have identified miRNAs that are over-expressed in ependymomas, such as miR-135a and miR-17-5p, and down-regulated, such as miR-383 and miR-485-5p. We have also uncovered associations between expression of specific miRNAs which portend a worse prognosis. For example, we have identified a cluster of miRNAs on human chromosome 14q32 that is associated with time to relapse. We also found that miR-203 is an independent marker for relapse compared to the parameters that are currently used. Additionally, we have identified three miRNAs (let-7d, miR-596 and miR-367) that strongly correlate to overall survival.

Conclusion

We have identified miRNAs that are differentially expressed in ependymomas compared with normal ependymal tissue. We have also uncovered significant associations of miRNAs with clinical behavior. This is the first report of clinically relevant miRNAs in ependymomas.