Malignant myoepithelioma of the external auditory canal - a rare case report with literature review and clinical importance of foramen of Huschke.

BACKGROUND: A malignant myoepithelioma is a rare tumor, mostly arising from the salivary glands. Myoepitheliomas of the ear have rarely been reported. The manuscript reports myoepithelial carcinoma of the external auditory canal (EAC) spreading to the infratemporal fossa. A clinician must be aware of anatomical variation of the bony EAC wall, such as the foramen of Huschke. This rare defect may be a pathway for spreading pathologies between these two anatomical regions. CASE REPORT: We present a case of osteoma-like stenosis of the EAC, which turned out to be an extremely rare malignant tumor. The preoperative MRI and PET/CT revealed that two parts of the tumor communicated through a defect in the antero-inferior portion of the bony ear canal. No distant metastases were detected. Subsequently, the tumor was resected from the ear canal and the infratemporal fossa en bloc. Perioperatively the defect in the EAC wall was suspected of the foramen of Huschke. After the surgery, the older scans of the patient from the past showed no presence of a congenital EAC wall defect. Therefore, the authors concluded that the tumor aggressively grew through the bone due to its biological nature. CONCLUSION: Malignant myoepithelioma of the external auditory canal is an extremely rare condition and could be misdiagnosed as other benign lesions. In cases of suspicious lesions, it is advisable to do a probatory biopsy from the EAC. Surgery is the treatment of choice in malignant myoepitheliomas, and regular follow-ups are essential to monitor for recurrence or metastatic disease. Any mass located at the antero-inferior portion of the EAC wall warrants close evaluation due to its potential for expansion from the EAC.

Rare syringoid eccrine carcinoma of the upper lip and nasal base treated with resection and subsequent innovative reconstruction using an Abbé flap, turbinate flaps and three-stage forehead flap: a case report.

BACKGROUND: Although syringoma is a common benign tumour of the sudoriferous gland, there is also an extremely rare malignant form known as syringoid eccrine carcinoma (SEC). SEC usually exhibits slow growth with deep invasion and a frequent tendency to relapse. The treatment of choice is radical wide resection, which poses a difficult reconstructive problem, especially when the tumour is located in the centre of the face. CASE PRESENTATION: In this case, a 70-year-old man was diagnosed with an SEC at the same location as a benign syringoma of the upper lip and nasal base that had undergone primary excision 7 years prior. Primary radical resection was performed with immediate Abbé flap reconstruction. Nevertheless, histology revealed positive margins, and 3 additional re-excisions were needed to achieve clear margins. Four months after the initial resection, the patient had undergone an innovative reconstruction technique including not only the Abbé flap but also a turbinate flap harvested with functional endonasal surgery and a three-stage forehead flap. CONCLUSION: To the best of our knowledge, this is the first case report of a suspect malignant transformation of a benign syringoma after 7 years. In addition, from oncoplastic and reconstructive points of view, the bilateral use of the turbinate flap for reconstructing the intranasal lining of the alar base is unusual, and the use of functional endonasal surgery in nasal reconstruction for reducing the risk of damaging the vascular supply of the flap is innovative.

Bone invasion by oral squamous cell carcinoma.

BACKGROUND: With regards to the anatomical relationships in the mouth, oral squamous cell carcinoma can invade the maxilla or the mandible. According to the TNM system, tumours that invade through cortical bone are classified as T4a, stage IVA. Bone invasion by oral squamous cell carcinoma most often occurs in tumours close to the bone or in larger and more advanced tumours. It is considered an adverse prognostic factor and it is often a diagnostic and therapeutic problem. Destruction of the bone tissue is mediated by activated osteoclasts rather than directly by carcinoma. Tumor necrosis factors - receptor activator of NF-kB (RANK), receptor activator of NF-kB ligand (RANKL) and osteoprotegerin (OPG) - play an important role in osteoclastogenesis. According to histological point of view, there are three patterns of bone invasion - erosive, mixed and infiltrative. The most commonly used imaging techniques when evaluating bone invasion by oral squamous cell carcinoma include CT and MRI. PURPOSE: This review is focused on the cellular and molecular mechanisms, histological patterns and detection methods of bone invasion caused by oral squamous cell carcinoma.

Thymoma - diagnostics options.

Various types of tumors (either benign or malignant) can be found in mediastinum. Early diagnosis and treatment may help to improve survival and quality if life in these patients. Compared to direct mediastinoscopy, used for obtaining a specimen for histological analysis in previous decades, modern imaging methods, specifically the CT navigated biopsy, represent an effective and less invasive approach to the diagnosis. In our publication, we present a patient with thymoma, rather rare type of anterior mediastinum tumor.

Oncolysate-loaded Escherichia coli bacterial ghosts enhance the stimulatory capacity of human dendritic cells.

The natural adjuvant properties of bacterial ghosts (BGs) lie within the presence of intact pathogen-associated molecular patterns on their surface. BGs can improve the direct delivery, natural processing and presentation of target antigens within dendritic cells (DCs). Moreover, sensitization of human DCs by cancer cell lysate (oncolysate)-loaded BGs in the presence of IFN-α and GM-CSF enhanced DC maturation as indicated by an increased expression of maturation markers and co-stimulatory molecules, higher production of IL-12p70 and stimulation of significantly increased proliferation of both autologous CD4+ and CD8+ T cells compared to DCs matured in the presence of purified lipopolysaccharide. The induced T cells efficiently recognized oncolysate-derived tumor-associated antigens expressed by cancer cells used for the production of oncolysate. Our optimized one-step simultaneous antigen delivery and DC maturation-inducing method emerges as a promising tool for the development and implementation of next-generation cellular cancer immunotherapies.

Immune adjuvants as critical guides directing immunity triggered by therapeutic cancer vaccines.

Tumor growth is controlled by natural antitumor immune responses alone or by augmented immune reactivity resulting from different forms of immunotherapy, which has demonstrated clinical benefit in numerous studies, although the overall percentage of patients with durable clinical responses remains limited. This is attributed to the heterogeneity of the disease, the inclusion of late-stage patients with no other treatment options and advanced tumor-associated immunosuppression, which may be consolidated by certain types of chemotherapy. Despite variable responsiveness to distinct types of immunotherapy, therapeutic cancer vaccination has shown meaningful efficacy for a variety of cancers. A key step during cancer vaccination involves the appropriate modeling of the functional state of dendritic cells (DCs) capable of co-delivering four critical signals for proper instruction of tumor antigen-specific T cells. However, the education of DCs, either directly in situ, or ex vivo by various complex procedures, lacks standardization. Also, it is questioned whether ex vivo-prepared DC vaccines are superior to in situ-administered adjuvant-guided vaccines, although both approaches have shown success. Evaluation of these variables is further complicated by a lack of consensus in evaluating vaccination clinical study end points. We discuss the role of signals needed for the preparation of classic in situ and modern ex vivo DC vaccines capable of proper reprogramming of antitumor immune responses in patients with cancer.

Therapeutic dendritic cell-based cancer vaccines: the state of the art.

Dendritic cells (DCs) are the most potent professional antigen-presenting cells, capable of initiating proper adaptive immune responses. Although tumor-infiltrating DCs are able to recognize cancer cells and uptake tumor antigens, they often have impaired functions because of the immunosuppressive tumor milieu. Therefore, DCs are targeted by therapeutic means either in vivo or ex vivo to facilitate tumor antigen presentation to T cells and induce or promote efficient antitumor immune responses in cancer patients. This immunotherapeutical approach is defined as specific active tumor immunotherapy or therapeutic cancer vaccination. In this review we briefly discuss general aspects of DC biology, followed by a thorough description of the current knowledge and optimization trends of DC vaccine production ex vivo, including various approaches for the induction of proper DC maturation and efficient loading with tumor antigens. We also discuss critical clinical aspects of DC vaccine application in cancer patients, including protocols of administration (routes and regimens), individualization of tumor immunotherapy, prediction and proper evaluation of immune and clinical responses to immunotherapy, and the critical role of combining tumor immunotherapy with other cancer treatment strategies to achieve maximal therapeutic effects.

Multiple gene-to-gene interactions in children with sepsis: a combination of five gene variants predicts outcome of life-threatening sepsis.

INTRODUCTION: The aim of the study was to identify the dependency structure of genetic variants that can influence the outcome for paediatric patients with sepsis. METHODS: We evaluated the role of single nucleotide polymorphisms for five genes: bactericidal permeability increasing protein (BPI; rs5743507), lipopolysaccharide-binding protein (LBP; rs2232618), toll-like receptor 4 (TLR4; rs4986790), heat shock protein 70 (HSP 70; rs2227956), and interleukin 6 (IL-6; rs1800795) in 598 children aged 0 to 19 years that were admitted to a paediatric intensive care unit with fever, systemic inflammatory response syndrome, sepsis, severe sepsis, septic shock, or multiple organ dysfunction syndrome. A control group of 529 healthy individuals was included. Multi-way contingency tables were constructed and statistically evaluated using log-linear models. Typical gene combinations were found for both study groups. RESULTS: Detailed analyses of the five studied gene profiles revealed significant differences in sepsis survival. Stratification into high-risk, intermediate-risk, and low-risk groups of paediatric patients can predict the severity of sepsis. CONCLUSIONS: Analysis of single nucleotide polymorphisms for five genes can be used as a predictor of sepsis outcome in children.

MicroRNA profiling of activated and tolerogenic human dendritic cells.

Dendritic cells (DCs) belong to the immune system and are particularly studied for their potential to direct either an activated or tolerogenic immune response. The roles of microRNAs (miRNAs) in posttranscriptional gene expression regulation are being increasingly investigated. This study's aim is to evaluate the miRNAs' expression changes in prepared human immature (iDCs), activated (aDCs), and tolerogenic dendritic cells (tDCs). The dendritic cells were prepared using GM-CSF and IL-4 (iDC) and subsequently maturated by adding LPS and IFN-γ (aDC) or IL-10 and TGF-ß (tDC). Surface markers, cytokine profiles, and miRNA profiles were evaluated in iDC, tDC, and aDC at 6 h and 24 h of maturation. We identified 4 miRNAs (miR-7, miR-9, miR-155 and miR-182), which were consistently overexpressed in aDC after 6 h and 24 h of maturation and 3 miRNAs (miR-17, miR-133b, and miR-203) and miR-23b cluster solely expressed in tDC. We found 5 miRNAs (miR-10a, miR-203, miR-210, miR-30a, and miR-449b) upregulated and 3 miRNAs downregulated (miR-134, miR-145, and miR-149) in both tDC and aDC. These results indicate that miRNAs are specifically modulated in human DC types. This work may contribute to identifying specific modulating miRNAs for aDC and tDC, which could in the future serve as therapeutic targets in the treatment of cancer and autoimmune diseases.

[Dynamics of interleukin 6 levels in the patients with cardiogenic and septic shock and in a control group of patients with uncomplicated AMI]. / Dynamika hladiny interleukinu 6 u pacientu v septickém a kardiogenním soku a u pacientu s akutním infarktem myokardu s elevacemi ST.

INTRODUCTION: Cardiogenic shock (CS) is the leading cause of mortality in patients with acute myocardial infarction (AMI). Inflammatory response seems to be common response in patients with AMI, especially those with CS. We have therefore conducted a study to determine diagnostic and prognostic utility of interleukin 6 (IL6) levels in the cohort of patients with cardiogenic and septic shock (SS) and in a control group of patients with uncomplicated AMI. METHODS: In this prospective study 71 patients fulfilled the inclusion criteria: 30 patients with cardiogenic shock, 21 patients with septic shock and 20 patients with ST elevation myocardial infarction (STEMI). Plasma levels of IL6 were measured at 8 time points. The main endpoint was 3 month mortality. RESULTS: We have shown that the highest IL6 levels during the first week were recorded in patients with septic shock with peak value at admission. The maximum level of IL6 was detected between 12 to 24 hours after the onset of MI among patients with cardiogenic shock. According to Receiver operating characteristic (ROC) statistics levels of IL6 > 357 pg/ml at admission (AUC 0.730, p = 0.031) were typical for patients with CS in comparison with control group of STEMI patients. Values of IL6 > 1 237 pg/ml at admission and > 1 071 pg/ml at 24 hours (after admission?) were typical for thouse in septic shock in comparison with CS patients. We found only a non-significant trend of IL6 for the prediction of mortality in the cohort of CS patients for levels 1 854 pg/ml (AUC 0.769, p = 0.066) sampled 12 hours after admission. There was no association of plasma levels of IL6 with mortality in septic shock patients. CONCLUSIONS: Patients with cardiogenic shock demonstrated more pronounced cytokine response as evidenced by increased levels of IL6 compared to patients with uncomplicated STEMI. Levels of IL6 peaked in SS patients at admission, in CS patients 12-24 hours after admission. In daily clinical practice routine measurement of IL6 levels for prediction of prognosis both in cardiogenic and septic shock are of little value mainly due to significant interindividual variability of IL6 values.

A Tagging Polymorphism in Fat Mass and Obesity-Associated (FTO) Gene Is Associated with Sepsis Status in Children.

INTRODUCTION: Sepsis is one of the most common causes of death in patients admitted to intensive care units (ICUs). The development of sepsis is significantly influenced by genetic predisposition. In this study, we highlight a potential association between a variant of the fat mass and obesity-associated (FTO) gene and risk of sepsis in children and adolescents. METHODS: We investigated a first-intron tagging FTO polymorphism (rs17817449) by comparing a severe condition (SC) group, comprising 598 paediatric patients (ages 0-19 years) admitted to an ICU with fever, systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis, septic shock, or multiple organ dysfunction syndrome (MODS), with a control group consisting of 616 healthy young adults. RESULTS: We observed a lower prevalence (p < 0.01; OR = 0.59, 95% CI = 0.39-0.87) of the FTO TT genotype in febrile and SIRS patients compared to patients with severe illness. There was a borderline trend towards a lower prevalence of the FTO TT genotype in the control group compared to the SC group (p < 0.09, OR = 0.81, 95% CI = 0.62-1.06). CONCLUSIONS: Our findings suggest that rs17817449, a common FTO polymorphism, may be a predictor of sepsis in paediatric patients, and that higher body weight is protective against this clinical complication.

Juvenile Primary Sjögren Syndrome in a 15-Year-Old Boy with Renal Involvement: A Case Report and Review of the Literature.

Juvenile primary Sjögren syndrome (pSS) with renal involvement is extremely rare, reported approximately in 50 children, predominantly girls. Here, we present the first reported case of a male child with juvenile pSS with ocular surface disease (previously keratoconjunctivitis sicca), submandibular salivary gland involvement, and tubulointerstitial nephritis. First, two symptoms were clinically apparent at presentation. We illustrate here that kidney involvement in pSS should be actively looked for, as juvenile pSS may be associated with asymptomatic renal involvement. Immunophenotyping of peripheral blood cells using multicolor flow cytometry revealed at the time of diagnosis changes in both adaptive (T memory cells and B memory cells), and innate immunity (an increased activation of natural killer cells, as well as monocytes and neutrophils, and an increased representation of intermediate monocytes). Our case report points to the importance of kidney examination, early diagnosis and therapy in juvenile pSS, as well as highlights international collaboration to obtain more data for this rare disease.

Importance of evaluation of bone invasion type in squamous cell carcinomas of the oral cavity and oropharynx.

AIMS: The objective of this study was to compare bone invasion type with histopathological, clinical and immunohistochemical prognostic factors. METHODS: The study included 49 patients who were treated for oral squamous cell carcinoma. Of which, 30 patients, with presence of bone invasion on histopathology, were divided according to the type of bone invasion (erosive, infiltrative, mixed). Each invasion type was compared to microvascular density using the CD34 marker. RESULTS: The bone invasion was observed in 30 out of 49 patients (61.22%). On McNemar's test, statistically significant association was observed between bone invasion types and histopathological grade. In contrast, no significant correlation was observed between bone invasion type, and tumour volume or nodal metastases. In tumours with bone invasion of the infiltrative type, higher frequency of locoregional relapses was observed. The 5-year survival, since diagnosis, was approximately 60% in the erosive group, 40% in the mixed group, and merely 15% in the infiltrative group. CONCLUSION: Peritumoural microvascular density was not significantly related to bone invasion types. Whereas, a significantly higher intratumoural microvascular density was observed in infiltrative type of the bone invasion, when compared to the erosive and mixed type.

SMARCB1-deficient sinonasal adenocarcinoma: a rare variant of SWI/SNF-deficient malignancy often misclassified as high-grade non-intestinal-type sinonasal adenocarcinoma or myoepithelial carcinoma.

SMARCB1-deficient sinonasal adenocarcinoma is a rare variant of SWI/SNF-deficient malignancies with SMARCB1 loss and adenocarcinoma features. More than 200 high-grade epithelial sinonasal malignancies were retrieved. A total of 14 cases exhibited complete SMARCB1 (INI1) loss and glandular differentiation. SMARCA2 and SMARCA4 were normal, except for one case with a loss of SMARCA2. Next-generation sequencing (NGS) and/or fluorescence in situ hybridization (FISH) revealed an alteration in the SMARCB1 gene in 9/13 cases, while 2/13 were negative. Two tumors harbored SMARCB1 mutations in c.157C > T p.(Arg53Ter) and c.842G > A p.(Trp281Ter). One harbored ARID1B mutations in c.1469G > A p.(Trp490Ter) and MGA c.3724C > T p.(Arg1242Ter). Seven tumors had a SMARCB1 deletion. One carried an ESR1 mutation in c.644-2A > T, and another carried a POLE mutation in c.352_374del p.(Ser118GlyfsTer78). One case had a PAX3 mutation in c.44del p.(Gly15AlafsTer95). Histomorphology of SMARCB1-deficient adenocarcinoma was oncocytoid/rhabdoid and glandular, solid, or trabecular in 9/14 cases. Two had basaloid/blue cytoplasm and one showed focal signet ring cells. Yolk sac tumor-like differentiation with Schiller-Duval-like bodies was seen in 6/14 cases, with 2 cases showing exclusively reticular-microcystic yolk sac pattern. Follow-up of a maximum of 26 months (median 10 months) was available for 8/14 patients. Distant metastasis to the lung, liver, mediastinum, bone, and/or retroperitoneum was seen in 4/8 cases. Locoregional failure was seen in 75% of patients, with 6/8 local recurrences and 3 cervical lymph node metastases. At the last follow-up, 5 of 8 (62%) patients had died of their disease 2 to 20 months after diagnosis (median 8.2 months), and 3 were alive with the disease. The original diagnosis was usually high-grade non-intestinal-type adenocarcinoma or high-grade myoepithelial carcinoma. A correct diagnosis of these aggressive tumors could lead to improved targeted therapies with potentially better overall disease-specific survival.

Microbiota Diversity in Non-Small Cell Lung Cancer Gut and Mouth Cavity Microbiota Diversity in Non-Small Cell Lung Cancer Patients.

Lung malignancies have a substantial impact on cancer incidence and mortality worldwide. Even though many factors involved in the development of the disease are known, many questions remain unanswered. Previous studies suggest that the intestinal microbiota may have a role in developing malignant diseases. According to some findings, the microbiota has proven to be a key modulator of carcinogenic processes and the immune response against cancer cells, potentially influencing the effectiveness of immunotherapy. In our study, we characterized culturable microorganisms associated with non-small cell lung cancer (NSCLC) that can be recovered from rectal swabs and mouthwash. In addition, we also explored differences in the culturable microbiota with two main types of NSCLC - adenocarcinoma (ADC) and squamous cell carcinoma (SCC). With 141 patients included in the study (86 ADC and 55 SCC cases), a significant difference was observed between the two types in seven bacterial species (Collinsella, Corynebacterium, Klebsiella, Lactobacillus, Neisseria, Rothia, and Streptococcus), including the site of origin. The relationship between microbial dysbiosis and lung cancer is poorly understood; future research could shed light on the links between gut microbiota and lung cancer development.

Complex evaluation of human monocyte-derived dendritic cells for cancer immunotherapy.

Dendritic cell (DC) immunotherapy is capable of generating tumour-specific immune responses. Different maturation strategies were previously tested to obtain DC capable of anti-cancer responses in vitro, usually with limited clinical benefit. Mutual comparison of currently used maturation strategies and subsequent complex evaluation of DC functions and their stimulatory capacity on T cells was performed in this study to optimize the DC vaccination strategy for further clinical application. DC were generated from monocytes using granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4, pulsed with whole tumour cell lysate and then matured with one of five selected maturation strategies or cultured without additional maturation stimulus. DC were characterized with regard to their surface marker expression, cytokine profiles, migratory capacity, allogeneic and autologous T cell stimulatory capacity as well as their specific cytotoxicity against tumour antigens. We were able to demonstrate extensive variability among different maturation strategies currently used in DC immunotherapeutic protocols that may at least partially explain limited clinical benefit of some clinical trials with such DC. We identified DC matured with interferon-γ and lipopolysaccharide as the most attractive candidate for future clinical trials in cancer immunotherapy.

Delivery of large heterologous polypeptides across the cytoplasmic membrane of antigen-presenting cells by the Bordetella RTX hemolysin moiety lacking the adenylyl cyclase domain.

The Bordetella adenylate cyclase toxin-hemolysin (CyaA; also called ACT or AC-Hly) targets CD11b-expressing phagocytes and translocates into their cytosol an adenylyl cyclase (AC) that hijacks cellular signaling by conversion of ATP to cyclic AMP (cAMP). Intriguingly, insertion of large passenger peptides removes the enzymatic activity but not the cell-invasive capacity of the AC domain. This has repeatedly been exploited for delivery of heterologous antigens into the cytosolic pathway of CD11b-expressing dendritic cells by CyaA/AC(-) toxoids, thus enabling their processing and presentation on major histocompatibility complex (MHC) class I molecules to cytotoxic CD8(+) T lymphocytes (CTLs). We produced a set of toxoids with overlapping deletions within the first 371 residues of CyaA and showed that the structure of the AC enzyme does not contain any sequences indispensable for its translocation across target cell membrane. Moreover, replacement of the AC domain (residues 1 to 371) with heterologous polypeptides of 40, 146, or 203 residues yielded CyaAΔAC constructs that delivered passenger CTL epitopes into antigen-presenting cells (APCs) and induced strong antigen-specific CD8(+) CTL responses in vivo in mice and ex vivo in human peripheral blood mononuclear cell cultures. This shows that the RTX (repeats in toxin) hemolysin moiety, consisting of residues 374 to 1706 of CyaA, harbors all structural information involved in translocation of the N-terminal AC domain across target cell membranes. These results decipher the extraordinary capacity of the AC domain of CyaA to transport large heterologous cargo polypeptides into the cytosol of CD11b(+) target cells and pave the way for the construction of CyaAΔAC-based polyvalent immunotherapeutic T cell vaccines.

Epithelioid Soft Tissue Neoplasm of the Soft Palate with a PTCH1-GLI1 Fusion: A Case Report and Review of the Literature.

GLI1 fusions involving ACTB, MALAT1, PTCH1 and FOXO4 genes have been reported in a subset of malignant mesenchymal tumors with a characteristic nested epithelioid morphology and frequent S100 positivity. Typically, these multilobulated tumors consist of uniform epithelioid cells with bland nuclei and are organized into distinct nests and cords with conspicuously rich vasculature. We herein expand earlier findings by reporting a case of a 34-year-old female with an epithelioid mesenchymal tumor of the palate. The neoplastic cells stained positive for S100 protein and D2-40, whereas multiple other markers were negative. Genetic alterations were investigated by targeted RNA sequencing, and a PTCH1-GLI1 fusion was detected. Epithelioid mesenchymal tumors harboring a PTCH1-GLI1 fusion are vanishingly rare with only three cases reported so far. Due to the unique location in the mucosa of the soft palate adjacent to minor salivary glands, multilobulated growth, nested epithelioid morphology, focal clearing of the cytoplasm, and immunopositivity for S100 protein and D2-40, the differential diagnoses include primary salivary gland epithelial tumors, in particular myoepithelioma and myoepithelial carcinoma. Another differential diagnostic possibility is the ectomesenchymal chondromyxoid tumor. Useful diagnostic clues for tumors with a GLI1 rearrangement include a rich vascular network between the nests of neoplastic cells, tumor tissue bulging into vascular spaces, and absence of SOX10, GFAP and cytokeratin immunopositivity. Identifying areas with features of GLI1-rearranged tumors should trigger subsequent molecular confirmation. This is important for appropriate treatment measures as PTCH1-GLI1 positive mesenchymal epithelioid neoplasms have a propensity for locoregional lymph node and distant lung metastases.

MicroRNAs and glioblastoma: roles in core signalling pathways and potential clinical implications.

MicroRNAs (miRNAs) are endogenously expressed small non-coding RNAs that act as post-transcriptional regulators of gene expression. Dysregulation of these molecules has been indicated in the development of many cancers. Altered expression levels of several miRNAs were identified also in glioblastoma. It was repeatedly found that miRNAs are involved in important signalling pathways, which play roles in crucial cellular processes, such as proliferation, apoptosis, cell cycle regulation, invasion, angiogenesis and stem cell behaviour. Therefore, miRNAs represent promising therapeutic targets in glioblastoma. In this review, we summarize the current knowledge about miRNAs significance in glioblastoma, with special focus on their involvement in core signalling pathways, their roles in drug resistance and potential clinical implications.

MiR-195, miR-196b, miR-181c, miR-21 expression levels and O-6-methylguanine-DNA methyltransferase methylation status are associated with clinical outcome in glioblastoma patients.

Glioblastoma multiforme (GBM) is the most frequently occurring primary malignant brain tumor; patients with GBM often have a very poor prognosis and differing responses to treatment. Therefore, it is very important to find new biomarkers that can predict clinical outcomes and help in treatment decisions. MicroRNAs are small, non-coding RNAs that function as post-transcriptional regulators of gene expression and play a key role in the pathogenesis of GBM. In a group of 38 patients with primary GBM, we analyzed the expression of eight microRNAs (miR-21, miR-128a, miR-181c, miR-195, miR-196a, miR-196b, miR-221, and miR-222). In addition, we examined the methylation status of O-6-methylguanine-DNA methyltransferase (MGMT) promoter by high-resolution melting analysis, as this has been shown to be a predictive marker in GBM. MGMT methylation status correlated with progression-free survival (P = 0.0201; log-rank test) as well as with overall survival (P = 0.0054; log-rank test). MiR-195 (P = 0.0124; log-rank test) and miR-196b (P = 0.0492; log-rank test) positively correlated with overall survival. Evaluation of miR-181c in combination with miR-21 predicted time to progression within 6 months of diagnosis with 92% sensitivity and 81% specificity (P < 0.0001). Our data confirmed that the methylation status of MGMT but also miR-21, miR-181c, miR-195, and miR-196b to be associated with survival of GBM patients. Above all, we suggest that the combination of miR-181c and miR-21 could be a very sensitive and specific test to identify patients at high risk of early progression after surgery.