Leos Kren

Cytogenetic Prognostication Within Medulloblastoma Subgroups

PURPOSE Medulloblastoma comprises four distinct molecular subgroups: WNT, SHH, Group 3, and Group 4. Current medulloblastoma protocols stratify patients based on clinical features: patient age, metastatic stage, extent of resection, and histologic variant. Stark prognostic and genetic differences among the four subgroups suggest that subgroup-specific molecular biomarkers could improve patient prognostication. PATIENTS AND METHODS Molecular biomarkers were identified from a discovery set of 673 medulloblastomas from 43 cities around the world. Combined risk stratification models were designed based on clinical and cytogenetic biomarkers identified by multivariable Cox proportional hazards analyses. Identified biomarkers were tested using fluorescent in situ hybridization (FISH) on a nonoverlapping medulloblastoma tissue microarray (n = 453), with subsequent validation of the risk stratification models. RESULTS Subgroup information improves the predictive accuracy of a multivariable survival model compared with clinical biomarkers alone. Most previously published cytogenetic biomarkers are only prognostic within a single medulloblastoma subgroup. Profiling six FISH biomarkers (GLI2, MYC, chromosome 11 [chr11], chr14, 17p, and 17q) on formalin-fixed paraffin-embedded tissues, we can reliably and reproducibly identify very low-risk and very high-risk patients within SHH, Group 3, and Group 4 medulloblastomas. CONCLUSION Combining subgroup and cytogenetic biomarkers with established clinical biomarkers substantially improves patient prognostication, even in the context of heterogeneous clinical therapies. The prognostic significance of most molecular biomarkers is restricted to a specific subgroup. We have identified a small panel of cytogenetic biomarkers that reliably identifies very high-risk and very low-risk groups of patients, making it an excellent tool for selecting patients for therapy intensification and therapy de-escalation in future clinical trials.

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. (Cancer Sci 2011; 102: 2186–2190)

Expression of miRNA-106b in conventional renal cell carcinoma is a potential marker for prediction of early metastasis after nephrectomy

BackgroundMicroRNAs are endogenously expressed regulatory noncoding RNAs. Previous studies have shown altered expression levels of several microRNAs in renal cell carcinoma.MethodsWe examined the expression levels of selected microRNAs in 38 samples of conventional renal cell carcinoma (RCC) and 10 samples of non-tumoral renal parenchyma using TaqMan real-time PCR method.ResultsThe expression levels of miRNA-155 (p < 0.0001), miRNA-210 (p < 0.0001), miRNA-106a (p < 0.0001) and miRNA-106b (p < 0.0001) were significantly over-expressed in tumor tissue, whereas the expression of miRNA-141 (p < 0.0001) and miRNA-200c (p < 0.0001) were significantly decreased in RCC samples. There were no significant differences between expression levels of miRNA-182 and miRNA-200b in tumor samples and renal parenchyma. Our data suggest that expression levels of miRNA-106b are significantly lower in tumors of patients who developed metastasis (p = 0.030) and miR-106b is a potential predictive marker of early metastasis after nephrectomy in RCC patients (long-rank p = 0.032).ConclusionsWe have confirmed previous observations obtained by miRNA microarray analysis using standardized real-time PCR method. For the first time, we have identified a prognostic significance of miRNA-106b, which, after validation on a larger group of patients, maybe useful as a promising biomarker in patients with RCC.

Prognostic Significance of Anti-apoptosis Proteins Survivin and bcl-2 in Non-small Cell Lung Carcinomas: A Clinicopathologic Study of 102 Cases

Inhibitors of apoptosis, including bcl-2 and survivin (a novel gene encoding a unique apoptosis inhibitor), regulate cell proliferation by promoting cell survival. Although survivin has been detected in several human cancers, its prognostic significance and relationship to bcl-2 are not well characterized in lung cancer. Tissue sections from 102 non-small cell lung carcinomas (NSCLC) were immunostained using antibodies against survivin and bcl-2. Staining results were correlated with prognostic variables. Immunoreactivity for survivin and bcl-2 was observed in 53% and 21% of NSCLCs, respectively. Fifty-two percent of the 50 squamous cell carcinomas and 54% of the 52 adenocarcinomas expressed survivin. Survivin positivity correlated with tumor stage in squamous cell carcinoma. On univariate analysis, survivin expression correlated with decreased patient survival in NSCLC and in the subset of squamous cell carcinomas, but not in adenocarcinomas. On multivariate analysis, survivin was an independent predictor, along with distant metastasis and large tumor size. Eighteen percent of squamous cell carcinomas and 24% of adenocarcinomas expressed bcl-2. On univariate analysis, bcl-2 expression correlated with increased patient survival in NSCLC and in the subset of squamous cell carcinomas. An inverse correlation between the expression of survivin and bcl-2 was noted. Survivin immunoreactivity is an independent predictor of shortened survival in NSCLC, while bcl-2 protein expression correlated with prolonged patient survival. These findings indicate an inverse relationship between survivin and bcl-2 expression and suggest that these two inhibitors of apoptosis function through different pathways in the regulation of tumorigenesis in NSCLC.

Expression of immune-modulatory molecules HLA-G and HLA-E by tumor cells in glioblastomas: An unexpected prognostic significance?

The role of nonclassical human leukocyte antigens G and E (HLA‐G and HLA‐E) was originally thought to be restricted to the protection of the fetus from a maternal allorecognition. Now it is known that HLA‐G and HLA‐E exert multiple immunoregulatory functions. A prognostic significance of the expression of HLA‐G and HLA‐E by neoplastic cells in glioblastoma is not well characterized. In this study, we evaluated the expression of HLA‐G and HLA‐E by neoplastic cells in 39 cases of glioblastoma. We found the production of HLA‐G and HLA in a majority of cases. There was an unexpected positive correlation between the expression of HLA‐E and length of survival. We speculate that the expression of this molecule by neoplastic cells may represent a coincidental selective pro‐host advantage related to better response to subsequent therapeutic modalities. Mechanisms of glioblastoma cell pathophysiology and mechanisms of responses to therapeutic interventions in respect to the expression of these molecules deserves further study.

Allogeneic and autogenous transplantations of MSCs in treatment of the physeal bone bridge in rabbits

BackgroundThe aim of this experimental study on New Zealands white rabbits was to find differences in the results of treating the distal physeal femoral defect by the transplantation of autologous or allogeneic mesenchymal stem cells (MSCs). After the excision of a created bone bridge in the distal physis of the right femur, modified composite scaffold with MSCs was transplanted into the defect. In animal Group A (n = 11) autogenous MSCs were implanted; in animal Group B (n = 15) allogeneic MSCs were implanted. An iatrogenic physeal defect of the left femur of each animal not treated by MSCs transplantation served as control. The rabbits were euthanized four months after the transplantation. The treatment results were evaluated morphometrically (femoral length and valgus deformity measurement) and histologically (character and quality of the new cartilage).ResultsFour months after the transplantation, the right femurs of the animals in Group A were on average longer by 0.50 ± 0.04 cm (p = 0.018) than their left femurs, the right femurs of rabbits in Group B were on average longer by 0.43 ± 0.01 cm (p = 0.028) than their left femurs.4 months after the therapeutic transplantation of MSCs valgus deformity of the distal part of the right femur of animals in Group A was significantly lower (by 4.45 ± 1.86°) than that of their left femur (p = 0.028), in Group B as well (by 3.66 ± 0.95° than that of their left femur p = 0.001). However, no significant difference was found between rabbits with transplanted autogenous MSCs (Group A) and rabbits with transplanted allogeneic MSCs (Group B) either in the femur length (p = 0.495), or in its valgus deformity (p = 0.1597). After the MSCs transplantation the presence of a newly formed hyaline cartilage was demonstrated histologically in all the animals (both groups). The ability of transplanted MSCs to survive in the damaged physis was demonstrated in vivo by magnetic resonance, in vitro by Perls reaction and immunofluorescence.ConclusionThe transplantation of both autogenous and allogeneic MSCs into a defect of the growth plate appears as an effective method of surgical treatment of physeal cartilage injury. However, the Findings point to the conclusion that there is no clear difference in the final effect of the transplantation procedure used.

MiR-21, miR-34a, miR-198 and miR-217 as diagnostic and prognostic biomarkers for chronic pancreatitis and pancreatic ductal adenocarcinoma

BackgroundPancreatic ductal adenocarcinoma is an aggressive malignancy with late presentation, metastatic potential and very poor prognosis. Therefore, there is an urgent need for novel diagnostic and prognostic biomarkers. MicroRNAs are small non-coding RNAs that post-transcriptionally regulate gene expression. Altered expression of microRNAs has been reported in wide range of malignancies, including pancreatic ductal adenocarcinoma. The aim of this study was to analyze the expression of selected microRNAs in normal pancreas, chronic pancreatitis and pancreatic ductal adenocarcinoma tissues and evaluate their diagnostic and prognostic potential.FindingsUsing quantitative real-time PCR, expression levels of 4 microRNAs were examined in 74 tumor tissues, 18 tissues of chronic pancreatitis and 9 adjacent normal tissues and correlated with clinicopathological features of patients. Expression levels of miR-21, miR-34a and miR-198 were significantly higher, whereas levels of miR-217 were significantly lower in pancreatic ductal adenocarcinomas compared to healthy tissues and tissues of chronic pancreatitis. Moreover, increased expression of miR-21 and miR-198 was significantly associated with shorter disease free survival and overall survival.ConclusionsOur data suggest that altered expression of examined microRNAs is related to neoplastic transformation and progression of the disease and these microRNAs could serve as diagnostic and prognostic biomarkers for pancreatic ductal adenocarcinoma.Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1373952531543898

HLA-G and HLA-E specific mRNAs connote opposite prognostic significance in renal cell carcinoma

BackgroundRenal cell carcinoma (RCC) is characterized by its resistance to radiotherapy and/or chemotherapy. On the other hand, it is an immunogenic tumor - it is able to stimulate antitumor responses. A prognostic significance of HLA-G expression by neoplastic cells in RCC is not well characterized; significance HLA-E expression in RCC is not characterized at all.MethodsIn our study, we evaluated the expression of HLA-G and HLA-E specific mRNA transcripts produced by neoplastic cells in 38 cases of RCC and in 10 samples of normal kidney parenchyma. The results were statistically correlated with various clinico-pathological parameters.ResultsWe confirmed that HLA-G is downregulated in normal kidney tissue; if it is up-regulated in RCC, then it is connected to worse prognosis. On the other hand, HLA-E mRNA transcripts were present in both normal kidney tissue and RCC and their increasing concentrations counterintuitively carried better prognosis, more favorable pT stage and lower nuclear Fuhrmann’s grade.ConclusionConsidering the fact that there is known aberrant activation of HLA-G and HLA-E expression by interferons, identification of HLA-G and HLA-E status could contribute to better selection of RCC patients who could possibly benefit from more tailored neoadjuvant biological/immunological therapy. Thus, these molecules could represent useful prognostic biomarkers in RCC, and the expression of both these molecules in RCC deserves further study.The virtualSlide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/7383071387016614

Risk Score based on microRNA expression signature is independent prognostic classifier of glioblastoma patients

Glioblastoma multiforme (GBM) is the most malignant primary brain tumor. The prognosis of GBM patients varies considerably and the histopathological examination is not sufficient for individual risk estimation. MicroRNAs (miRNAs) are small, non-coding RNAs that function as post-transcriptional regulators of gene expression and were repeatedly proved to play important roles in pathogenesis of GBM. In our study, we performed global miRNA expression profiling of 58 glioblastoma tissue samples obtained during surgical resections and 10 non-tumor brain tissues. The subsequent analysis revealed 28 significantly deregulated miRNAs in GBM tissue, which were able to precisely classify all examined samples. Correlation with clinical data led to identification of six-miRNA signature significantly associated with progression free survival [hazard ratio (HR) 1.98, 95% confidence interval (CI) 1.33-2.94, P < 0.001] and overa+ll survival (HR 2.86, 95% CI 1.91-4.29, P < 0.001). O(6)-methylguanine-DNA methyltransferase methylation status was evaluated as reference method and Risk Score based on six-miRNA signature indicated significant superiority in prediction of clinical outcome in GBM patients. Multivariate Cox analysis indicated that the Risk Score based on six-miRNA signature is an independent prognostic classifier of GBM patients. We suggest that the Risk Score presents promising prognostic algorithm with potential for individualized treatment decisions in clinical management of GBM patients.

Multifunctional immune-modulatory protein HLA-E identified in classical Hodgkin lymphoma: Possible implications

Although the role of the non-classical human leukocyte antigen E (HLA-E) was originally thought to be limited to the development of a maternal tolerance to a semiallogeneic fetal graft, it is now known that HLA-E exerts multiple immunoregulatory functions. The significance of the presence of HLA-E in neoplastic cells and/or background microenvironment cells in classical Hodgkin lymphoma (cHL) is not well characterized. In our study, we evaluated the presence of HLA-E in both neoplastic and background cells in 40 cases of cHL. We found HLA-E in both neoplastic and background cells. There was a positive statistical correlation between the expression of HLA-E in neoplastic cells and the clinical stage of the disease, which indicates an immune-tolerogenic property of this multiple-purpose molecule. The presence of HLA-E in background cells seems to be prognostically neutral but its significance still needs to be determined. The mechanisms regulating the immunopathology of cHL neoplastic cells with respect to the presence of these molecule deserve further studies.