Masamitsu Nishihara

MicroRNA-10b is overexpressed in malignant glioma and associated with tumor invasive factors, uPAR and RhoC

MicroRNAs (miRNAs) are effective post‐transcriptional regulators of gene expression and are important in many biological processes. Although the oncogenic and tumor suppressive functions of several miRNAs have been characterized, the role of miRNAs in mediating tumor invasion and migration remains largely unexplored. Recently, miR‐10b was identified as an miRNA highly expressed in metastatic breast cancer, promoting cell migration and invasion. Here, we performed real‐time reverse transcriptase polymerase chain reaction (RT‐PCR) assays on 43 glioma samples (17 glioblastoma, 6 anaplastic astrocytoma, 10 low‐grade astrocytoma, 6 oligodendroglioma and 4 ependymoma) and 6 glioma cell lines. We found that miR‐10b expression was upregulated in all glioma samples compared to non‐neoplastic brain tissues. The expression levels of miR‐10b were associated with higher grade glioma. In addition, mRNA expressions of RhoC and urokinase‐type plasminogen activator receptor (uPAR), which were thought to be regulated by miR‐10b via HOXD10, were statistically significantly correlated with the expression of miR‐10b (p < 0.001, p = 0.001, respectively). Also, protein expression levels of RhoC and uPAR were associated with expression levels of miR‐10b (p = 0.009, p = 0.014, respectively). Finally, multifocal lesions on enhanced MRI of 7 malignant gliomas were associated with higher expression levels of miR‐10b (p = 0.02). Our data indicated that miR‐10b might play some role in the invasion of glioma cells.

Cerebrospinal fluid interleukin-10 is a potentially useful biomarker in immunocompetent primary central nervous system lymphoma (PCNSL)

The diagnosis of primary central nervous system lymphoma (PCNSL) by radiographical examination is often difficult because of its similarity to other brain tumors. To test whether interleukin-10 (IL-10) and IL-6 can be used to distinguish PCNSL from other brain tumors that are radiographically similar, cerebrospinal fluid (CSF) levels of IL-10 and IL-6 were measured in 66 patients with intracranial tumors (PCNSLs: 26 cases; other brain tumors: 40 cases). In the patients with PCNSLs, the median CSF levels of IL-10 and IL-6 were 27 pg/mL and 5.4 pg/mL, respectively. The CSF IL-10 and IL-6 levels were significantly higher in PCNSLs than in the other brain tumors. To validate the diagnostic value of CSF IL-10 in PCNSL, we prospectively examined 24 patients with brain lesions that were suspected to be PCNSL. We observed that the CSF IL-10 levels were significantly higher in PCNSLs than in other brain tumors. At an IL-10 cutoff level of 9.5 pg/mL, the sensitivity and specificity were 71.0% and 100%, respectively. After therapy, the CSF IL-10 levels were decreased in all patients and were increased at relapse in most of these patients. Immunohistochemically, all PCNSLs, except for 1 unclassified PCNSL, expressed both IL-10 and IL-10 receptor-A. In the patients with high CSF IL-10, IL-10 expression levels in tumor were relatively higher, compared with low CSF IL-10; however, there was no significant difference between these groups. In addition, elevated CSF level of IL-10 was significantly associated with having a shorter progression-free survival (hazard ratio, 3.37; 95% confidence interval, 0.985-11.528; log-rank, P= .038). These results indicate that the CSF level of IL-10 may be a useful diagnostic and prognostic biomarker in patients with PCNSLs.

MicroRNA-183 upregulates HIF-1α by targeting isocitrate dehydrogenase 2 (IDH2) in glioma cells

MicroRNAs (miRs) are small, non-coding RNAs that regulate gene expression and contribute to cell proliferation, differentiation and metabolism. Our previous study revealed the extensive modulation of a set of miRs in malignant glioma. In that study, miR microarray analysis demonstrated the upregulation of microRNA-183 (miR-183) in glioblastomas. Therefore, we examined the expression levels of miR-183 in various types of gliomas and the association of miR-183 with isocitrate dehydrogenase 2 (IDH2), which has complementary sequences to miR-183 in its 3′-untranslated region (3′UTR). In present study, we used real-time PCR analysis to demonstrate that miR-183 is upregulated in the majority of high-grade gliomas and glioma cell lines compared with peripheral, non-tumorous brain tissue. The mRNA and protein expression levels of IDH2 are downregulated via the overexpression of miR-183 mimic RNA in glioma cells. Additionally, IDH2 mRNA expression is upregulated in glioma cells expressing anti-miR-183. We verified that miR-183 directly affects IDH2 mRNA levels in glioma cells using luciferase assays. In malignant glioma specimens, the expression levels of IDH2 were lower in tumors than in the peripheral, non-tumorous brain tissues. HIF-1α levels were upregulated in glioma cells following transfection with miR-183 mimic RNA or IDH2 siRNA. Moreover, vascular endothelial growth factor and glucose transporter 1, which are downstream molecules of HIF-1α, were upregulated in cells transfected with miR-183 mimic RNA. These results suggest that miR-183 upregulation in malignant gliomas induces HIF-1α expression by targeting IDH2 and may play a role in glioma biology.

GC/MS-based metabolomic analysis of cerebrospinal fluid (CSF) from glioma patients

Metabolomics has recently undergone rapid development; however, metabolomic analysis in cerebrospinal fluid (CSF) is not a common practice. We analyzed the metabolite profiles of preoperative CSF samples from 32 patients with histologically confirmed glioma using gas chromatography/mass spectrometry (GC/MS). We assessed how alterations in the metabolite levels were related to the World Health Organization (WHO) tumor grades, tumor location, gadolinium enhancement on magnetic resonance imaging (MRI), and the isocitrate dehydrogenase (IDH) mutation status. Sixty-one metabolites were identified in the CSF from glioma patients using targeted, quantitative and non-targeted, semi-quantitative analysis. The citric and isocitric acid levels were significantly higher in the glioblastoma (GBM) samples than in the grades I–II and grade III glioma samples. In addition, the lactic and 2-aminopimelic acid levels were relatively higher in the GBM samples than in the grades I–II glioma samples. The CSF levels of the citric, isocitric, and lactic acids were significantly higher in grade I–III gliomas with mutant IDH than in those with wild-type IDH. The tumor location and enhancement obtained using MRI did not significantly affect the metabolite profiles. Higher CSF levels of lactic acid were statistically associated with a poorer prognosis in grades III–IV malignant gliomas. Our study suggests that the metabolomic analysis of CSF from glioma patients may be useful for predicting the glioma grade, metabolic state, and prognosis of gliomas.

Combined IDH1 mutation and MGMT methylation status on long-term survival of patients with cerebral low-grade glioma

OBJECTIVE The management of low-grade glioma (LGG) still remains controversial because the effectiveness of early and extensive resection is unclear, and the use of radiation therapy or chemotherapy is not well-defined. In particular, the importance of prognostic factors for survival remains a matter of discussion. The purpose of this study was to validate prognostic factors for survival in patients with LGG. MATERIALS AND METHODS A consecutive series of 55 patients with WHO grade II LGG treated in our institute between 1983 and 2013 were retrospectively reviewed to determine the prognostic factors for survival. All data were retrospectively analyzed from the aspect of baseline characteristics, pathological findings, genetic change, surgical treatments, adjuvant therapies, and survival time. Cox multivariate analysis was performed to determine the prognostic factors for survival. RESULTS There were 28 patients with diffuse astrocytoma (DA), 21 patients with oligodendroglioma (OG), and 6 patients with oligoastrocytoma (OA) diagnosed on initial surgery. The median overall survival was 193 months and fifteen patients (27.3%) died. A mutation in isocitrate dehydrogenase-1 (IDH1) was found in 72.9% of LGG, and this mutation was positively correlated with methylation of O6-methylguanine-DNA methyltransferase (MGMT) (p=0.02). A better prognosis was significantly associated with combined IDH1 mutation and MGMT methylation status (both positive vs both negative, HR 0.079 [95% CI 0.008-0.579], p=0.012), as well as histology (OG vs DA and OA, HR 0.158 [95% CI 0.022-0.674], p=0.011) and tumor size (<6 cm vs ≥6 cm, HR 0.120 [95% CI 0.017-0.595], p=0.008). CONCLUSIONS Tumor histology, size and IDH-mutation status are important predictors for prolonged overall survival in patients with LGG and may provide a reliable tool for standardizing future treatment strategies.

Rapid regrowth of an atypical choroid plexus papilloma located in the cerebellopontine angle

Choroid plexus papilloma usually occurs in the lateral or the fourth ventricle. Primary choroid plexus papilloma of the cerebellopontine angle, as described here, is an uncommon lesion. A 42-year-old man presented with a 1-month history of dysphagia and gait unsteadiness. CT scans and MRI showed a large extra-axial tumor in the right cerebellopontine angle. Pathological study revealed that the lesion was choroid plexus papilloma. Repeat imaging conducted 1 year after the operation showed that the tumor had recurred with distinct cystic features. Pathological examination again revealed increased mitotic activity and supported a diagnosis of atypical choroid plexus papilloma.

Patterns of failure after multimodal treatments for high-grade glioma: effectiveness of MIB-1 labeling index.

BackgroundThe purpose of the present study was to analyze the recurrence pattern of high-grade glioma treated with a multimodal treatment approach and to evaluate whether the MIB-1 labeling index (LI) could be a useful marker for predicting the pattern of failure in glioblastoma (GB).Methods and materialsWe evaluated histologically confirmed 131 patients with either anaplastic astrocytoma (AA) or GB. A median dose was 60 Gy. Concomitant and adjuvant chemotherapy were administered to 111 patients. MIB-1 LI was assessed by immunohistochemistry. Recurrence patterns were categorized according to the areas of recurrence as follows: central failure (recurrence in the 95% of 60 Gy); in-field (recurrence in the high-dose volume of 50 Gy; marginal (recurrence outside the high-dose volume) and distant (recurrence outside the RT field).ResultsThe median follow-up durations were 13 months for all patients and 19 months for those remaining alive. Among AA patients, the 2-year progression-free and overall survival rates were 23.1% and 39.2%, respectively, while in GB patients, the rates were 13.3% and 27.6%, respectively. The median survival time was 20 months for AA patients and 15 months for GB patients. Among AA patients, recurrences were central in 68.7% of patients; in-field, 18.8%; and distant, 12.5%, while among GB patients, 69.0% of recurrences were central, 15.5% were in-field, 12.1% were marginal, and 3.4% were distant. The MIB-1 LI medians were 18.2% in AA and 29.8% in GB. Interestingly, in patients with GB, the MIB-1 LI had a strong effect on the pattern of failure (P = 0.014), while the extent of surgical removal (P = 0.47) and regimens of chemotherapy (P = 0.57) did not.ConclusionsMIB-1 LI predominantly affected the pattern of failure in GB patients treated with a multimodal approach, and it might be a useful tool for the management of the disease.

Supratentorial Glioblastoma Treated with Radiotherapy: Use of the Radiation Therapy Oncology Group Recursive Partitioning Analysis Grouping for Predicting Survival

OBJECTIVE This study aimed to evaluate the usefulness of recursive partitioning analysis model established by the Radiation Therapy Oncology Group for predicting the survival of patients with supratentorial glioblastoma treated with radiotherapy and to determine prognostic factors for the subgroups of this prognostic model. METHODS A total of 108 glioblastoma patients treated with radiotherapy between January 1987 and December 2005 were retrospectively reviewed. Recursive partitioning analysis classes III, IV, V and VI included 8, 29, 32 and 39 patients, respectively. These classes were divided into two subgroups: a good prognostic group containing classes III-IV and a poor prognostic group containing classes V-VI. The median radiation dose was 60 Gy. Seventy-five patients received chemotherapy and/or immunotherapy. RESULTS The overall survival differed significantly among classes III, IV, V and VI, with median survival times of 34, 15, 11 and 7 months, respectively. Among the good prognostic group, patients with basal ganglia invasion showed poorer survival outcomes than patients without basal ganglia invasion. Among the poor prognostic group, patients with tumor sizes of <5 cm and patients treated with nimustine hydrochloride showed better survival outcomes than those with tumor sizes of > or =5 cm and those without treatment with nimustine hydrochloride, respectively. CONCLUSIONS This study confirms the prognostic value of the recursive partitioning analysis grouping. Basal ganglia invasion could be a useful predictive factor for survival in the good prognostic group, whereas tumor size and treatment with nimustine hydrochloride could be useful predictive factors in the poor prognostic group.

Tumor-Associated Macrophages Associate with Cerebrospinal Fluid Interleukin-10 and Survival in Primary Central Nervous System Lymphoma (PCNSL).

Increased tumor‐associated macrophages (TAMs) have been reported to be associated with poor prognosis in various tumors; however, the importance of TAMs in primary central nervous system lymphoma (PCNSL) has not been clarified. In 47 patients with PCNSL who were treated with high‐dose methotrexate (MTX) and radiotherapy, the relationships between the infiltration levels of TAMs and the clinicopathological parameters were analyzed. Univariate analysis of the Cox proportional hazards model using continuous scales revealed that increased CD68 positive (+) TAMs was significantly associated with inferior progression‐free survival (PFS) (P = 0.04), and trends were observed for the increased CD163+ TAMs and having shorter PFS (P = 0.05). However, increased TAMs were not associated with overall survival. Because TAMs are known to produce various cytokines, we examined the relationships between cerebrospinal fluid (CSF) cytokines and TAMs. CSF interleukin‐6 (IL‐6) and soluble IL‐2 receptor were not correlated with the infiltration rate of TAMs; however, CSF IL‐10 level was correlated with infiltration levels of CD68 and CD163+ TAMs. We also confirmed the expression of IL‐10 in CD68+ and CD163+ TAMs by double immunostaining analysis. Our results indicate that a high level of IL‐10 in CSF may be positively associated with the infiltration level of TAMs in PCNSLs.

Supratentorial pure cortical ependymoma.

Ependymoma usually occurs in the lateral or the fourth ventricle. Supratentorial extraventricular ependymoma is relatively rare. However, extraventricular ependymoma located at the cerebral cortex is extremely rare. We treated a 20-year-old woman who presented with generalized seizures. Cranial CT scan revealed a calcified mass in the left precentral gyrus. MRI confirmed an extraventricular, 12-mm-diameter intracortical mass. After gadolinium injection, tumor enhancement was mild and heterogeneous. The tumor was totally resected without neurological deterioration. Histological features were consistent with ependymoma, forming perivascular pseudorosettes without anaplastic figures. Immunohistochemistry showed positive staining for glial fibrillary acidic protein, S-100, and epithelial membrane antigen. A diagnosis of ependymoma of World Health Organization grade II was made. The patient has not had a seizure since the operation. There has been no clinical or radiologic evidence of recurrence during a 16-month postoperative follow-up.