Expression of CD133 as a Putative Prognostic Biomarker to Predict Intracranial Dissemination of Primary Spinal Cord Astrocytoma

OBJECTIVE

Spinal cord astrocytoma with intracranial dissemination carries a poor prognosis. The mechanisms leading to dissemination remain to be elucidated. A stem cell marker, CD133, was reported to predict recurrence patterns in intracranial glioblastoma. We evaluated the significance of CD133 as a putative prognostic biomarker to predict intracranial dissemination in spinal cord astrocytoma.

METHODS

This study included 14 consecutive patients with primary spinal cord astrocytoma treated from 1998 to 2014. Six of the patients were women and the patients' ages ranged from 12 to 75 years. Seven and 6 patients underwent open biopsy and partial resection of the tumors, respectively. After confirmation of the histologic diagnoses, all patients were treated with postoperative radiotherapy, chemotherapy, or a combination of both. To identify factors predictive of intracranial dissemination, we analyzed their clinical data including Ki-67 labeling index, and CD133 expression.

RESULTS

Intracranial dissemination was observed in 6 of 14 patients. All 6 patients died during the follow-up period. Of the 8 patients without intracranial dissemination, 5 survived (P = 0.02). Median survival for the patients with intracranial dissemination was 22.7 months. CD133 expression was significantly higher in patients with intracranial dissemination (P = 0.04), whereas other variables did not indicate the dissemination.

CONCLUSIONS

The expression of CD133 can be an efficient biomarker to predict intracranial dissemination in spinal cord astrocytoma. Recognition of high CD133 expression in surgical specimens and early detection of intracranial dissemination is important for the clinical management of spinal cord astrocytoma.

Glioblastoma in neurofibromatosis 1 patients without IDH1, BRAF V600E, and TERT promoter mutations

Pilocytic astrocytomas and low-grade gliomas are more common compared with glioblastomas in patients with neurofibromatosis 1 (NF1). A recent genome-wide analysis has shown frequent NF1 gene alterations in the mesenchymal subtype of a glioblastoma; however, little is known about clinicopathological features of glioblastomas in NF1 patients (NF1 glioblastomas). We analyzed four NF1 glioblastomas. Radiographical and intraoperative findings showed well-circumscribed tumors from surrounding brain. Pathological analysis presented a paucity of processes with an eosinophilic cytoplasm, bizarre nuclei, xanthomatous-like appearance, multinucleated giant cells, and histiocytoid appearance. During the follow-up period, one patient died at 49 months and others remained alive for 60, 87, and 106 months; thus, patients with NF1 glioblastoma presented a relatively favorable survival. None of the NF1 glioblastomas harbored isocitrate dehydrogenase 1 (IDH1) gene mutation, v-RAF murine sarcoma viral oncogene homolog B1 (BRAF) gene mutation, and telomerase reverse transcriptase (TERT) gene promoter mutation. We identified that NF1 glioblastoma is a unique subset of glioblastoma.

Intraoperative Visualization of Subependymal Arteries at the Atrium Supplying the Descending Motor Pathway

OBJECTIVE

We previously disclosed that damage to the subependymal arteries (SEAs) caused by coagulation of the choroid plexus at the atrium can result in infarction within the lateral posterior choroidal artery territory, followed by hemiparesis. The present study describes the intraoperative anatomical findings of the SEAs and choroid plexus at the atrium, which were verified only by a few cadaveric studies.

METHODS

Locations of the SEA and descending motor pathway were determined with the neuronavigation system and subcortical electrical stimulation in 8 cases of periatrial brain tumor. Indocyanine green videoangiography was performed to verify the blood flow in the choroid plexus and SEAs.

RESULTS

Intraoperative visualization of the SEAs was performed successfully in all patients. The neuronavigation system and subcortical electrical stimulation mapping demonstrated that these SEAs penetrated into the descending motor pathway. Indocyanine green depicted the blood flow of the SEAs entering the wall of the lateral ventricle and adjacent brain parenchyma. The blood flow directions between the SEAs and choroid plexus were not uniform, because the SEAs were filled ahead of the choroid plexus in 3 cases, whereas the choroid plexus was filled first in the other 2 cases.

CONCLUSIONS

Manipulations to the inner side of the choroid plexus at the transition from the atrium to the body of lateral ventricle can damage the SEAs. Not only coagulation of the SEAs themselves, but also coagulation of choroid plexus itself may reduce the blood flow in the SEAs, resulting in ischemic complications at descending motor pathway.

Local convection-enhanced delivery of an anti-CD40 agonistic monoclonal antibody induces antitumor effects in mouse glioma models

BACKGROUND

Glioblastoma is one of the most malignant brain tumors in adults and has a dismal prognosis. In a previous report, we reported that CD40, a TNF-R-related cell surface receptor, and its ligand CD40L were associated with glioma outcomes. Here we attempted to activate CD40 signaling in the tumor and determine if it exerted therapeutic efficacy.

METHODS

CD40 expression was examined in 3 mouse glioma cell lines (GL261, NSCL61, and bRiTs-G3) and 5 human glioma cell lines (U87, U251, U373, T98, and A172). NSCL61 and bRiTs-G3, as glioma stem cells, also expressed the glioma stem cell markers MELK and CD44. In vitro, we demonstrated direct antitumor effects of an anti-CD40 agonistic monoclonal antibody (FGK45) against the cell lines. The efficacy of FGK45 was examined by local convection-enhanced delivery of the monoclonal antibody against each glioma model.

RESULTS

CD40 was expressed in all mouse and human cell lines tested and was found at the cell membrane of each of the 3 mouse cell lines. FGK45 administration induced significant, direct antitumor effects in vitro. The local delivery of FGK45 significantly prolonged survival compared with controls in the NSCL61 and bRiTs-G3 models, but the effect was not significant in the GL261 model. Increases in apoptosis and CD4(+) and CD8(+) T cell infiltration were observed in the bRiTs-G3 model after FGK45 treatment.

CONCLUSIONS

Local delivery of FGK45 significantly prolonged survival in glioma stem cell models. Thus, local delivery of this monoclonal antibody is promising for immunotherapy against gliomas.

CD40/CD40L expression correlates with the survival of patients with glioblastomas and an augmentation in CD40 signaling enhances the efficacy of vaccinations against glioma models

BACKGROUND

The prognosis of glioblastoma (GBM) remains poor; therefore, effective therapeutic strategies need to be developed. CD40 is a costimulatory molecule whose agonistic antibody has been shown to activate antitumor effects. Recently, CD40 has been extensively targeted for immunotherapeutic purposes.

METHODS

Expressions of CD40/CD40L mRNAs were examined in 86 cases of World Health Organization grade IV GBM and 36 cases of grade III gliomas and correlated with outcomes. CD40 signaling was employed to augment the efficacy of immunotherapy against gliomas. The efficacy of FGK45, an agonistic antibody for CD40, was examined by adding it to a tumor lysate-based subcutaneous vaccination against a GL261 glioma model and an NSCL61 glioma-initiating cell-like cell tumor model.

RESULTS

We demonstrated for the first time using quantitative PCR that grade III gliomas express higher levels of CD40/CD40L than does grade IV GBM. The higher expression of CD40/CD40L was associated with good prognoses in patients with GBM. Addition of FGK45 to the subcutaneous tumor cell lysate-based vaccination significantly prolonged survival in both tumor models. However, the efficacy was modest in NSCL61-model mice. Therefore, we established combination immunotherapeutic strategies using FGK45 and OX86, an agonistic antibody for OX40. Combination immunotherapy significantly prolonged survival with synergistic effects. Apoptosis increased and proliferation decreased in tumors treated with combination immunotherapy.

CONCLUSIONS

The high expression of CD40/CD40L can be used as a biomarker for better prognoses in patients with gliomas. Immunotherapy using FGK45 significantly prolonged survival and represents a potential therapeutic strategy for gliomas including glioma-initiating cells.

OX40 ligand expressed in glioblastoma modulates adaptive immunity depending on the microenvironment: a clue for successful immunotherapy

Background

Glioblastoma is the most malignant human brain tumor and has a dismal prognosis; however, some patients show long-term survival. The interaction between the costimulatory molecule OX40 and its ligand OX40L generates key signals for T-cell activation. The augmentation of this interaction enhances antitumor immunity. In this present study, we explored whether OX40 signaling is responsible for antitumor adaptive immunity against glioblastoma and also established therapeutic antiglioma vaccination therapy.

Methods

Tumor specimens were obtained from patients with primary glioblastoma (n = 110) and grade III glioma (n = 34). Quantitative polymerase chain reaction (PCR), flow cytometry, and immunohistochemistry were used to analyze OX40L expression in human glioblastoma specimens. Functional consequences of OX40 signaling were studied using glioblastoma cell lines, mouse models of glioma, and T cells isolated from human subjects and mice. Cytokine production assay with mouse regulatory T cells was conducted under hypoxic conditions (1.5% O₂).

Results

OX40L mRNA was expressed in glioblastoma specimens and higher levels were associated with prolonged progression-free survival of patients with glioblastoma, who had undergone gross total resection. In this regard, OX40L protein was expressed in A172 human glioblastoma cells and its expression was induced under hypoxia, which mimics the microenvironment of glioblastoma. Notably, human CD4 T cells were activated when cocultured in anti-CD3-coated plates with A172 cells expressing OX40L, as judged by the increased production of interferon-γ. To confirm the survival advantage of OX40L expression, we then used mouse glioma models. Mice bearing glioma cells forced to express OX40L did not die during the observed period after intracranial transplantation, whereas all mice bearing glioma cells lacking OX40L died. Such a survival benefit of OX40L was not detected in nude mice with an impaired immune system. Moreover, compared with systemic intraperitoneal injection, the subcutaneous injection of the OX40 agonist antibody together with glioma cell lysates elicited stronger antitumor immunity and prolonged the survival of mice bearing glioma or glioma-initiating cell-like cells. Finally, OX40 triggering activated regulatory T cells cultured under hypoxia led to the induction of the immunosuppressive cytokine IL10.

Conclusion

Glioblastoma directs immunostimulation or immunosuppression through OX40 signaling, depending on its microenvironment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0307-3) contains supplementary material, which is available to authorized users.

Activation of the NRF2 pathway and its impact on the prognosis of anaplastic glioma patients

BACKGROUND

Nuclear factor erythroid 2-related factor 2 (NRF2) plays pivotal roles in cytoprotection. We aimed at clarifying the contribution of the NRF2 pathway to malignant glioma pathology.

METHODS

NRF2 target gene expression and its association with prognosis were examined in 95 anaplastic gliomas with or without isocitrate dehydrogenase (IDH) 1/2 gene mutations and 52 glioblastomas. To explore mechanisms for the altered activity of the NRF2 pathway, we examined somatic mutations and expressions of the NRF2 gene and those encoding NRF2 regulators, Kelch-like ECH-associated protein 1 (KEAP1) and p62/SQSTSM. To clarify the functional interaction between IDH1 mutations and the NRF2 pathway, we introduced a mutant IDH1 to T98 glioblastoma-derived cells and examined the NRF2 activity in these cells.

RESULTS

NRF2 target genes were elevated in 13.7% and 32.7% of anaplastic gliomas and glioblastomas, respectively. Upregulation of NRF2 target genes correlated with poor prognosis in anaplastic gliomas but not in glioblastomas. Neither somatic mutations of NRF2/KEAP1 nor dysregulated expression of KEAP1/p62 explained the increased expression of NRF2 target genes. In most cases of anaplastic glioma with mutated IDH1/2, NRF2 and its target genes were downregulated. This was reproducible in IDH1 R132H-expressing T98 cells. In minor cases of IDH1/2-mutant anaplastic gliomas with increased expression of NRF2 target genes, the clinical outcomes were significantly poor.

CONCLUSIONS

The NRF2 activity is increased in a significant proportion of malignant gliomas in general but decreased in the majority of IDH1/2-mutant anaplastic gliomas. It is plausible that the NRF2 pathway plays an important role in tumor progression of anaplastic gliomas with IDH1/2 mutations.

Malignant clinical features of anaplastic gliomas without IDH mutation

BACKGROUND

Diagnosis of WHO grade III anaplastic gliomas does not always correspond to its clinical outcome because of the isocitrate dehydrogenase (IDH) gene status. Anaplastic gliomas without IDH mutation result in a poor prognosis, similar to grade IV glioblastomas. However, the malignant features of anaplastic gliomas without IDH mutation are not well understood. The aim of this study was to examine anaplastic gliomas, in particular those without IDH mutation, with regard to their malignant features, recurrence patterns, and association with glioma stem cells.

METHODS

We retrospectively analyzed 86 cases of WHO grade III anaplastic gliomas. Data regarding patient characteristics, recurrence pattern, and prognosis were obtained from medical records. We examined molecular alterations such as IDH mutation, 1p19q loss, TP53 mutation, MGMT promoter methylation, Ki67 labeling index, and CD133, SOX2, and NESTIN expression.

RESULTS

Of the 86 patients with anaplastic gliomas, 58 carried IDH mutation, and 40 experienced recurrence. The first recurrence was local in 25 patients and distant in 15. Patients without IDH mutation exhibited significantly higher CD133 and SOX2 expression (P = .025 and .020, respectively) and more frequent distant recurrence than those with IDH mutation (P = .022).

CONCLUSIONS

Patients with anaplastic gliomas without IDH mutation experienced distant recurrence and exhibited glioma stem cell markers, indicating that this subset may share some malignant characteristics with glioblastomas.

Rapid and sensitive intraoperative detection of mutations in the isocitrate dehydrogenase 1 and 2 genes during surgery for glioma

Object

Intraoperative diagnosis is important in determining the strategies during surgery for glioma. Because the mutations in the isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) genes have diagnostic, prognostic, and predictive values, the authors assessed the feasibility and significance of a simplified method for the intraoperative detection of IDH1 and IDH2 gene mutations.

Methods

Rapid DNA extraction, amplification with conventional polymerase chain reaction (PCR) or co-amplification at lower denaturation temperature PCR (COLD-PCR), and fluorescence melting curve analysis with adjacent hybridization probes were performed for the intraoperative detection of IDH1 and IDH2 mutations in 18 cases of suspected nonneoplastic lesions and low- and high-grade gliomas and in 3 cases of radiation necrosis.

Results

DNA extraction for detection of the mutation took 60–65 minutes. The results of this assay showed complete correlation with that of Sanger sequencing. The sensitivity for detection of mutations in a background of wild-type genes was 12.5% and 2.5% in conventional PCR and COLD-PCR, respectively. The diagnosis of glioma was established in 3 of 5 cases in which definitive diagnosis was not obtained using frozen sections, and information was obtained for the discrimination of glioblastoma or glioblastoma with an oligodendroglioma component from anaplastic glioma or secondary glioblastoma. This assay also detected a small fraction of tumor cells with IDH1 mutation in radiation necrosis.

Conclusions

These methods provide important information for establishing the differential diagnosis between low-grade glioma and nonneoplastic lesions and the diagnosis for subtypes of high-grade glioma. Although tumor cells in radiation necrosis were detected with a high sensitivity, further investigation is necessary for clinical application in surgery for recurrent glioma.

Summary of 15 years experience of awake surgeries for neuroepithelial tumors in tohoku university

We retrospectively analyzed 15 years experience of awake surgeries for neuroepithelial tumors in Tohoku University. Awake surgeries mostly for language mapping were performed for 42 of 681 newly diagnosed cases (6.2%) and 59 of 985 surgeries including for recurrence (6.0%). When the same histologies and locations as cases resected under awake condition are selected from the parent population treated by radical resection, awake surgeries were most frequently performed for 14 of 55 newly diagnosed cases (25.5%) and 14 of 62 surgeries (22.6%) with grade II gliomas. In the results, 8 of 59 surgeries (13.6%) could not achieve complete language monitoring until the final stage of tumor resection, considered as failed awake surgery. Gross total resection was accomplished in 20 of 42 newly diagnosed cases (47.6%) and 32 of 59 surgeries (54.2%). Mortality rate was 0%. Late severe deficits were observed in 2 of 42 newly diagnosed cases (4.8%) and 3 of 59 surgeries (5.1%). Negative language mapping cases did not suffer severe deficits in both early and late stages. In contrast, high incidence of severe deficits, 3 as early and 2 as late of 8 cases, were identified with failed awake surgery. The overall survival of patients treated by awake surgery compared favorably with those treated without stimulation mapping and with stimulation mapping under general anesthesia. Awake surgery may contribute to improve the outcome of gliomas near eloquent areas by maximizing the tumor resection and minimizing the surgical morbidity.

Treatment results of glioblastoma during the last 30 years in a single institute

Treatment results of glioblastoma (GB) during the last 30 years in Tohoku University were analyzed to identify any improvements in patient outcome in all 332 histologically proven cases of newly diagnosed GB treated consecutively in our department between 1982 and 2011. These 30 years was divided into 5 treatment eras, Group 1 (1982–1988, without preoperative evaluation by magnetic resonance [MR] imaging, n = 46), Group 2 (1989–1996, with preoperative MR imaging, n = 41), Group 3 (1997–1999, additionally underwent intraoperative functional brain mapping and neuronavigation system, n = 38), Group 4 (2000–August 2006, underwent 30 Gy of whole brain radiation followed by 30 Gy of extended local accelerated hyperfractionated radiation therapy, n = 96), and Group 5 (September 2006–2011, adjuvant usage of temozolomide [TMZ], n = 111). Overall survival (OS) was calculated from the date of surgery to the death from any cause. The median survival time/2-year OS/5-year OS of Groups 1 to 5 were 10.7 months/10.9%/0%, 17.3 months/26.2%/6.9%, 15.9 months/23.7%/5.3%, 20.1 months/34.8%/15.5%, and 20.9 months/45.5%/19.7%. The prognosis for patients with GB improved significantly after the introduction of MR imaging. Younger GB, defined as patients aged below 60 years, or total tumor resection with all ages in Group 5 had 5-year 0S of 31.0% and 30.1%, respectively. The prognosis of GB was improved significantly after the introduction of TMZ for elderly GB, recursive partitioning analysis class 5, or totally resected GB. Introduction of MR imaging and TMZ, and total resection of the tumor were important in the improvement of outcome for patients with GB.

The expression status of CD133 is associated with the pattern and timing of primary glioblastoma recurrence

BACKGROUND

Glioblastoma carries a poor prognosis primarily because of its high rate of recurrence. The ability to predict the recurrence pattern and timing would be highly useful for determining effective treatment strategies. We examined the correlation between prognostic factors and the pattern of recurrence in patients with primary glioblastoma. In particular, we examined whether there was a correlation between the expression of CD133 and glioblastoma recurrence.

METHODS

We retrospectively analyzed 112 patients with primary glioblastoma. The timing and pattern (local or distant) of the initial recurrence were obtained from medical records. To identify factors predictive of recurrence, we examined CD133 expression by Western blots and immunohistochemistry, clinical (age, sex, KPS, Ki67 labeling index, surgery, ventricular entry) and genetic (IDH1, 7p, 9p, 10q, MGMT) factors.

RESULTS

Of the 112 patients, 99 suffered recurrence. The first recurrence was local in 77 patients and distant in 22 patients. Among the factors to predict the pattern of recurrence, CD133 expression was significantly higher in distant than in local recurrence. Of the factors to predict the timing of recurrence, high CD133 expression was associated with shorter time to distant recurrence in both univariate and multivariate analyses (P = .0011 and P = .038, respectively).

CONCLUSIONS

The expression of CD133 may be a predictor of the pattern and timing of recurrence of primary glioblastoma.

Dynamic changes in magnetic resonance imaging appearance of dysembryoplastic neuroepithelial tumor with or without malignant transformation

Dysembryoplastic neuroepithelial tumors (DNETs) have conventionally been regarded as benign and stable tumors and considered curable with surgery without adjunctive therapy. Recently, recurrent DNETs with or without malignant transformation have been described. The authors report 2 unusual cases of DNET: 1) an enlarging lesion that developed an enhancing component over the natural course of 4 years, and 2) a recurrent DNET that developed an enhancing component 10-11 years after gross-total resection. The patient in the first case was treated with subtotal resection and adjuvant radiochemotherapy; histological examination of the tumor led to the diagnosis of DNET, WHO Grade I, for the nonenhancing component and anaplastic oligodendroglioma, WHO Grade III, for the enhancing component. The patient in the second case was treated with repeat gross-total resection; the original tumor had been histologically diagnosed as DNET, and the nonenhancing and enhancing components of the recurrent tumor were diagnosed as simple and complex forms of DNET, respectively. These and previous reports suggest an aggressive subtype of DNETs. If follow-up MRI reveals progressive behavior, resection should be performed without delay. Additional radiochemotherapy is needed if the histological diagnosis demonstrates malignant transformation.

Increase in the number of patients with seizures following the Great East-Japan Earthquake

In the afternoon of March 11, 2011, Kesennuma City was hit by the Great East-Japan Earthquake and a devastating tsunami. The purpose of this retrospective study is to document possible changes in the number of patients with distinct neurologic diseases seeking treatment following this disaster. Because of Kesennuma's unique geographical location, the city was isolated by the disaster, allowing for a study with relatively limited population selection bias. Patients admitted for neurologic emergencies from January 14 to May 5 in 2011 (n = 117) were compared with patients in the corresponding 16-week periods in 2008-2010 (n = 323). The number of patients with unprovoked seizures was significantly higher during the 8-week period after the earthquake (n = 13) than during the same periods in 2008 (n = 6), 2009 (n = 3), and 2010 (no patients) (p = 0.0062). In contrast, the number of patients treated for other neurologic diseases such as stroke, trauma, and tumors remained unchanged. To our knowledge, this is the first report of an increase in the number of patients with seizures following a life-threatening natural disaster. We suggest that stress associated with life-threatening situations may enhance seizure generation.

Clinical and histological characteristics of recurrent oligodendroglial tumors: comparison between primary and recurrent tumors in 18 cases

Changes in histological and genetic characteristics were investigated in 18 paired primary and recurrent oligodendroglial tumors, using sequencing analysis for isocitrate dehydrogenase (IDH) 1 and 2 gene mutation, Ki-67 and p53 immunohistochemistry, and fluorescent in situ hybridization for loss of heterozygosity of chromosomes 1p and 19q (1p/19q co-deletion). Malignant transformation occurred in 5 of 8 cases with World Health Organization (WHO) grade II tumors, but in 0 of 10 cases with WHO grade III tumors progressing to glioblastoma. Thirteen of the 18 cases carried IDH1 gene mutation. Tumors with IDH1 mutation tended to survive for longer, even after recurrence, but newly developed microvascular proliferation, tumor necrosis, and elevated Ki-67 labeling index were common. Eleven of the 13 IDH1-mutation tumors had either 1p/19q co-deletion or nuclear expression of p53, but all 5 IDH1/2 wild-type tumors had neither. All cases had the same profile for 1p/19q status at recurrence, but nuclear expression of p53 changed from negative to positive in 2 of 6 cases with IDH1 mutation and 1p/19q co-deletion. WHO grade II oligodendroglial tumors show a high rate of malignant transformation, possibly involving p53 in tumors with IDH1 mutation and 1p/19q co-deletion. Tumors with IDH1 mutation had a more aggressive histological phenotype despite their better prognosis.

IDH1/2 gene status defines the prognosis and molecular profiles in patients with grade III gliomas

BACKGROUND

The discovery of isocitrate dehydrogenase 1 and 2 gene (IDH1/2) mutations has enabled grade III glioma to be divided into mutated and wild-type IDH1/2 groups, which are known to carry different prognosis and molecular features. However, detailed subgroup analysis of grade III glioma is limited. To address this, we investigated molecular and prognostic features of grade III glioma with and without IDH1/2 mutation.

METHODS

We retrospectively analyzed 115 grade III glioma patients. Clinical parameters were obtained from medical records. The mutation of IDH1/2 and TP53 was analyzed by direct sequencing. O(6)-methylguanine methyltransferase gene (MGMT) gene promoter methylation status was determined by methylation-specific polymerase chain reaction. Detection of chromosome copy number changes of 1p, 7p (EGFR), 9p (CDKN2A), 10q (PTEN), and 19q was carried out by multiple ligation-dependent probe amplification. Patients were divided into two groups, mutated IDH1/2 and wild-type IDH1/2, for correlation with the factors analyzed.

RESULTS

In our series, as previously reported, IDH1/2 mutation was an independent prognostic marker for improved progression-free and overall survival (OS) (P < 0.0001 and P < 0.0001, respectively) in patients with grade III gliomas. Subgroup analysis found that incomplete resection, 7p gain, and TP53 mutation were independent prognostic factors of poor outcome in grade III glioma patients with mutated IDH1/2 (P = 0.0092, P = 0.015 and P = 0.026, respectively), while there were none in patients with wild-type IDH1/2.

CONCLUSIONS

IDH1/2 gene status was significantly associated with prognosis in grade III gliomas. Subgroup analysis found that poor prognostic factors existed even in patients with IDH1/2 mutation.

CD44v6 regulates growth of brain tumor stem cells partially through the AKT-mediated pathway

Identification of stem cell-like brain tumor cells (brain tumor stem-like cells; BTSC) has gained substantial attention by scientists and physicians. However, the mechanism of tumor initiation and proliferation is still poorly understood. CD44 is a cell surface protein linked to tumorigenesis in various cancers. In particular, one of its variant isoforms, CD44v6, is associated with several cancer types. To date its expression and function in BTSC is yet to be identified. Here, we demonstrate the presence and function of the variant form 6 of CD44 (CD44v6) in BTSC of a subset of glioblastoma multiforme (GBM). Patients with CD44^high GBM exhibited significantly poorer prognoses. Among various variant forms, CD44v6 was the only isoform that was detected in BTSC and its knockdown inhibited in vitro growth of BTSC from CD44^high GBM but not from CD44^low GBM. In contrast, this siRNA-mediated growth inhibition was not apparent in the matched GBM sample that does not possess stem-like properties. Stimulation with a CD44v6 ligand, osteopontin (OPN), increased expression of phosphorylated AKT in CD44^high GBM, but not in CD44^low GBM. Lastly, in a mouse spontaneous intracranial tumor model, CD44v6 was abundantly expressed by tumor precursors, in contrast to no detectable CD44v6 expression in normal neural precursors. Furthermore, overexpression of mouse CD44v6 or OPN, but not its dominant negative form, resulted in enhanced growth of the mouse tumor stem-like cells in vitro. Collectively, these data indicate that a subset of GBM expresses high CD44 in BTSC, and its growth may depend on CD44v6/AKTpathway.

Ruptured peripheral aneurysms in a collateral pathway associated with stenosis of a major cerebral artery: Report of two cases

Background

While hemodynamic stress can result in aneurysm formation, it rarely contributes to the development of peripheral aneurysms in collateral pathways. We report two patients with ruptured distal aneurysms in a collateral pathway associated with stenosis of a major cerebral artery.

Case Description

A 67-year-old man presented with intracerebral hemorrhage in the right frontal lobe. Digital subtraction angiography (DSA) revealed severe stenosis of the right middle cerebral artery and two aneurysms in the collateral pathway of the right anterior cerebral artery. The ruptured aneurysm was trapped and resected; histologically, it was a true saccular aneurysm. The unruptured aneurysm was clipped and the patient was discharged without additional neurological deficits. The second patient was a 73-year-old woman with subarachnoid hemorrhage. DSA revealed three arterial dilations. On the 7^th day of hospitalization, one of the aneurysms in a posterior inferior cerebellar artery–anterior inferior cerebellar artery anastomosis that functioned as a collateral pathway in the presence of severe basilar artery stenosis was found to be enlarged. It was treated by selective aneurysmal coil embolization with parent artery preservation. Her postoperative course was uneventful and she was discharged without any neurological deficits.

Conclusion

We document the successful treatment of two patients with ruptured aneurysms in the peripheral portion of a collateral pathway. We discuss the histology of peripheral aneurysms and present a review of the literature.

New insights into glioma classification based on isocitrate dehydrogenase 1 and 2 gene status

In glioma, mutations in the isocitrate dehydrogenase 1 and 2 (IDH1/2) genes have been receiving attention. IDH1/2 mutations are frequently found in grade II and III gliomas. These genetic alterations occur very early in gliomagenesis and strongly predict favorable outcome in patients with high-grade gliomas. Despite the evolution of studies on this topic, the underlying mechanism of the IDH1/2 mutations remains unknown. Here, we briefly review the current knowledge of IDH1/2 and discuss molecular diagnostics based on IDH1/2 gene status.

Imaging of hypoxic lesions in patients with gliomas by using positron emission tomography with 1-(2-[18F] fluoro-1-[hydroxymethyl]ethoxy)methyl-2-nitroimidazole, a new 18F-labeled 2-nitroimidazole analog

OBJECT

Assessment of hypoxic conditions in brain tumors is important for predicting tumor aggressiveness and treatment response. A new hypoxia imaging agent, 1-(2-[(18)F]fluoro-1-[hydroxymethyl]ethoxy)methyl-2-nitroimidazole (FRP-170), with higher image contrast and faster clearance than preexisting hypoxia tracers for PET, was used to visualize hypoxic tissues in 8 patients with glioma.

METHODS

The FRP-170 was injected and PET imaging was performed 2 hours later in 8 patients, including 3 with glioblastoma multiforme, 2 with oligodendroglioma, and 1 each with diffuse astrocytoma, anaplastic ganglioglioma, and recurrent anaplastic astrocytoma. All 8 patients also underwent MR imaging, and some patients underwent [(11)C]methionine or [(18)F]fluorodeoxyglucose PET, and proton MR spectroscopy for comparison. Tissues obtained at biopsy or radical resection were immunostained with hypoxia-inducible factor-1alpha (HIF-1alpha) antibody for the confirmation of hypoxia, except in the patient with recurrent anaplastic astrocytoma who was treated using Gamma Knife surgery.

RESULTS

The FRP-170 PET images showed marked uptake with upregulation of HIF-1alpha in the 3 glioblastomas multiforme, and moderate uptake in the recurrent anaplastic astrocytoma and one oligodendroglioma, but no uptake in the other tumors. The FRP-170 PET images showed positive correlation with HIF-1alpha immunoreactivity and some correlation with FDG PET and MR imaging enhancement, but no correlation with [(11)C]methionine PET. Imaging with FRP-170 PET seemed to be more sensitive for detecting hypoxia than identifying the lactate peak on proton MR spectroscopy.

CONCLUSIONS

Imaging with FRP-170 PET can visualize hypoxic lesions in patients with glioma, as confirmed by histological examination. This new method can assess tumor hypoxia preoperatively and noninvasively.

Hemorrhagic onset of pilocytic astrocytoma and pilomyxoid astrocytoma

The incidence of hemorrhagic onset in pilocytic astrocytoma and pilomyxoid astrocytoma, and the clinical and histological characteristics, were compared to other types of neuroepithelial tumors or nonhemorrhagic pilocytic astrocytoma by retrospective review of 445 consecutive neuroepithelial tumors treated at our institute. Hemorrhagic onset was observed in 4 of 35 (11.4%) patients with pilocytic astrocytoma and pilomyxoid astrocytoma, with higher incidence than in glioblastoma (3.9%), anaplastic oligodendroglioma (7.7%), and anaplastic ependymoma (7.1%). The hemorrhagic onset occurred in 2 patients with sporadic pilocytic astrocytoma, 1 with pilocytic astrocytoma associated with neurofibromatosis type 1, and 1 with pilomyxoid astrocytoma. There was no correlation between hemorrhagic onset and clinical features, including age, sex, tumor location, proliferative activity, or microvascular proliferation. Hemorrhagic onset of pilocytic astrocytoma and pilomyxoid astrocytoma is not as uncommon as was previously thought, so pilocytic astrocytoma or pilomyxoid astrocytoma should be considered in the differential diagnosis of patients with brain tumors manifesting as hemorrhagic onset.

Functional expression of human heme oxygenase-1 (HO-1) driven by HO-1 promoter in vitro and in vivo

We developed a retrovirus-mediated human heme oxygenase-1 (HO-1) gene expression system and assessed the impact of heme on the inducibility of the HO-1 gene in rat lung microvessel (RLMV) endothelial cells and in newborn Sprague-Dawley (SD) rats. Overexpression of the HO-1 gene driven by HO-1 promoter (HOP) resulted in an increase in HO-1 protein and HO activity by 4.8- and 1.3-fold, respectively, compared to the viral LTR promoter. The increased HO-1 gene expression was associated with the enhancement of CO production. In cells transduced by HOP-driven HO-1 gene, there was a decrease in basal cyclooxygenase (COX) activity as measured by PGE(2). The degree of HO-1 expression and, consequently, the levels of cellular heme were directly related to COX activity. Supplementation with heme markedly increased PGE(2) and cGMP synthesis. In all (6/6) of newborn SD rats injected with retrovirus LSN-HOP-HO-1, both HO-1 and neo(r) transcripts were expressed in tissues. We hypothesize that degree of HO-1 gene expression resulted in a differential rate of cellular heme-dependent enzyme gene expression, which may play a vital role in maintaining cellular homeostasis.

The use of epoxy patch grafts for the repair of experimentally-created diaphragmatic defects in dogs

Canine pericardium which had been treated with polyepoxy compounds (Denacol EX-313) was used as a patch graft for the correction of experimentally-created diaphragmatic defects in five dogs belonging to the same litter. Clinical, macroscopic and histological examinations were conducted every month up to five months after suturing of the patch graft. Clinical examination of the patch graft showed no apparent abnormalities. Macroscopic examination conducted during autopsy showed that the patch graft maintained adequate elasticity for five months after suturing, the surface of the patch graft was covered with a thin membrane and neovascularization was observed. Histological examination showed that the surface of the patch graft was covered with a thin membrane. Inflammatory tissue reactions were observed at one month, but gradually decreased from the second month onwards. In addition, the patch graft had excellent tissue affinity.