Yugo Kishida

Benefits of interferon-β and temozolomide combination therapy for newly diagnosed primary glioblastoma with the unmethylated MGMT promoter: A multicenter study.

The aim of the current study was to catalog genomic and epigenomic abnormalities in newly diagnosed glioblastoma patients and determine the correlation among clinical, genetic, and epigenetic profiles and clinical outcome.

The global DNA methylation surrogate LINE-1 methylation is correlated with MGMT promoter methylation and is a better prognostic factor for glioma.

Gliomas are the most frequently occurring primary brain tumor in the central nervous system of adults. Glioblastoma multiformes (GBMs, WHO grade 4) have a dismal prognosis despite the use of the alkylating agent, temozolomide (TMZ), and even low grade gliomas (LGGs, WHO grade 2) eventually transform to malignant secondary GBMs. Although GBM patients benefit from promoter hypermethylation of the O 6-methylguanine-DNA methyltransferase (MGMT) that is the main determinant of resistance to TMZ, recent studies suggested that MGMT promoter methylation is of prognostic as well as predictive significance for the efficacy of TMZ. Glioma-CpG island methylator phenotype (G-CIMP) in the global genome was shown to be a significant predictor of improved survival in patients with GBM. Collectively, we hypothesized that MGMT promoter methylation might reflect global DNA methylation. Additionally in LGGs, the significance of MGMT promoter methylation is still undetermined. In the current study, we aimed to determine the correlation between clinical, genetic, and epigenetic profiles including LINE-1 and different cancer-related genes and the clinical outcome in newly diagnosed 57 LGG and 54 GBM patients. Here, we demonstrated that (1) IDH1/2 mutation is closely correlated with MGMT promoter methylation and 1p/19q codeletion in LGGs, (2) LINE-1 methylation levels in primary and secondary GBMs are lower than those in LGGs and normal brain tissues, (3) LINE-1 methylation is proportional to MGMT promoter methylation in gliomas, and (4) higher LINE-1 methylation is a favorable prognostic factor in primary GBMs, even compared to MGMT promoter methylation. As a global DNA methylation marker, LINE-1 may be a promising marker in gliomas.

Epigenetic subclassification of meningiomas based on genome-wide DNA methylation analyses

Meningiomas are among the most common intracranial tumors and are mostly curable by surgical resection. However, some populations of meningiomas with benign histological profiles show malignant behavior. The reasons for this inconsistency are yet to be ascertained, and novel diagnostic criteria other than the histological one are urgently needed. The aim of the present study is to subclassify meningiomas from the viewpoint of gene methylation and to determine the subgroup with malignant characteristics. Thirty meningiomas were analyzed using microarrays for 6157 genes and were classified into three clusters on the basis of their methylation status; these were found to be independent of the histological grading. One of the clusters showed a high frequency of recurrence, with a marked accumulation of methylation in a subset of genes. We hypothesized that the aggressive meningiomas universally share characteristic methylation in certain genes; therefore, we chose the genes that strongly contributed to cluster formation. The quantified methylation values of five chosen genes (HOXA6, HOXA9, PENK, UPK3A and IGF2BP1) agreed well with microarray findings, and a scoring system consisting of the five genes significantly correlated with a high frequency of recurrence in an additional validation set of 32 patients. Of particular note is that three cases with malignant transformation already showed hypermethylation at histologically benign stage. In conclusion, a subgroup of meningiomas is characterized by aberrant hypermethylation of the subset of genes in the early stage of tumorigenesis, and our findings highlight the possibility of speculating potential malignancy of meningiomas by assessing methylation status.

Correlation between quantified promoter methylation and enzymatic activity of O6-methylguanine-DNA methyltransferase in glioblastomas

The DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT, AGT) is a determinant of the resistance of tumor cells to alkylating anticancer agents that target the O6 position of guanine. MGMT promoter methylation in tumors is regarded as the most common predictor of the responsiveness of glioblastoma to alkylating agents. However, MGMT promoter methylation status has been investigated mainly by methylation-specific PCR, which is a qualitative and subjective assay. In addition, the actual enzymatic activities associated with the methylation status of MGMT have not been explored. In the present study, MGMT promoter methylation in glioblastomas was quantified by bisulfite pyrosequencing, and its correlation with enzymatic activity was determined using a novel quantitative assay for studying the functional activity of MGMT. MGMT enzymatic activity was assessed using fluorometrically labeled oligonucleotide substrates containing MGMT-specific DNA lesions and capillary electrophoresis to detect and quantify these lesions. In comparison with existing traditional assays, this assay was equally sensitive but less time consuming and easier to perform. MGMT promoter methylation was assessed in 41 glioblastomas by bisulfite pyrosequencing, and five samples with different values were chosen for comparison with enzymatic assays. Bisulfite pyrosequencing using primers designed to work in the upstream promoter regions of MGMT demonstrated high quantitative capability and reproducibility in triplicate measurements. In comparative studies, MGMT promoter methylation values obtained by bisulfite pyrosequencing were inversely proportional to the measured enzymatic activity. The present results indicate that the quantification of MGMT methylation by bisulfite pyrosequencing represents its enzymatic activity and thus, its therapeutic responsiveness to alkylating agents.

Magnetically guided 3-dimensional virtual neuronavigation for neuroendoscopic surgery: technique and clinical experience.

OBJECTIVE The authors have developed a novel intraoperative neuronavigation with 3-dimensional (3D) virtual images, a 3D virtual navigation system, for neuroendoscopic surgery. The present study describes this technique and clinical experience with the system. METHODS Preoperative imaging data sets were transferred to a personal computer to construct virtual endoscopic views with image segmentation software. An electromagnetic tracker was used to acquire the position and orientation of the tip of the neuroendo-scope. Virtual endoscopic images were interlinked to an electromagnetic tracking system and demonstrated on the navigation display in real time. Accuracy and efficacy of the 3D virtual navigation system were evaluated in a phantom test and on 5 consecutive patients undergoing neuroendoscopic surgery. RESULTS Virtual navigation views were consistent with actual endoscopic views and trajectory in both phantom testing and clinical neuroendoscopic surgery. Anatomic structures that can affect surgical approaches were adequately predicted with the virtual navigation system. The virtual semitransparent view contributed to a clear understanding of spatial relationships between surgical targets and surrounding structures. Surgical procedures in all patients were performed while confirming with virtual navigation. In neurosurgery with a flexible neuroscope, virtual navigation also demonstrated anatomic structures in real time. CONCLUSION The interactive method of intraoperative visualization influenced the decision-making process during surgery and provided useful assistance in identifying safe approaches for neuroendoscopic surgery. The magnetically guided navigation system enabled navigation of surgical targets in both rigid and flexible endoscopic surgeries.

Skull base invasive low-grade meningiomas, a distinct genetic subgroup: A microarray gene expression profile analysis.

Introduction Meningioma is the most common adult primary brain tumor originating from meningeal coverings of the brain and spinal cord. Commonly, World Health Organization (WHO) grade-I meningiomas are slowly growing and surgically curative, some present with clinically aggressive behavior, invading the skull base bone and soft tissues by extending into the extracranial spaces. Methods To detect the genetic background of the Skull Base Invasive Low-grade Meningioma (SBILM), we conducted a comprehensive analysis of gene expression was conducted on 32 meningioma samples. Results The cluster analysis of the gene expression profile demonstrated a distinctive clustering pattern of the SBILM. Based on the clinical behavior and the microarray findings, they might be a distinct subgroup of meningiomas. Conclusion Further studies on characterization of genes specifically expressed by the SBILM could lead to the development of diagnostic tools, differentiating it from other WHO grade-I meningiomas and assist in the appropriate management and follow-up strategy, and open the door for development of pharmacological therapies.

Neuroendoscopic Cylinder Surgery and 5-Aminolevulinic Acid Photodynamic Diagnosis of Deep-Seated Intracranial Lesions

BACKGROUND Microscopic detection of intracranial brain tumors with 5-aminolevulinic acid (5-ALA) has proven extremely useful, and reports the use of 5-ALA have recently increased. However, few reports have described 5-ALA photodynamic diagnosis (PDD) using a neuroendoscope. We performed neuroendoscopic 5-ALA PDD for various brain lesions and present a procedure using only a neuroendoscope. METHODS We describe the diagnosis of 20 intracranial brain lesion cases with a 5-ALA-guided fluorescence endoscope. A light-emitting diode that emitted either white light or 400- to 410-nm violet light was attached to a neuroendoscope. We performed cylinder surgery with a transparent sheath under observation with a rigid neuroendoscope. RESULTS Neuroendoscopic biopsies were performed in 11 patients, and resections were performed in 9 patients. All lesions were observed with a neuroendoscope under sequential white light and violet light. We confirmed the presence of a red fluorescent lesion under violet light in 15 patients, including 4 of 5 glioblastoma cases (80%); 1 of 2 anaplastic astrocytoma cases (50%); 4 of 5 diffuse large B cell lymphoma cases (80%); 2 of 2 metastatic brain tumors; 1 of 1 case each of diffuse astrocytoma, pilocytic astrocytoma, inflammatory change, and germinoma (100%); and no cases of anaplastic ependymoma or cysticercosis. Pretargeted lesions were accurately harvested from all biopsy specimens. Gross total resection was achieved in 5 of 9 patients using a resection procedure. CONCLUSIONS Our described method offers a promising technique for achieving precise brain tumor biopsies and safe resection.

A case of orbital apex syndrome due to aspergillus infection that avoided loss of visual acuity by optic canal decompression

A 71-year-old woman was admitted to our hospital complaining of left orbital pain, headache, diplopia and left-sided ptosis, which she had suffered for two months. On examination, the patient had loss of visual acuity, left-sided ptosis, lateral gaze disturbance, and was diagnosed as having left orbital apex syndrome. An abnormal signal to the left orbital cone was detected on MRI. Serum β-D-glucan was increased, and serum Aspergillus antigen and antibody were both positive. Although antifungal drugs (voriconazole and liposomal amphotericin B) were administered, the symptoms deteriorated. The patient then underwent optic nerve decompression surgery and was treated with intravenous methylprednisolone, which gradually improved the patients symptoms, Aspergillus hyphae were confirmed by pathological examination. To obtain good prognosis for patients with orbital apex syndrome associated with Aspergillus infection, optic nerve decompression surgery should be considered.