Provision of rapid and specific ex vivo diagnosis of central nervous system lymphoma from rodent xenograft biopsies by a fluorescent aptamer.

Objective: Differentiating central nervous system (CNS) lymphoma from other intracranial malignancies remains a clinical challenge in surgical neuro-oncology. Advances in clinical fluorescence imaging contrast agents and devices may mitigate this challenge. Aptamers are a class of nanomolecules engineered to bind cellular targets with antibody-like specificity in a fraction of the staining time.

Handheld confocal laser endomicroscopic imaging utilizing tumor-specific fluorescent labeling to identify experimental glioma cells .

Background: We have reported that handheld confocal laser endomicroscopy (CLE) can be used with various nonspecific fluorescent dyes to improve the microscopic identification of brain tumor and its boundaries. Here, we show that CLE can be used experimentally with tumor-specific fluorescent labeling to define glioma margins .

Methods: Thirteen rats underwent craniectomy and imaging 21 days after implantation with green fluorescent protein (GFP)-labeled U251 ( = 7) cells or epidermal growth factor receptor (EGFR) overexpressing F98 cells ( = 6).

The role of AKT isoforms in glioblastoma: AKT3 delays tumor progression.

The growth factor receptor/PI3K/AKT pathway is an important drug target in many cancers including Glioblastoma. AKT, a key node in the pathway, has 3 isoforms, AKT1, AKT2 and AKT3. Here we investigate their role in GBM.

Use of a conformational switching aptamer for rapid and specific ex vivo identification of central nervous system lymphoma in a xenograft model.

Improved tools for providing specific intraoperative diagnoses could improve patient care. In neurosurgery, intraoperatively differentiating non-operative lesions such as CNS B-cell lymphoma from operative lesions can be challenging, often necessitating immunohistochemical (IHC) procedures which require up to 24-48 hours. Here, we evaluate the feasibility of generating rapid ex vivo specific labeling using a novel lymphoma-specific fluorescent switchable aptamer.

AKT pathway genes define 5 prognostic subgroups in glioblastoma.

Activity of GFR/PI3K/AKT pathway inhibitors in glioblastoma clinical trials has not been robust. We hypothesized variations in the pathway between tumors contribute to poor response. We clustered GBM based on AKT pathway genes and discovered new subtypes then characterized their clinical and molecular features.

Molecular interactions of ErbB1 (EGFR) and integrin-β1 in astrocytoma frozen sections predict clinical outcome and correlate with Akt-mediated in vitro radioresistance.

Introduction: Treatment of astrocytoma is frequently hampered by radioresistance of the tumor. In addition to overexpression of ErbB1/EGFR, functional crosstalk between receptor tyrosine kinases and cell adhesion molecules may also contribute to therapy resistance.

Methods: Acceptor photobleaching FRET was implemented on frozen sections of clinical astrocytoma to check the role of ErbB1-integrin-β1 interaction.

Intraoperative fluorescent imaging of intracranial tumors: a review.

A review of fluorescent imaging for intracranial neoplasms is presented. Complete resection of brain cancer is seldom possible because of the goal to preserve brain tissue and the inability to visualize individual infiltrative tumor cells. Verification of histology and identification of tumor invasion in macroscopically normal-appearing brain tissue determine prognosis after resection of malignant gliomas.

DNA copy number alterations in central primitive neuroectodermal tumors and tumors of the pineal region: an international individual patient data meta-analysis.

Little is known about frequency, association with clinical characteristics, and prognostic impact of DNA copy number alterations (CNA) on survival in central primitive neuroectodermal tumors (CNS-PNET) and tumors of the pineal region. Searches of MEDLINE, Pubmed, and EMBASE--after the original description of comparative genomic hybridization in 1992 and July 2010--identified 15 case series of patients with CNS-PNET and tumors of the pineal region whose tumors were investigated for genome-wide CNA. One additional case study was identified from contact with experts.

Reevaluating the imaging definition of tumor progression: perfusion MRI quantifies recurrent glioblastoma tumor fraction, pseudoprogression, and radiation necrosis to predict survival.

Introduction: Contrast-enhanced MRI (CE-MRI) represents the current mainstay for monitoring treatment response in glioblastoma multiforme (GBM), based on the premise that enlarging lesions reflect increasing tumor burden, treatment failure, and poor prognosis. Unfortunately, irradiating such tumors can induce changes in CE-MRI that mimic tumor recurrence, so called post treatment radiation effect (PTRE), and in fact, both PTRE and tumor re-growth can occur together. Because PTRE represents treatment success, the relative histologic fraction of tumor growth versus PTRE affects survival.

Pituicytoma: characterization of a unique neoplasm by histology, immunohistochemistry, ultrastructure, and array-based comparative genomic hybridization.

The pituicytoma is a rare neoplasm whose histogenesis is debated partly because of the diversity of tissue types present in the sellar region. In this article we illustrate the characteristic histologic, immunohistologic, and ultrastructural features of this unique neoplasm. Furthermore, we use array-based comparative genomic hybridization to demonstrate a unique pattern of genomic copy number aberrations in pituicytomas.

A multigene predictor of outcome in glioblastoma.

Only a subset of patients with newly diagnosed glioblastoma (GBM) exhibit a response to standard therapy. To date, a biomarker panel with predictive power to distinguish treatment sensitive from treatment refractory GBM tumors does not exist. An analysis was performed using GBM microarray data from 4 independent data sets.

Amplifying small amounts of tumor DNA allows detection of DNA copy number abberations with array-CGH.

Array comparative genomic hybridization (aCGH) is a powerful tool to detect relative DNA copy number at a resolution limited only by the coverage of bacterial artificial chromosomes (BACs) used to print the genomic array. The amount of DNA needed to perform a reliable aCGH analysis has been a limiting factor, especially on minute tissue samples where limited DNA is available. Here we report a simple, highly sensitive and reliable aCGH method to analyze samples of no more than 1 ng genomic DNA.

Functional inactivation of the KLF6 tumor suppressor gene by loss of heterozygosity and increased alternative splicing in glioblastoma.

Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor and possesses a high incidence of 10p loss. The KLF6 (Kruppel-like transcription factor) tumor suppressor gene on 10p15 is inactivated by loss of heterozygosity (LOH) and/or somatic mutation in a number of human cancers and forced expression of KLF6 in GBM lines inhibits their growth and transformation. In addition, increased expression of its alternatively spliced, cytoplasmic isoform KLF6-SV1 has now been shown to play a role in cancer pathogenesis.

Contribution of Notch signaling activation to human glioblastoma multiforme.

Object: Because activation of Notch receptors has been suggested to be critical for Ras-mediated transformation, and because many gliomas exhibit deregulated Ras signaling, the authors measured Notch levels and activation in primary samples and cell lines derived from glioblastoma multiforme (GBM) as well as the contribution of Notch pathway activation to astrocytic transformation and growth.

Methods: Western blot analysis of Notch 1 expression and activation showed that Notch 1 protein was overexpressed and/or activated in Ras-transformed astrocytes, in three of four GBM cell lines, and in four of five primary GBM samples. Expansion of these studies to assess mRNA expression of components of the Notch signaling pathway by cDNA expression array showed that cDNAs encoding components of the Notch signaling pathway, including the Notch ligand Jagged-1, Notch 3, and the downstream targets of Notch (HES1 and HES2), were also overexpressed relative to non-neoplastic brain controls in 23, 71, and 51% of 35 primary GBMs, respectively.

Identification of IGF2 signaling through phosphoinositide-3-kinase regulatory subunit 3 as a growth-promoting axis in glioblastoma.

Amplification or overexpression of growth factor receptors is a frequent occurrence in malignant gliomas. Using both expression profiling and in situ hybridization, we identified insulin-like growth factor 2 (IGF2) as a marker for a subset of glioblastomas (GBMs) that lack amplification or overexpression of EGF receptor. Among 165 primary high-grade astrocytomas, 13% of grade IV tumors and 2% of grade III tumors expressed IGF2 mRNA levels >50-fold the sample population median.

Genetic aberrations in gliomatosis cerebri.

Objective: Identifying the genetic alterations in gliomatosis cerebri (GC) may yield clinically useful prognostic markers and provide clues as to whether GC represents a distinct pathological entity or is an extreme form of diffusely infiltrative glioma.

Methods: Clinical histories, treatment histories, magnetic resonance imaging, and pathological analysis of patients with GC treated at either the University of California San Francisco or the Mayo Clinic were reviewed. Degenerate oligonucleotide-primed polymerase chain reaction was performed on biopsy samples of GC.

Angiogenesis-independent tumor growth mediated by stem-like cancer cells.

In this work, highly infiltrative brain tumors with a stem-like phenotype were established by xenotransplantation of human brain tumors in immunodeficient nude rats. These tumors coopted the host vasculature and presented as an aggressive disease without signs of angiogenesis. The malignant cells expressed neural stem cell markers, showed a migratory behavior similar to normal human neural stem cells, and gave rise to tumors in vivo after regrafting.

A genetic strategy to overcome the senescence of primary meningioma cell cultures.

Even though meningiomas are the second most common brain tumor in adults, little is known about the molecular basis of their growth and development. The lack of suitable cell culture model systems is an impediment to this understanding. Most studies on meningiomas rely on primary, early passage cell lines that eventually senesce or a few established cell lines that have been derived from aggressive variants of meningiomas.

Molecular subclasses of high-grade glioma predict prognosis, delineate a pattern of disease progression, and resemble stages in neurogenesis.

Previously undescribed prognostic subclasses of high-grade astrocytoma are identified and discovered to resemble stages in neurogenesis. One tumor class displaying neuronal lineage markers shows longer survival, while two tumor classes enriched for neural stem cell markers display equally short survival. Poor prognosis subclasses exhibit markers either of proliferation or of angiogenesis and mesenchyme.

Biphasic calcium response of platelet-derived growth factor stimulated glioblastoma cells is a function of cell confluence.

Background: Previous reports have linked the spiking or two-phased character of calcium transients evoked by platelet-derived growth factor (PDGF) to the position of cells in the cell cycle without regard to cell-cell contact and communication. Because cell confluence can regulate growth factor receptor expression and dephosphorylation, we investigated the effect of cell culture confluence and cell cycle on calcium responses of PDGF-BB-stimulated A172 glioblastoma cells.

Methods: Digital imaging cytometry was used to correlate the peak and duration of calcium response with bromodeoxyuridine positivity and DNA content and with culture confluence on a cell-by-cell basis.

Chromosome transfer experiments link regions on chromosome 7 to radiation resistance in human glioblastoma multiforme.

Glioblastoma multiforme (GM) is the most lethal form of brain tumor, with a median survival of approximately 1 year. Treatment options are limited. Radiation therapy is a common form of treatment, but many tumors are resistant.

Isochromosome 17q is a negative prognostic factor in poor-risk childhood medulloblastoma patients.

Background: Medulloblastomas are the most common primary malignant childhood intracranial neoplasms. Patients are currently sorted into three risk groups based on clinical criteria: standard, poor, and infant (<18 months old). We hypothesized that genetic copy number aberrations (CNA) predict prognosis and would provide improved criteria for predicting outcome.

Molecular cytogenetic analysis of chromosomes 1 and 19 in glioma cell lines.

Deletions of chromosome 1p and 19q arms are frequent genetic abnormalities in primary human gliomas and are especially common in oligodendrogliomas. However, the chromosome 1p and 19q status of many glioma cell lines has not been established. Using homozygosity mapping, fluorescence in situ hybridization (FISH), and comparative genomic hybridization to arrayed BAC (CGHa), we screened 17 glioma cell lines for chromosome 1 and 19 deletions.

Array comparative genomic hybridization identifies genetic subgroups in grade 4 human astrocytoma.

Alterations of DNA copy number are believed to be important indicators of tumor progression in human astrocytoma. We used an array of bacterial artificial chromosomes to map relative DNA copy number in 50 primary glioblastoma multiforme tumors at approximately 1.4-Mb resolution.

Integrated array-comparative genomic hybridization and expression array profiles identify clinically relevant molecular subtypes of glioblastoma.

Glioblastoma, the most aggressive primary brain tumor in humans, exhibits a large degree of molecular heterogeneity. Understanding the molecular pathology of a tumor and its linkage to behavior is an important foundation for developing and evaluating approaches to clinical management. Here we integrate array-comparative genomic hybridization and array-based gene expression profiles to identify relationships between DNA copy number aberrations, gene expression alterations, and survival in 34 patients with glioblastoma.