Desmoplastic Medulloblastoma Research Articles

P75NTR induces apoptosis in medulloblastoma cells

The classic medulloblastoma (CMB) and the desmoplastic medulloblastoma (DMB) subtypes represent the major medulloblastoma variants. In contrast to CMB, DMB display high levels of the low-affinity nerve growth factor receptor p75(NTR) . Given the reports of a better clinical course of DMB, we hypothesized that p75(NTR) might act as a tumor suppressor in medulloblastomas. In a large set of medulloblastomas, p75(NTR) was screened for mutations, and its mRNA expression and the DNA methylation status of its 5'-region were assessed. p75(NTR) immunostainings were performed in wild-type murine cerebella and medulloblastomas arising in patched heterozygous mice, and murine cerebellar granule cell precursors (GCP) were analyzed in vitro. Medulloblastoma cells engineered to express p75(NTR) were characterized flow cytometrically and morphologically. One CMB displayed a mutation of the p75(NTR) coding sequence. p75(NTR) mRNA levels clearly delineated DMB and CMB; however, CpG island hypermethylation was excluded as the cause of low p75(NTR) expression in CMB. Sonic Hedgehog-treated GCP showed elevated p75(NTR) expression, and strong expression of p75(NTR) was detected in the external granule cell layer of wild-type mice and in murine ptc(±) medulloblastomas. CMB cells overexpressing p75(NTR) displayed a significant increase in apoptosis. In summary, our data link activated Hedgehog signaling in DMB with p75(NTR) expression and characterize p75(NTR) as a biologically relevant inductor of apoptosis in MB.

Nervous system tumors: Medulloblastoma

Belongs to the primitive neurectodermal tumours (PNET): highly malignant embryonal tumours of the CNS with predominant neuronal differentiation. Several variants medulloblastoma are recognized in the OMS classification: Classic medulloblastoma composed of densely jacked round-cells with round to oval hyperchromatic nuclei. Desmoplastic medulloblastoma represents a variant with abundant reticulin and collagen. Large cell medulloblastoma is a rare variant composed of cells with large round nuclei.

Histology predicts a favorable outcome in young children with desmoplastic medulloblastoma

Contemporary therapy for medulloblastoma results in adverse neurocognitive effects on young children, particularly those under the age of 3. Stratification of patients by risk group may allow toxic treatment to be avoided. Seventy-six patients diagnosed with medulloblastoma and enrolled on CCG-9921 underwent central review of pathology, and histologic subtype was designated as desmoplastic or nondesmoplastic. Nonparametric event-free survival (EFS) and survival (OS) curves were computed using the product limit (Kaplan-Meier) estimates, and the log-rank test was used to compare survival according to histologic subtype. Patients with desmoplastic medulloblastoma experienced a favorable EFS of 77% ± 9% and OS of 85% ± 8% compared with EFS of 17% ± 5% and OS of 29% ± 6% for patients with tumors in the nondesmoplastic group (P < .0001 for both EFS and OS comparisons). Patients without disease progression did not receive radiation therapy. Children less than 3 with desmoplastic histology of medulloblastoma represent a lower-risk group for whom reduction of therapy, including elimination of radiation therapy, is an appropriate strategy.

Magnetic resonance spectroscopy findings in non-enhancing desmoplastic medulloblastoma

Medulloblasoma is a common posterior fossa tumor seen in children and presents with some typical features like midline vermian location and fairly homogeneous enhancment. Desmoplastic variety of medulloblastoma is usually seen in the adults and is known to show some atypical features like lateral cerebellar location, variable enhancement, and early meningeal infilteration. Therefore medulloblastoma should always be considered in differential diagnosis of posterior fossa mass in adults even when typical imaging findings are not that of medulloblastoma. Enhancement pattern can be variable in these tumors varying from mild to striking. Occasionally, totally non-enhancing tumors are encountered, which can cause further diagnostic confusion. We describe the magnetic resonance (MR) and MR spectroscopy findings in a case of midline vermian mass, which did not show any enhancement on post-contrast images, and was subsequently proven to be desmoplastic medulloblastoma. On MR spectroscopy, the mass showed elevated choline peak consistent with mitotic lesion. No significant lipid lactate leak was seen, which is also consistent with the ususally homogeneous nature of these tumors. Moreover, it displayed taurine peak at 3.4 ppm which is considered fairly specific for medulloblastoma. Therefore, MR spectroscopy findings can be helpful in the diagnosis of medulloblastoma in adults when MR imaging findings can be nonspecific.

Heterogeneity of familial medulloblastoma and contribution of germline PTCH1 and SUFU mutations to sporadic medulloblastoma

PTCH1 and SUFU are both regulators of the sonic hedgehog signalling pathway. Germline inactivating mutations in both genes are associated with multisystem phenotypes including medulloblastoma. Somatic inactivating mutations in PTCH1 and SUFU each occur in approximately 10% of medulloblastomas. Recently, SUFU mutations were reported in familial medulloblastoma pedigrees without additional phenotypic features. We sought to further investigate the contribution of germline PTCH1 and SUFU mutations to familial and sporadic medulloblastoma. We performed full-gene mutational analysis of both PTCH1 and SUFU in three familial medulloblastoma pedigrees and 83 individuals with sporadic non-familial medulloblastoma. We identified no mutations in PTCH1 or SUFU in the three familial medulloblastoma pedigrees. We identified no PTCH1 mutations and two SUFU mutations that cause premature protein truncating in the series of sporadic non-familial medulloblastomas. The SUFU mutations were identified in two of the 16 individuals with desmoplastic medulloblastomas. These data indicate that familial medulloblastoma is a genetically heterogeneous disorder with at least one further susceptibility gene to be discovered. Furthermore, although both PTCH1 and SUFU play a key role in the sonic hedgehog signalling pathway, PTCH1 does not make an appreciable contribution to non-familial sporadic medulloblastoma, whereas inactivating germline mutations of SUFU cause ~2-3% of sporadic medulloblastomas and>10% of desmoplastic medulloblastomas.

Outcome and prognostic factors of desmoplastic medulloblastoma treated within a multidisciplinary treatment concept

BackgroundDesmoplasia in medulloblastoma is often diagnosed in adult patients and was repeatedly associated with improved results. Today, all medulloblastoma patients receive intensive multimodal treatment including surgery, radiotherapy and chemotherapy. This study was set up to investigate treatment outcome and prognostic factors after radiation therapy in patients with desmoplastic medulloblastomas.MethodsTwenty patients treated for desmoplastic medulloblastoma in the Department of Radiation Oncology at the University of Heidelberg between 1984 and 2007 were included. Data were collected retrospectively. Tumor resection was performed in all patients. All patients underwent postsurgical radiotherapy (RT). Two patients underwent whole brain radiotherapy (WBRT), and 18 patients received craniospinal irradiation (CSI). In all patients, an additional boost was delivered to the posterior fossa. The median dose to the whole brain and the craniospinal axis was 35.2 Gray (Gy), and 54.4 Gy to the posterior fossa. Fourteen patients received chemotherapy, including seven who were treated with combined radiochemotherapy and twelve who received adjuvant chemotherapy. Statistical analysis was performed using the log-rank test and the Kaplan-Meier method.ResultsMedian follow-up was 59 months. Overall (OS), local (LPFS) and distant progression-free survival (DPFS) was 80%, 71.2%, and 83.3% at 60 months. Patients who suffered from local or distant relapses had significantly worse outcome. Five patients died from recurrent medulloblastoma. Treatment-associated toxicity was acceptable.ConclusionsMultimodal approaches with surgical resection followed by chemoirradiation achieved high response rates with long OS in desmoplastic medulloblastoma patients. Staging parameters expected to predict for poor prognosis did not significantly influence outcome. However, success of any first line regimen had strong impact on disease control, and remission was achieved in no patient with relapsing disease. Multimodal concepts must be evaluated in further clinical trials.

Value and Limitations of Diffusion-Weighted Imaging in Grading and Diagnosis of Pediatric Posterior Fossa Tumors: Fig 1.

DWI reportedly accurately differentiates pediatric posterior fossa tumors, but anecdotal experience suggests limitations. In 3 years, medulloblastoma and JPA were differentiated by DWI alone in 23/26 cases (88%). Ependymoma (n = 5) could not be reliably differentiated from medulloblastoma or JPA. A trend toward increased diffusion restriction in higher grade tumors (1/14 grade I, 7%; 9/12 grade IV, 75%) had too much overlap to predict the grade of individual cases. The overlap in ADC between tumor types appeared partly due to technical factors (in small, heterogeneous, calcific, or hemorrhagic tumors) but also likely reflected true histologic variability, given that our 3 overlap cases included a desmoplastic medulloblastoma, an anaplastic ependymoma, and a JPA with restricted diffusion in its nodule. Simple structural features (macrocystic tumor, location off midline) aided in distinguishing JPA from the other tumors in these cases.

Abstract 763: A systematic screening identify new drugs impairing medulloblastoma tumorigenesis

Abstract Medulloblastoma (MB) is the most common Central nervous system (CNS) neoplasia accounting for 25% of all childhood brain tumors. The Wnt, Sonic and Notch developmental cascades all regulate CNS cell dynamics, and are mutationally activated in a subset of MBs. So far the main limitation of the current treatment of MB is the lack of drug specificity, we aim to identify new specific impairment pathway drugs to offer new therapeutic tools in order to improve the clinical management of this neoplasia. The Wnt signaling pathway ends in the regulation of the levels of β-catenin which accumulates in the nucleus and interacts with the LEF/TCF family of transcription factors; in the absence of Wnt stimulation, β-catenin is phosphorylated by several kinases, as a complex comprising GSK3-β, Axin and APC, and it is targeted for degradation in the cytoplasm via the ubiquitin-proteasome pathway. Wnt activation includes key regulators of proliferation, among which c-Myc and cyclin D1 play a crucial role. We screened a drug library including almost 1200 compounds which are not well characterized on their activity against cancer cells. The library contains a repository of Natural Products, that derive from marine and plant sources collected worldwide, and a Synthetic library Products. We tested the efficacy of the Natural Products to interfere with Wnt pathway, using the TOP/FOP luciferase assay. From this large screening, we focused our attention on three natural compounds (Cantharidin, Parthenolide, Homoharringotnine) which positively inhibit Wnt pathway in three independent MB cell lines: Daoy (a desmoplastic medulloblastoma), ONS-76 and UW288(classic medulloblastoma cell lines). We determined their ability to turn-off Wnt signaling by western blotting detecting β-catenin activated protein and by RT-PCR for controlling of mRNA levels of WNT target genes. Cantharidin (CTD) has an anticancer activity in leukemic cells and melanoma cells, but it is still to be identified which is the basis of its mechanism. CTD is a potent inhibitor of phosphatase PP1 and PP2A which play a positive role in regulating Wnt signalling since it dephosphorylates AXIN, by impairing APC complex. We screened CTD as the most effective drug to inhibit Wnt pathway in MB cells. By immunofluorescence, we observed that the nuclear amount of β-catenin was found reduced when the cells were exposed to CTD. We found its effectiveness in vitro and in vivo on tumor growth assays in nude and strengthen those with additional orthotopic cerebellum xenografs assays to further assign its molecular mechanism of action in MB thus suggesting its use for future therapeutic applications in mouse MB genetic models. Altogether these results are suggesting a new therapeutic strategy to treat MB to be further applied to other solid tumors which are mainly Wnt driven. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 763.

Radiation-induced cerebellar high-grade glioma accompanied by meningioma and cavernoma 29 years after the treatment of medulloblastoma: a case report

Here, we report the case of a patient with cerebellar high-grade glioma that developed after the patient underwent treatment for medulloblastoma. A 34-year-old man visited our hospital with complaints of dizziness and truncal ataxia. Magnetic resonance image showed a cerebellar tumor with multiple cavernomas and two lesions that were suspected to be meningiomas. The cerebellar tumor was surgically removed. According to pathological examination, the tumor was a high-grade glioma that was positive for methylated O-6-methylguanine-DNA methyltransferase promoter. In the past, he had received radiotherapy at the age of 5, after which he was operated for desmoplastic medulloblastoma in his right cerebellar hemisphere. Seven years after the initial therapy, cavernoma-induced intracerebral hemorrhage of the right temporal lobe was noted. To our knowledge, this is the first case of radiation-induced double intracranial tumors accompanied by symptomatic cavernoma.

Pediatric brain tumors: genetics and clinical outcome

In this paper the authors' goal was to investigate the genetic characteristics of primary brain tumors in children and determine their influence on clinical outcome. The authors performed high-resolution comparative genomic hybridization studies in 14 low-grade and 12 high-grade brain neoplasms in 26 children who underwent surgery between 2005 and 2007. Complex comparative genomic hybridization alterations were observed in 2 (14.3%) of the 14 lowgrade lesions and in 8 (66.6%) of the 12 high-grade lesions. High-level amplifications of DNA were detected in 3 cases, namely in a desmoplastic medulloblastoma where a c-Myc amplification was found. Gains of 1q were detected in 2 low-grade and 6 high-grade lesions that were classified as ependymomas, astrocytomas, oligodendrogliomas, oligoastrocytomas, and gangliogliomas. When the authors correlated genetics with outcome, they noted that among the low-grade neoplasms only the 2 patients who presented with complex comparative genomic hybridization alterations had to undergo reoperation because of recurrent disease. The patient with c-Myc amplification died of progressive disease. Gains of 1q were only observed in tumor cases with progressive disease. Complex genetic alterations are indicative of a less favorable outcome in low-grade tumors. In these cases, closer follow-up should be pursued. The authors corroborate that c-Myc amplification is a marker of poor prognosis in medulloblastomas. In this study, they were able to verify that a 1q gain correlates with a poor clinical outcome, independent of tumor grade and histological type. The authors propose that it may be considered a common marker of poor prognosis in these neoplasms.

Expression of the Brain Transcription Factor OTX1 Occurs in a Subset of Normal Germinal-Center B Cells and in Aggressive Non-Hodgkin Lymphoma

The roles in brain development. Previous studies have shown the association between OTX2 and OTX1 with anaplastic and desmoplastic medulloblastomas, respectively. Here, we investigated OTX1 and OTX2 expression in Non-Hodgkin Lymphoma (NHL) and multiple myeloma. A combination of semiquantitative RT-PCR, Western blot, and immunohistochemical analyses was used to measure OTX1 and OTX2 levels in normal lymphoid tissues and in 184 tumor specimens representative of various forms of NHL and multiple myeloma. OTX1 expression was activated in 94% of diffuse large B-cell lymphomas, in all Burkitt lymphomas, and in 90% of high-grade follicular lymphomas. OTX1 was undetectable in precursor-B lymphoblastic lymphoma, chronic lymphocytic leukemia, and in most marginal zone and mantle cell lymphomas and multiple myeloma. OTX2 was undetectable in all analyzed malignancies. Analysis of OTX1 expression in normal lymphoid tissues identified a subset of resting germinal center (GC) B cells lacking PAX5 and BCL6 and expressing cytoplasmic IgG and syndecan. About 50% of OTX1(+) GC B cells co-expressed CD10 and CD20. This study identifies OTX1 as a molecular marker for high-grade GC-derived NHL and suggests an involvement of this transcription factor in B-cell lymphomagenesis. Furthermore, OTX1 expression in a subset of normal GC B cells carrying plasma cell markers suggests its possible contribution to terminal B-cell differentiation.

Classic and desmoplastic medulloblastoma: Complete case reports and characterizations of two new cell lines

Medulloblastoma (MB) is the most common type of brain tumor affecting children. These tumors are a significant cause of childhood mortality and morbidity, and more effective and less invasive treatment options are urgently required. To achieve these aims, it will be critical to develop a more comprehensive understanding of the molecular pathogenesis of MB. At present, there are relatively few well-characterized MB cell lines available to the research community for the study of MB molecular and cellular biology. Here we present the case reports of two children diagnosed with classic and desmoplastic MB, and describe the characteristics of two new MB cell lines derived from these individuals. A number of genes encoding components of the sonic hedgehog (SHH) and WNT pathways were up-regulated in the desmoplastic relative to the classic MB cell line consistent with aberrant activation of these pathways in desmoplastic MB. These cell lines represent an additional resource for the analysis of diverse aspects of MB biology.

Medulloblastoma Variants: Age-Dependent Occurrence and Relation to Gorlin Syndrome—A New Clinical Perspective

We aimed to test the hypothesis that medulloblastoma (MB) variants show a different age distribution and clinical behavior reflecting their specific biology, and that MB occurring at very young age is associated with cancer predisposition syndromes such as Gorlin syndrome (GS). We investigated the frequency, age distribution, location, response to treatment, outcome, and association with familial cancer predisposition syndromes in a series of 82 cases of MB in patients ages <14 years diagnosed at the Giannina Gaslini Children's Hospital, Genoa, between 1987 and 2004. Desmoplastic MB and MB with extensive nodularity (MBEN), were present in 22 of 82 cases (27%) and were more frequent in children ages <or=3 years (13 of 25; 52%). In this age group, MBEN was significantly more frequent than desmoplastic MB and classic MB (P < 0.001) and had a good prognosis. MBEN was associated with GS in 5 of 12 cases. Overall, 8 cases occurred in the context of familial tumor predisposition syndromes (5 GS, 1 each NF1, Li-Fraumeni, and Fragile X) and 7 of these patients were ages <or=3 years at diagnosis. Desmoplastic histology and a more intensive treatment represented independent favorable prognostic factors in multivariate analysis (P = 0.003 and P = 0.0139, respectively). Metastasis was a predictor of bad outcome (P = 0.0001). Our data indicate that biologically different MB entities warrant risk-adapted treatment and that MBEN is strongly associated with GS. Patients, ages <or=3 years, with MB and their families should be investigated for tumor predisposition syndromes such as GS.

Meduloblastoma: correlação entre ressonância magnética convencional, difusão e espectroscopia de prótons

OBJETIVO: Correlacionar os achados de ressonância magnética convencional, difusão e espectroscopia de prótons nos meduloblastomas, e compará-los aos dados da literatura. MATERIAIS E MÉTODOS: Análise retrospectiva de exames de ressonância magnética pré-operatórios de nove pacientes na faixa pediátrica com diagnóstico histológico de meduloblastoma (oito desmoplásicos e um de células gigantes). Foram considerados dados demográficos e características do tumor como localização, característica morfológica, intensidade de sinal, realce, disseminação e achados na difusão e espectroscopia. RESULTADOS: Na maioria dos casos os tumores apresentaram epicentro no vermis cerebelar (77,8%), sendo predominantemente sólido (88,9%), com hipossinal nas seqüências ponderadas em T1 e iso/hipersinal nas seqüências ponderadas em T2 e FLAIR, realce heterogêneo (100%), sinais de disseminação/extensão tumoral (77,8%) e restrição à movimentação das moléculas de água (100%). A espectroscopia de prótons pela técnica STEAM (n = 6) demonstrou redução da relação Naa/Cr (83,3%) e aumento de Co/Cr (100%) e mI/Cr (66,7%), e pela técnica PRESS (n = 7) evidenciou pico de lactato (57,1%). CONCLUSÃO: O conjunto dos achados macroscópicos obtidos pela ressonância magnética, somado às características bioquímicas dos meduloblastomas, têm sido úteis na tentativa de diferenciação entre os principais tumores da fossa posterior.

Pathological and molecular heterogeneity of medulloblastoma

The outcome of medulloblastoma patients and the quality of life of survivors can be improved by both novel therapies and a better tumor classification. This review will focus on the pathology and molecular biology of medulloblastoma and its potential to influence risk assignment and future therapy. A risk stratification system of pediatric medulloblastoma based on a combination of histopathological evaluation and targeted molecular analysis can be outlined. Among the four variants recognized by the 2007 WHO classification, the desmoplastic medulloblastoma and the medulloblastoma with extensive nodularity have significantly better survival with respect to classic medulloblastoma, whereas the large-cell and anaplastic have a worse prognosis. Moreover, 17p loss, MYC amplification/expression, and 1q gain are associated with poor prognosis; in contrast, monosomy 6, mutation of CTNNB1, and trkC expression identify tumors with a favorable outcome. Emerging evidence indicates that the different precursor cell populations that form the cerebellum are susceptible to mutations in signal pathways that regulate their functions; these mutations alter normal development programmes and may result in the formation of distinct variants of medulloblastoma. Better understanding of the growth control mechanisms involved in the development and progression of medulloblastoma will allow improved therapeutic stratification of patients using existing adjuvant therapy as well as the development of new therapeutic approaches.

Defining a role for Sonic hedgehog pathway activation in desmoplastic medulloblastoma by identifying GLI1 target genes

A subgroup of medulloblastomas shows constitutive activation of the Sonic hedgehog pathway with expression of GLI1. We identified the subset of GLI1 transforming target genes specifically expressed in medulloblastomas by comparing GLI1 targets in RK3E cells transformed by GLI1 with the gene expression profile of Sonic hedgehog signature medulloblastomas. We identified 1,823 genes whose expression was altered more than 2-fold in 2 independent RK3E + GLI1 cell lines. We identified 25 whose expression was altered similarly in medulloblastomas expressing GLI1. We identified potential GLI binding elements in the regulatory regions of 10 of these genes, confirmed that GLI1 binds the regulatory regions and activates transcription of select genes, and showed that GLI1 directly represses transcription of Krox-20. We identified upregulation of CXCR4, a chemokine receptor that plays roles in the proliferation and migration of granule cell neuron precursors during development, supporting the concept that reinitiation of developmental programs may contribute to medulloblastoma tumorigenesis. In addition, the targets suggest a pathway through which GLI1 may ultimately affect medulloblastoma cell proliferation, survival and genomic stability by converging on p53, SGK1, MGMT and NTRK2. We identify a p53 mutation in RK3E + GLI1 cells, suggesting that p53 mutations may sometimes shift the balance toward dysregulated tumor cell survival.

Two new patients with Curry–Jones syndrome with trichoblastoma and medulloblastoma suggest an etiologic role of the sonic hedgehog‐patched‐GLI pathway

Curry-Jones syndrome (OMIM #601707) is a rare multiple malformation disorder of unknown etiology, associated with brain and skull abnormalities, polysyndactyly, and defects of the eyes, skin and gastrointestinal tract. We report on two new cases of Curry-Jones syndrome with previously unreported features, including benign and malignant neoplasms. The first patient had typical features of Curry-Jones syndrome as well as multiple intra-abdominal smooth muscle hamartomas and trichoblastoma of the skin. The second patient was born with occipital meningoceles and developed a desmoplastic medulloblastoma. Routine lymphocyte karyotype, GLI3 gene analysis and Patched (PTCH) gene analysis on both patients and chromosome microarray analysis on the first patient were normal. We review the previously reported cases of Curry-Jones syndrome and compare our patients' findings. In view of the association of trichoblastoma with basal cell carcinoma and desmoplastic medulloblastoma with nevoid basal cell carcinoma syndrome (NBCCS) and PTCH mutations, we hypothesize that Curry-Jones syndrome is caused by malfunction of an element in the sonic hedgehog pathway.

MATH-1 production by an adult medulloblastoma suggestive of a cerebellar external granule cell precursor origin

Radiological, histological and molecular findings in an uncommon adult case of cerebellar medulloblastoma suggested an external granular cell precursor origin. This 19-year-old woman had a 1-month history of progressively worsening headache. Neuroimaging studies demonstrated a homogeneously enhanced well-circumscribed mass lesion in the right cerebellar hemisphere and she underwent surgery. Postoperative neuronal imaging studies showed that the tumor located in the cerebellar folia had been removed totally. Pathological examination identified it as a desmoplastic medulloblastoma with subpial and subarachnoid infiltration and some infiltration into the molecular and granular layer via the perivascular space. Polymerase chain reaction and immunohistochemical findings revealed the presence of MATH-1, expressed in cerebellar external granule cell precursors during fetal development, in the tumor cells. These findings suggest that the tumor arose from external granule cell precursors of the cerebellum and that it was therefore of neuronal lineage.

Secretagogin expression in tumours of the human brain and its coverings

Secretagogin is a recently described calcium-binding protein, which is expressed in some neurons of the human brain. In this study we systematically investigated secretagogin expression in 245 tumours of the human brain and its coverings using immunohistochemistry. We found focal or widespread secretagogin expression in tumour cells in 1/18 oligoastrocytomas, 1/19 oligodendrogliomas, 2/20 anaplastic oligodendrogliomas, 2/9 ependymomas, 2/11 anaplastic ependymomas, 2/10 glioblastomas, 3/11 gangliogliomas and 1/2 anaplastic gangliogliomas, 10/10 central neurocytomas, 5/10 classic medulloblastomas, 4/5 desmoplastic medulloblastomas, 3/5 large cell/anaplastic medulloblastomas, 3/5 neuroblastomas, 3/10 meningiomas, 2/10 haemangioblastomas, and 13/19 pituitary adenomas. Further, we observed secretagogin expression in endothelial cells in 5/10 meningiomas, 2/5 haemangiopericytomas, and 2/10 haemangioblastomas. We detected no secretagogin expression in fibrillary astrocytoma, pilocytic astrocytoma, DNT, pineocytoma, pineoblastoma, subependymal giant cell astrocytoma (SEGA), atypical teratoid/rhabdoid tumour (AT/RT), or primary central nervous system lymphoma (PCNSL). We conclude that secretagogin is differentially expressed in human neuronal, glial, and embryonal brain tumours, meningial neoplasms and pituitary adenomas. Our findings indicate that secretagogin is involved in the calcium metabolism of tumour cells and endothelial cells in a subset of neoplasms of the brain and its coverings. Anti-secretagogin immunohistochemistry does not seem to be helpful in most differential diagnostic situations in surgical neuropathology.

Array-based profiling of reference-independent methylation status (aPRIMES) identifies frequent promoter methylation and consecutive downregulation of ZIC2 in pediatric medulloblastoma

Existing microarray-based approaches for screening of DNA methylation are hampered by a number of shortcomings, such as the introduction of bias by DNA copy-number imbalances in the test genome and negligence of tissue-specific methylation patterns. We developed a method designated array-based profiling of reference-independent methylation status (aPRIMES) that allows the detection of direct methylation status rather than relative methylation. Array-PRIMES is based on the differential restriction and competitive hybridization of methylated and unmethylated DNA by methylation-specific and methylation-sensitive restriction enzymes, respectively. We demonstrate the accuracy of aPRIMES in detecting the methylation status of CpG islands for different states of methylation. Application of aPRIMES to the DNA from desmoplastic medulloblastomas of monozygotic twins showed strikingly similar methylation profiles. Additional analysis of 18 sporadic medulloblastomas revealed an overall correlation between highly methylated tumors and poor clinical outcome and identified ZIC2 as a frequently methylated gene in pediatric medulloblastoma.