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Medulloblastoma (MB) comprises a group of heterogeneous paediatric embryonal neoplasms of the hindbrain with strong links to early development of the hindbrain 1–4. Mutations that activate Sonic hedgehog signalling lead to Sonic hedgehog MB in the upper rhombic lip (RL) granule cell lineage 5–8. By contrast, mutations that activate WNT signalling lead to WNT MB in the lower RL 9,10. However, little is known about the more commonly occurring group 4 (G4) MB, which is thought to arise in the unipolar brush cell lineage 3,4. Here we demonstrate that somatic mutations that cause G4 MB converge on the core binding factor alpha (CBFA) complex and mutually exclusive alterations that affect CBFA2T2, CBFA2T3, PRDM6, UTX and OTX2. CBFA2T2 is expressed early in the progenitor cells of the cerebellar RL subventricular zone in Homo sapiens, and G4 MB transcriptionally resembles these progenitors but are stalled in developmental time. Knockdown of OTX2 in model systems relieves this differentiation blockade, which allows MB cells to spontaneously proceed along normal developmental differentiation trajectories. The specific nature of the split human RL, which is destined to generate most of the neurons in the human brain, and its high level of susceptible EOMES +KI67 + unipolar brush cell progenitor cells probably predisposes our species to the development of G4 MB.

© The Author(s), under exclusive licence to Springer Nature Limited 2019, In cancer, recurrent somatic single-nucleotide variants-which are rare in most paediatric cancers-are confined largely to protein-coding genes1-3. Here we report highly recurrent hotspot mutations (r.3A>G) of U1 spliceosomal small nuclear RNAs (snRNAs) in about 50% of Sonic hedgehog (SHH) medulloblastomas. These mutations were not present across other subgroups of medulloblastoma, and we identified these hotspot mutations in U1 snRNA in only

Papillary tumor of the pineal region (PTPR) is a neuroepithelial brain tumor, which might pose diagnostic difficulties and recurs often. Little is known about underlying molecular alterations. We therefore investigated chromosomal copy number alterations, DNA methylation patterns and mRNA expression profiles in a series of 24 PTPRs. Losses of chromosome 10 were identified in all 13 PTPRs examined. Losses of chromosomes 3 and 22q (54%) as well as gains of chromosomes 8p (62%) and 12 (46%) were also common. DNA methylation profiling using Illumina 450k arrays reliably distinguished PTPR from ependymomas and pineal parenchymal tumors of intermediate differentiation. PTPR could be divided into two subgroups based on methylation pattern, PTPR group 2 showing higher global methylation and a tendency toward shorter progression-free survival (P = 0.06). Genes overexpressed in PTPR as compared with ependymal tumors included SPDEF, known to be expressed in the rodent subcommissural organ. Notable SPDEF protein expression was encountered in 15/19 PTPRs as compared with only 2/36 ependymal tumors, 2/19 choroid plexus tumors and 0/23 samples of other central nervous system (CNS) tumor entities. In conclusion, PTPRs show typical chromosomal alterations as well as distinct DNA methylation and expression profiles, which might serve as useful diagnostic tools.

Telomerase reverse transcriptase (TERT) promoter mutations were recently shown to drive telomerase activity in various cancer types, including medulloblastoma. However, the clinical and biological implications of TERT mutations in medulloblastoma have not been described. Hence, we sought to describe these mutations and their impact in a subgroup-specific manner. We analyzed the TERT promoter by direct sequencing and genotyping in 466 medulloblastomas. The mutational distributions were determined according to subgroup affiliation, demographics, and clinical, prognostic, and molecular features. Integrated genomics approaches were used to identify specific somatic copy number alterations in TERT promoter-mutated and wild-type tumors. Overall, TERT promoter mutations were identified in 21 % of medulloblastomas. Strikingly, the highest frequencies of TERT mutations were observed in SHH (83 %; 55/66) and WNT (31 %; 4/13) medulloblastomas derived from adult patients. Group 3 and Group 4 harbored this alteration in

BACKGROUND: Patients with incomplete surgical resection of medulloblastoma are controversially regarded as having a marker of high-risk disease, which leads to patients undergoing aggressive surgical resections, so-called second-look surgeries, and intensified chemoradiotherapy. All previous studies assessing the clinical importance of extent of resection have not accounted for molecular subgroup. We analysed the prognostic value of extent of resection in a subgroup-specific manner. METHODS: We retrospectively identified patients who had a histological diagnosis of medulloblastoma and complete data about extent of resection and survival from centres participating in the Medulloblastoma Advanced Genomics International Consortium. We collected from resections done between April, 1997, and February, 2013, at 35 international institutions. We established medulloblastoma subgroup affiliation by gene expression profiling on frozen or formalin-fixed paraffin-embedded tissues. We classified extent of resection on the basis of postoperative imaging as gross total resection (no residual tumour), near-total resection (30 Gy vs no craniospinal irradiation). The primary analysis outcome was the effect of extent of resection by molecular subgroup and the effects of other clinical variables on overall and progression-free survival. FINDINGS: We included 787 patients with medulloblastoma (86 with WNT tumours, 242 with SHH tumours, 163 with group 3 tumours, and 296 with group 4 tumours) in our multivariable Cox models of progression-free and overall survival. We found that the prognostic benefit of increased extent of resection for patients with medulloblastoma is attenuated after molecular subgroup affiliation is taken into account. We identified a progression-free survival benefit for gross total resection over sub-total resection (hazard ratio [HR] 1·45, 95% CI 1·07-1·96, p=0·16) but no overall survival benefit (HR 1·23, 0·87-1·72, p=0·24). We saw no progression-free survival or overall survival benefit for gross total resection compared with near-total resection (HR 1·05, 0·71-1·53, p=0·8158 for progression-free survival and HR 1·14, 0·75-1·72, p=0·55 for overall survival). No significant survival benefit existed for greater extent of resection for patients with WNT, SHH, or group 3 tumours (HR 1·03, 0·67-1·58, p=0·89 for sub-total resection vs gross total resection). For patients with group 4 tumours, gross total resection conferred a benefit to progression-free survival compared with sub-total resection (HR 1·97, 1·22-3·17, p=0·0056), especially for those with metastatic disease (HR 2·22, 1·00-4·93, p=0·050). However, gross total resection had no effect on overall survival compared with sub-total resection in patients with group 4 tumours (HR 1·67, 0·93-2·99, p=0·084). INTERPRETATION: The prognostic benefit of increased extent of resection for patients with medulloblastoma is attenuated after molecular subgroup affiliation is taken into account. Although maximum safe surgical resection should remain the standard of care, surgical removal of small residual portions of medulloblastoma is not recommended when the likelihood of neurological morbidity is high because there is no definitive benefit to gross total resection compared with near-total resection. FUNDING: Canadian Cancer Society Research Institute, Terry Fox Research Institute, Canadian Institutes of Health Research, National Institutes of Health, Pediatric Brain Tumor Foundation, and the Garron Family Chair in Childhood Cancer Research.

Central neurocytomas (CNs) are rare intraventricular tumors presenting a favorable prognosis after surgery. Their transcriptomic profile is poorly characterized. We performed a microarray transcriptomic study to search for molecular markers that might improve diagnostic accuracy. Microarray analysis was performed on five CNs (3 primary and 2 recurrent CNs) using CodeLink human whole genome bioarrays, and the gene expression in CNs was compared with that in four pineal parenchymal tumors, consisting of two pineocytomas (PCs) and two pineoblastomas (PBs), other periventricular tumors which may present neuronal differentiation. We identified genes that were highly expressed in CNs compared to normal brain and might be candidates for the molecular typing of CNs. Several genes are part of the Wnt/β-catenin and sonic hedgehog signaling pathways or mainly linked to calcium function or maintenance of neural progenitors. Moreover, several genes are overexpressed in both CNs and PCs and/or PBs such as INSM1 and NEUROD4, involved in neural or neuroendocrine differentiation. The overexpression of eight candidate genes in CNs (CHRDL2, IGF2, KiSS-1, CAL2, NTS, NHLH1, RGS16 and SCGN) was confirmed by real-time RT-PCR. Of the genes overexpressed in the recurrent CNs compared to the primary CNs, AQP5, KiSS-1, FZD7, AURKB, UBE2C and PTTG1 are genes which may be involved in tumor progression. Our study shows the potential involvement of various genes in the pathogenesis of CNs. These genes could be potential candidate markers for improving the characterization of CNs and some could be involved in CN tumorigenesis.

Central neurocytoma (CN) is a rare intraventricular tumor presenting a benign histologic appearance and favorable prognosis after surgery. In contrast, "atypical" CN is defined by a high MIB1 proliferation index and/or histologic features of malignancy, which are associated with a poorer outcome. This variant of CN remains somewhat controversial. To better characterize CN and its "atypical" variant, a retrospective multicenter study was conducted on 71 patients presenting with CN. A statistical analysis of clinical, radiologic, and histologic data was conducted to validate prognostic factors. The immunohistochemical phenotype of CNs, analyzed by tissue microarrays, and the MIB1 index were evaluated for 45 cases. Tissue microarrays validated the expression of neuronal markers synaptophysin and NeuN, but not that of glial markers glial fibrillary acidic protein and oligodendrocyte transcription factor 2. In the univariate analysis, a tumor volume ≥30 cm (P=0.025), incomplete surgery (P=0.033), and a mitotic count ≥3 per 10 high-power fields (P=0.009) were predictors of a higher risk of recurrence, unlike the other usual histologic features of malignancy and the high MIB1 index. Partial surgery was the only criterion associated with a poorer outcome in the multivariate model. Our results, based on a large multicenter series, show the striking homogeneity of CNs and do not support the use of histologic criteria as reliable markers to define an "atypical" group of CNs. Our study suggests that the extent of surgery is the main factor to be considered in the prognostic assessment of patients with CN.

M. Fevre-Montange, A. Vasiljevic, D. Frappaz, J. Champier, A. Szathmari, M.-H. Aubriot Lorton, F. Chapon, A. Coulon, I. Quintin Roue, M.-B. Delisle, D. Figarella-Branger, A. Laquerriere, C. Miquel, J.-F. Michiels, M. Peoch, M. Polivka, F. Fauchon and A. Jouvet (2012) Neuropathology and Applied Neurobiology38, 87–94 Utility of Ki67 immunostaining in the grading of pineal parenchymal tumours: a multicentre study Aims: Pineal parenchymal tumours (PPTs) are rare neoplasms that are divided into pineocytoma (PC), pineoblastoma (PB) and PPT of intermediate differentiation (PPTID). Factors affecting the survival of patients with PPTs are morphological subtype and histological grading according to mitotic index and neurofilament immunostaining. Grading criteria to distinguish PPTIDs are difficult to define, particularly when using small specimens. The Ki67 labelling index (LI) might be helpful in distinguishing between grade II and III PPTIDs. Our study was performed to assess the predictive value of the Ki67 LI in a large cooperative series of PPTs and to evaluate whether inclusion of this data would improve and refine the World Health Organization classification. Methods: A retrospective analysis of 33 PPTs was performed. The histological features of the tumours were reviewed and Ki67 LI scoring was evaluated by immunohistochemistry. Data were correlated with the patients' survival. Results: The mean Ki67 LI was significantly different for tumour grades (0 in PC, 5.2 ± 0.4 in PPTID grade II, 11.2 ± 2.0 in PPTID grade III, 36.4 ± 6.2 in PB; P

Pineocytomas (PCs) most frequently occur in adults, but only three cases have been reported in women older than 70 years. In PCs, cytologic pleomorphism, accompanied by ganglion cells intensely expressing neuronal markers, has been described and the presence of pleomorphic cells may lead to an erroneous upgrading of the tumor. We report an unusual case of pleomorphic pineocytoma in an older patient who presented with a slowly growing tumor adjacent to residual pineal gland. The immunohistological markers of the tumoral tissue and the remnant normal pineal tissue were evaluated and compared. In the neoplasm, the large number of cells labeled for neuronal markers, including many pleomorphic cells, confirmed previous findings that a neuronal immunophenotype is common in PC. Reactivity for synaptophysin was stronger in the tumor than the pineal gland, whereas neurofilament protein reactivity was stronger in the pineal gland than the tumor. The neoplastic cells, but not the pineal gland, were reactive for chromogranin A. This dense core vesicle-associated protein immunolabeling is an interesting diagnostic marker for PCs, which makes it possible to distinguish normal pineal parenchyma with low or negative expression from tumoral tissue. This case illustrates that, even though PCs are low-grade tumors, they can increase in size and surgery appears a valuable option.

Pineal region tumors are heterogeneous lesions and include mainly pineal parenchymal tumors (PPTs), papillary tumors of the pineal region (PTPRs) and germ cell tumors (GCTs). This article describes the cystic pineal gland compared with normal tissue and histopathological features of the most frequent pineal region tumors. PPTs are subdivided into pineocytoma (grade I), pineoblastoma (grade IV) and tumors with intermediate differentiation (PPTIDs; grades II–III). A grading system based on the number of mitoses and neurofilament protein expression distinguishes low- from high-grade PPTID. PTPR is a new tumoral entity thought to originate from the subcommissural organ. GCTs include germinoma, embryonal carcinoma, teratoma, yolk sac tumor and choriocarcinoma and are often of mixed histologic composition. New histogenetic data for GCTs are presented.

Water deprivation is a stress that has been associated with activation of several endocrine systems, including circumventricular organs of the central nervous system. The sub-comissural organ (SCO), characterized by its glycoprotein secretion called Reissner's fiber has been suggested to play a role in the regulation of body water balance. Meriones shawi, a semi-desertic rodent characterized by its resistance to long periods of thirst was subjected to water deprivation for 1 and 3 months. Effect of water deprivation was evaluated immunohistochemically on 5-hydroxytryptamine (5-HT; serotonin) system and glycoprotein secretion of the SCO. Our findings demonstrate significant reduction of anti-Reissner's fiber immunoreactive materials within basal and apical parts of the SCO ependymocytes. These changes seem to be the consequence of reduced control by 5-HT fibers reaching the SCO as a concomitant and significant reduction of anti-5-HT immunoreactive fibers are also observed following water deprivation. 5-HT immunoreactive reduction is seen in several regions in the brain including the neurons of origin within the dorsal raphe nucleus and the projecting supra and sub-ependymal fibers reaching the classical ependyma of the third ventricle. The extent of Reissner's fiber and 5-HT immunoreactive changes significantly correlates with the severity of water restriction. We suggest that water deprivation causes changes of the classical ependyma and the specialized ependyma that differentiates into the SCO as well as other cirumventricular organs such as the subfornical organ and the organum vasculosum laminae terminalis known to control drinking behaviors.

This study was undertaken to analyze outcomes and to assess the prognostic impact of age, location, surgery, radiotherapy (RT), and histopathology in a series of adult infratentorial ependymomas.This was a retrospective study of a population of 106 adult patients with infratentorial ependymomas diagnosed between 1990 and 2004. A central pathological review of all cases was performed. Grading was according to the WHO and Marseille's neograding classifications.The series consisted of 58 males (54.7%) and 48 females (45.3%) in the age range of 18-82 years. Using the WHO classification, 88 patients (83.0%) had grade II and 18 patients (17.0%) grade III ependymomas. Using the Marseille's neograding system, 91 patients were low-grade and 15 high-grade. Gross total resection was achieved in 66 patients (62.3%). Thirty-seven patients (35.0%) received adjuvant RT. The 5- and 10-year overall survival rates for the entire cohort were 86.1% and 80.5%, respectively. On multivariate analysis, a preoperative Karnofski performance status score80, no recessus lateral extension and a low histological grade (Marseille's grading) were associated with a longer overall survival. The 5- and 10-year progression-free survival rates for the entire cohort were 70.8% and 57.7%, respectively. On multivariate analysis, no recessus lateral extension, gross total resection and a low histological grade (Marseille's grading) were associated with a longer progression-free survival. Adjuvant RT was significantly associated with a better overall and progression-free survival in incompletely resected WHO grade II ependymomas.This study highlights the key role of histology in the clinical outcome and the fact that gross total resection is a main prognostic factor and the treatment of choice for posterior fossa ependymomas. The use of adjuvant RT in patients with incompletely resected WHO grade II ependymomas appears beneficial, but its effect on high-grade tumors remains to be determined.

Tumors of the pineal region (TPR) include different entities: germ cell tumors (GCT), pineal parenchymal tumors (PPT), meningiomas, and glial tumors. Except for GCT, there are no peripheral markers and histopathological diagnosis needs biopsy or surgery. We studied daily melatonin variations in twenty-nine patients with TPR and five with tectal plate glioma (TPG), used as controls, before and/or after surgery. Before surgery, a melatonin nycthemeral rhythm was observed in patients with TPG and TPR (one cyst, three PPT, one papillary tumor of the pineal region, two meningiomas, six gliomas). Melatonin rhythm was dramatically reduced for undifferentiated or invasive tumors. After surgery, the absence of melatonin variation in some cases could be the consequence of pineal damage by surgery. The contribution of determination of melatonin profiles to the diagnosis of TPR remains limited but of interest. The evidence for melatonin deficiency could justify melatonin administration to prevent the postpinealectomy syndrome.

Cytologic pleomorphism has been described in a limited number of benign pineal tumors, namely pineocytoma (PC) and pineal parenchymal tumors (PPTs) of intermediate differentiation (PPTID). We examined the clinicopathologic features in a retrospective series of 14 cases (seven females and seven males aged from 10 to 65 years) of pleomorphic PPT. Seven cases were PC, with no mitoses and with areas of tumoral cells forming large pineocytomatous rosettes and other areas with giant cells containing hyperchromatic nuclei. The other seven were PPTID, presenting few mitoses (< or =2), a Ki67 proliferation index between 3% and 7%, and predominantly composed of small neoplastic cells and scattered giant cells, sometimes multinucleated. In the 14 tumors, the proportion of pleomorphic areas was variable. Most tumoral cells showed extensive neuronal differentiation with strong expression of neuron-specific enolase, synaptophysin and neurofilaments. Some of the neoplastic cells expressed S100 protein. The follow-up period ranged from 1.2 to 13 years and only one PC and one PPTID progressed after stereotactic biopsy or incomplete resection. The lack of invasiveness and the low proliferation index of these tumors suggest a benign clinical course despite the marked pleomorphism, the latter of which can lead to upgrading.

Pineal parenchymal tumours (PPT) are rare neoplasms and there have been few in vitro studies. Their capacity for synthesizing and secreting melatonin has been only partially examined. We investigated the presence of messenger RNA (mRNA) encoding tryptophan hydroxylase (TPH), arylalkylamine N-acetyltransferase (AANAT), hydroxyindol-O-methyltransferase (HIOMT), three enzymes involved in melatonin synthesis, and c-myc, a tumoural marker, in 10 PPT, one papillary tumour of the pineal region (PTPR), cell cultures derived from four PPTs and from three other tumours of the pineal region, and in normal pineal gland. Moreover, protein expression of TPH was investigated in three PPT and PTPR. Quantitative real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry were used and the melatonin production by tumoural cells in vitro was analysed by radioimmunoassay. We showed that all the tumoural tissues and cells contained c-myc mRNA. mRNAs encoding TPH, AANAT and HIOMT were detected in all PPT, suggesting that tumour cells can synthesize melatonin. Only PPT expressed TPH protein. Cultured cells lost expression of transcripts throughout passages even if ultrastructural study revealed the presence of characteristic organelles in these tumoural cells. Nevertheless, the basal secretion of melatonin observed in one PPT culture is in favour of a maintained melatonin production and secretion by tumoural pinealocytes, but melatonin production was not stimulated by a beta noradrenergic agonist. Moreover, PTPR never expressed mRNA encoding TPH, AANAT and HIOMT. Our results may contribute to a better understanding of the biology of PTT and PTPR and may help to the diagnosis of these rare tumours.

Resume Les tumeurs de la region pineale sont rares, touchant l'enfant et l'adulte, et correspondent a de nombreuses entites differentes. Le diagnostic de localisation avec les techniques modernes d'imagerie est relativement aise. En revanche, le diagnostic de nature est plus difficile et repose sur une expertise anatomopathologique, a l'interieur de chaque entite. Elles comprennent essentiellement trois groupes histologiques : 25 a 30 % sont des tumeurs du parenchyme pineal (TPP) (pinealocytome, pinealoblastome et TPP de differenciation intermediaire selon l'Organisation mondiale de la sante) avec une proposition de nouvelle classification en quatre grades histologiques ; 25 % sont des tumeurs gliales parmi lesquelles des tumeurs papillaires de la region pineale recemment individualisees ; 30 % sont des tumeurs germinales (dysgerminomes et autres tumeurs germinales secretantes ou non). Le traitement de chaque variete est different. Celui des tumeurs germinales pures repose sur la chimiotherapie et l'irradiation du systeme ventriculaire, avec un taux de guerison de plus de 90 %. Dans les tumeurs germinales mixtes, secretantes ou non, le traitement associe la chimiotherapie (carboplatine, VP16 et ifosfamide), une chirurgie eventuelle du reliquat et l'irradiation focalisee. Le traitement des autres entites repose avant tout sur la chirurgie, permettant d'obtenir un fragment significatif de la tumeur et son exerese complete dans de nombreux cas. La chirurgie permet la guerison dans les lesions benignes que sont les kystes, le pinealocytome et les autres processus expansifs benins de la region. Elle doit etre completee par une irradiation dans les formes malignes de TPP avec un pronostic plus reserve, voire une chimiotherapie dans le pinealoblastome. La surveillance a long terme s'impose dans tous les cas, tant pour le suivi neurocognitif que pour detecter une recidive precoce (tumeurs germinales) ou tardive (TPP).

We report the case of a 4-year-old girl with a fourth ventricle tumor diagnosed as a cerebellar liponeurocytoma which recurred, showing ependymal differentiation, 14 months after surgery. Magnetic resonance imaging at initial presentation revealed a large mass in the fourth ventricle, and histology showed a neoplasm characterized by a combination of well-differentiated neurocytes and cells resembling adipocytes. The tumor recurrence was histologically identical to the original tumor in some regions, but with fewer adipose-like cells, while other areas presented an endocrine architecture with oligo-like or pleiomorphic cells, and rosette-like arrangements of tumoral cells were seen around the thin vessels, with features similar to cellular ependymoma. The cells in the liponeurocytoma areas expressed synaptophysin, chromogranin A, and epithelial membrane antigen. Glial fibrillary acidic protein was expressed in some dispersed tumoral cells, in lipidized tumoral cells, and in reactive astrocytes. Cytokeratin was focally expressed in the ependymal region of the recurrence. The immunophenotype of our case, with glial, ependymal, and neuronal or neuroendocrine markers, suggest a neurocytoma with lipomatous and ependymal differentiation. This tumor resembled those derived from circumventricular organs. Its localization in the area postrema region led us to hypothesize that it may be derived from this circumventricular organ.

The histological diagnosis of low-grade astrocytomas and oligodendrogliomas (WHO grade II) is often challenging, particularly in cases that show both astrocytic and oligodendroglial differentiation. We carried out gene expression profiling on 17 oligodendrogliomas (93% with LOH 1p and/or 19q) and 15 low-grade astrocytomas (71% with a TP53 mutation), using a cDNA array containing 1176 cancer-related genes. In oligodendrogliomas, 40 genes showed on average higher expression (at least a two-fold increase) than in astrocytomas, including DES, TDGF1, TGF-beta, GABA-BR1A, Histone H4, CDKN1A, PCDH43, Rho7 and Jun-D, while 39 genes were expressed at lower levels (at least a two-fold decrease), including JNK2, ITGB4, JNK3A2, RhoC, IFI-56K, AAD14 and EGFR. Immunohistochemistry revealed nuclear staining of Jun-D in oligodendrogliomas, in contrast to the immunoreactivity of cytoplasm and cell processes in low-grade astrocytomas. Partial least-squares analysis of the 79 genes at least two-fold differentially expressed between oligodendrogliomas and low-grade astrocytomas demonstrated perfect separation of oligodendrogliomas from low-grade astrocytomas and normal cerebral white matter. Clustering analysis based on the entire gene set divided the 17 subjects with oligodendrogliomas into two subgroups with significantly different survival (log-rank test, P=0.0305; survival to 5-years, 80 vs 0%, P=0.048). These results demonstrate that oligodendrogliomas and low-grade astrocytomas differ in their gene expression profiles, and that there are subgroups of oligodendroglioma with distinct expression profiles related to clinical outcome.

Mitotic activity in the forebrain subventricular zone is well documented but only in vitro reports suggest the presence of multi-potent stem cells all along the adult mammalian neuraxis. We demonstrate, following cerebroventricular infusion of labeled nucleotides in rat brain, a mitotic activity in the choroid plexus, the ependymal and subependymal layers of the mid- and hindbrain. This proliferation, which probably enables renewal of these structures, was unaffected by the destruction of their serotonergic innervations. Nestin, a marker of immature neural cells, was observed in some proliferative subependymal cells, some classical ependymocytes and in the specialized ependymocytes of the subcommissural organ, the collicular recess and the tanycytes. These observations indicate the presence of immature proliferative cells in the third and fourth periventricular structures, which may generate neural cells.

Somatostatin is a potent antiproliferative signal in both tumoral and normal mammalian cells, and altered somatostatin receptor (sst) expression is associated with carcinogenesis in human tissues. In this study, two normal and three tumoral human pineal glands were analyzed using the reverse transcriptase–polymerase chain reaction (RT-PCR) for the presence of mRNA coding for the five different somatostatin receptors (sst1–sst5). Pineal parenchymal tumor (PTT) differentiation was confirmed by immunohistochemical detection of neuroendocrine markers (synaptophysin, neurofilaments, and chromogranin A). The presence of mRNA coding for c-myc, a proto-oncogene, and for tryptophan hydroxylase (TPOH), serotonin N-acetyltransferase (NAT), and hydroxyindole-O-methyltransferase (HIOMT), enzymes of the melatonin pathway, was also analyzed by RT-PCR. Only the tumoral tissues contained c-myc mRNA. All five tissues contained TPOH, NAT, and HIOMT mRNA, the levels of HIOMT mRNA being lower in PPT than in the normal pineal gland, suggesting that PPT retain the ability to synthesize melatonin. All tissues contained sst1, sst2, and sst3 transcripts, but not sst4, while small amounts of sst5 mRNA were only found in normal pineal glands. Real-time PCR, performed only with the most abundant subtype sst2, evidenced an about sixfold higher level in normal pineal glands. These results demonstrate the presence of somatostatin receptors in the human pineal gland, as described in other species, and point to a differential expression of the sst2 and sst5 subtypes associated with carcinogenesis.

1. Tryptophan hydroxylase (TPOH) is the first enzyme in the melatonin synthesis pathway and the rate-limiting enzyme in serotonin synthesis. We established in this study an in vitro model of ovine pinealocytes to investigate the role of TPOH in melatonin production. 2. We demonstrated that TPOH is highly expressed both in vivo and in vitro at the protein and mRNA levels. In vitro pinealocytes show ultrastructural features similar to those previously described in vivo. 3. Moreover, our in vitro model allowed us to study the regulation mechanisms for melatonin synthesis in sheep pinealocytes and to demonstrate that both transcriptional and posttranscriptional mechanisms are involved. 4.In particular, our results suggest that TPOH plays an essential role in the regulation of melatonin synthesis.

Purpose Medulloblastoma comprises four distinct molecular subgroups: WNT, SHH, Group 3, and Group 4. Current medulloblastoma protocols stratify patients based on clinical features: patient age, metastatic stage, extent of resection, and histologic variant. Stark prognostic and genetic differences among the four subgroups suggest that subgroup-specific molecular biomarkers could improve patient prognostication. Patients and Methods Molecular biomarkers were identified from a discovery set of 673 medulloblastomas from 43 cities around the world. Combined risk stratification models were designed based on clinical and cytogenetic biomarkers identified by multivariable Cox proportional hazards analyses. Identified biomarkers were tested using fluorescent in situ hybridization (FISH) on a nonoverlapping medulloblastoma tissue microarray (n = 453), with subsequent validation of the risk stratification models. Results Subgroup information improves the predictive accuracy of a multivariable survival model compared with clinical biomarkers alone. Most previously published cytogenetic biomarkers are only prognostic within a single medulloblastoma subgroup. Profiling six FISH biomarkers (GLI2, MYC, chromosome 11 [chr11], chr14, 17p, and 17q) on formalin-fixed paraffin-embedded tissues, we can reliably and reproducibly identify very low-risk and very high-risk patients within SHH, Group 3, and Group 4 medulloblastomas. Conclusion Combining subgroup and cytogenetic biomarkers with established clinical biomarkers substantially improves patient prognostication, even in the context of heterogeneous clinical therapies. The prognostic significance of most molecular biomarkers is restricted to a specific subgroup. We have identified a small panel of cytogenetic biomarkers that reliably identifies very high-risk and very low-risk groups of patients, making it an excellent tool for selecting patients for therapy intensification and therapy de-escalation in future clinical trials.

We investigated immunohistochemically the subcommissural organ (SCO) glycoprotein secretion, its serotoninergic (5-HT) innervation and the possible control of this innervation upon the SCO activity in lizards (Agama impalearis, Saurodactylus mauritanicus and Eumeces algeriensis). Inside the SCO, interspecific differences in the intensity and the distribution of both secretory product and 5-HT nerve fibers were observed. Compared with Agama and Eumeces, the SCO of Saurodactylus displayed intense secretory products and several 5-HT fibers. In Saurodactylus, i.p. injection of parachlorophenylalanine, a potent inhibitor of 5-HT synthesis, produced a marked decrease of SCO secretory product. We report in this study species differences of the lizard SCO secretory activity and its possible physiological control by 5-HT innervation, as previously demonstrated in mammals.

The levels of mRNAs coding for tryptophan hydroxylase (TPOH), the first enzyme in melatonin synthesis, have been investigated by quantitative reverse transcription of RNA, followed by polymerase chain reaction (RT-PCR), after stimulation of neonatal pineal organ cultures with Noradrenaline (NA). TPOH mRNAs were specifically amplified from various adult tissues, namely the pineal gland, raphe, retina, and kidney, but not the lung. PCR signals for TPOH were detected in the neonatal pineal gland in the absence of stimulation. Stimulation of neonatal pineal organ culture with 0.1 μM NA resulted in a significant increase (×2.5) in expression of TPOH mRNAs, whereas higher doses (1 and 10 μM) had no effect. All concentrations of NA enhanced melatonin secretion. Our results suggest that the level of TPOH mRNAs can be controlled by NA and that this effect might be implicated in the gene level regulation of the daily enzyme rhythm in the rat pineal gland. J. Neurosci. Res. 49:750–758, 1997. © 1997 Wiley-Liss, Inc.

Purpose Reports detailing the prognostic impact of TP53 mutations in medulloblastoma offer conflicting conclusions. We resolve this issue through the inclusion of molecular subgroup profiles. Patients and Methods We determined subgroup affiliation, TP53 mutation status, and clinical outcome in a discovery cohort of 397 medulloblastomas. We subsequently validated our results on an independent cohort of 156 medulloblastomas. Results TP53 mutations are enriched in wingless (WNT; 16%) and sonic hedgehog (SHH; 21%) medulloblastomas and are virtually absent in subgroups 3 and 4 tumors (P < .001). Patients with SHH/TP53 mutant tumors are almost exclusively between ages 5 and 18 years, dramatically different from the general SHH distribution (P < .001). Children with SHH/TP53 mutant tumors harbor 56% germline TP53 mutations, which are not observed in children with WNT/TP53 mutant tumors. Five-year overall survival (OS; ± SE) was 41% ± 9% and 81% ± 5% for patients with SHH medulloblastomas with and without TP53 mutations, respectively (P < .001). Furthermore, TP53 mutations accounted for 72% of deaths in children older than 5 years with SHH medulloblastomas. In contrast, 5-year OS rates were 90% ± 9% and 97% ± 3% for patients with WNT tumors with and without TP53 mutations (P = .21). Multivariate analysis revealed that TP53 status was the most important risk factor for SHH medulloblastoma. Survival rates in the validation cohort mimicked the discovery results, revealing that poor survival of TP53 mutations is restricted to patients with SHH medulloblastomas (P = .012) and not WNT tumors. Conclusion Subgroup-specific analysis reconciles prior conflicting publications and confirms that TP53 mutations are enriched among SHH medulloblastomas, in which they portend poor outcome and account for a large proportion of treatment failures in these patients.

Germ cell tumors (GCTs) classically occur in gonads. However, they are the most frequent neoplasms in the pineal region. The pineal location of GCTs may be caused by the neoplastic transformation of a primordial germ cell that has mismigrated. The World Health Organization (WHO) recognizes 5 histological types of intracranial GCTs: germinoma and non-germinomatous tumors including embryonal carcinoma, yolk sac tumor, choriocarcinoma and mature or immature teratoma. Germinomas and teratomas are frequently encountered as pure tumors whereas the other types are mostly part of mixed GCTs. In this situation, the neuropathologist has to be able to identify each component of a GCT. When diagnosis is difficult, use of recent immunohistochemical markers such as OCT(octamer-binding transcription factor)3/4, Glypican 3, SALL(sal-like protein)4 may be required. OCT3/4 is helpful in the diagnosis of germinomas, Glypican 3 in the diagnosis of yolk sac tumors and SALL4 in the diagnosis of the germ cell nature of an intracranial tumor. When the germ cell nature of a pineal tumor is doubtful, the finding of an isochromosome 12p suggests the diagnosis of GCT. The final pathological report should always be confronted with the clinical data, especially the serum or cerebrospinal fluid levels of β-human chorionic gonadotropin (HCG) and alpha-fetoprotein.

Central neurocytomas (CNs) are rare intraventricular tumors presenting a favorable prognosis after surgery. Their transcriptomic profile is poorly characterized. We performed a microarray transcriptomic study to search for molecular markers that might improve diagnostic accuracy. Microarray analysis was performed on five CNs (3 primary and 2 recurrent CNs) using CodeLink human whole genome bioarrays, and the gene expression in CNs was compared with that in four pineal parenchymal tumors, consisting of two pineocytomas (PCs) and two pineoblastomas (PBs), other periventricular tumors which may present neuronal differentiation. We identified genes that were highly expressed in CNs compared to normal brain and might be candidates for the molecular typing of CNs. Several genes are part of the Wnt/β-catenin and sonic hedgehog signaling pathways or mainly linked to calcium function or maintenance of neural progenitors. Moreover, several genes are overexpressed in both CNs and PCs and/or PBs such as INSM1 and NEUROD4, involved in neural or neuroendocrine differentiation. The overexpression of eight candidate genes in CNs (CHRDL2, IGF2, KiSS-1, CAL2, NTS, NHLH1, RGS16 and SCGN) was confirmed by real-time RT-PCR. Of the genes overexpressed in the recurrent CNs compared to the primary CNs, AQP5, KiSS-1, FZD7, AURKB, UBE2C and PTTG1 are genes which may be involved in tumor progression. Our study shows the potential involvement of various genes in the pathogenesis of CNs. These genes could be potential candidate markers for improving the characterization of CNs and some could be involved in CN tumorigenesis.

Medulloblastoma, the most common malignant paediatric brain tumour, is currently treated with nonspecific cytotoxic therapies including surgery, whole-brain radiation, and aggressive chemotherapy. As medulloblastoma exhibits marked intertumoural heterogeneity, with at least four distinct molecular variants, previous attempts to identify targets for therapy have been underpowered because of small samples sizes. Here we report somatic copy number aberrations (SCNAs) in 1,087 unique medulloblastomas. SCNAs are common in medulloblastoma, and are predominantly subgroup-enriched. The most common region of focal copy number gain is a tandem duplication of SNCAIP, a gene associated with Parkinson's disease, which is exquisitely restricted to Group 4 alpha. Recurrent translocations of PVT1, including PVT1-MYC and PVT1-NDRG1, that arise through chromothripsis are restricted to Group 3. Numerous targetable SCNAs, including recurrent events targeting TGF-beta signalling in Group 3, and NF-kappa B signalling in Group 4, suggest future avenues for rational, targeted therapy.

Neuroepithelial papillary tumor of the pineal region (PTPR) has been defined as a distinct entity that is increasingly being recognized, with 96 cases now reported. This tumor shares morphologic features with both ependymomas and choroid plexus tumors. PTPR is characterized by an epithelial-like growth pattern in which the vessels are covered by layers of tumor cells forming perivascular pseudorosettes. These tumors exhibit various combinations of papillary and solid architecture, making the differential diagnosis of PTPR difficult to establish. We report the detailed description of the histopathologic features of a large series of PTPRs from 20 different centers and distinguish 2 subgroups of tumors with either a striking papillary growth pattern or a papillary and solid growth pattern. We highlight the findings that PTPRs have unusual vessels with multiple lumina and frequently show detachment of the border of the tumoral cells from the vascular wall. The 2 PTPR subgroups present similar clinical characteristics and immunophenotypes. We confirmed and extended the results of previous ultrastructural studies on the presence of intercellular junctions at the apical part of tumoral cells. The expression of the tight junction proteins claudin-1, claudin-2, and claudin-3 was investigated by immunohistochemistry. Claudin-1 and claudin-3, but not claudin-2, were expressed in PTPRs and in the fetal subcommissural organ, potentially the origin of this tumor. In contrast, all 3 claudins were expressed in choroid plexus papillomas. Claudin expression may help in the diagnosis of PTPRs and can be used in combination with other markers, such as CK18, NCAM, E-cadherin, MAP-2, and Kir 7.1.

The aim of this study was to examine by quantitative in situ hybridization the effects of an acute stress on the expression of the POMC gene in the mediobasal hypothalamus (MBH) of the rat. In control animals, the highest levels of POMC mRNA were observed in the posterior periventricular region of the MBH. Lower levels were found in the anterior and posterior arcuate nucleus. At the end of a one hour immobilization, a small decrease (−8%) was observed in the periventricular region only. Four hours after the end of immobilization, increases in POMC mRNA levels were detected in the anterior part (7%), in the posterior part (25%) and in the periventricular region (13%) of the MBH. These results suggest that MBH POMC-derived peptides might be an important component in the central response to stress.

Folate is essential for purine and thymidylate biosynthesis and in methyl transfer for DNA methylation. Folate deficiency alters the secretion of melatonin, a hormone involved in circadian rhythm entrainment, and causes hyperhomocysteinemia because of disruption of homocysteine metabolism. Adverse effects of homocysteine include the generation of free radicals, activation of proliferation or apoptosis, and alteration of gene expression. The liver is an important organ for folate metabolism, and its genome analysis has revealed numerous clock-regulated genes. The variations at the level of their expression during folate deficiency are not known. The aim of our study was to investigate the effects of folate deficiency on gene expression in the mouse liver. A control group receiving a synthetic diet and a folate-depleted group were housed for 4 weeks on a 12-hour/12-hour light/dark cycle. Three mice from each group were euthanized under dim red light at the beginning of the light cycle, and 3, at the beginning of the dark period. Gene expression was studied in a microarray analysis. Of the 53 genes showing modified daily expression in the controls, 52 showed a less marked or no difference after folate depletion. Only 1, lpin1, showed a more marked difference. Ten genes coding for proteins involved in lipid metabolism did not show a morning/evening difference in controls but did after folate depletion. This study shows that, in the mouse liver, dietary folate depletion leads to major changes in expression of several genes involved in fatty acid metabolism, DNA synthesis, and expression of circadian genes.

Ependymomas are neuroepithelial tumors that arise from the ependymal layer bordering the cerebral ventricles and spinal canal. Intracranial ependymoma represents a major encephalic tumor in children, while spinal ependymoma develops more frequently in adults. To understand the pharmacoresistance that characterizes this tumoral entity, we analyzed the level of expression and localization of three major efflux transport proteins with a multidrug resistance function, P‐glycoprotein, multidrug resistance‐related protein 1 (MRP1) and breast cancer resistance protein (BCRP), in a series of 25 ependymomas from both children and adults. Real‐time‐PCR analysis showed that all three genes were expressed in all tumors, with no apparent correlation between the level of expression and either age or tumor grade. The MRP1 transcript was expressed at a significantly higher level in spinal tumors than in intracranial tumors. The expression of the proteins corresponding to these genes was confirmed by Western blot analysis. In an immunohistochemical study, P‐glycoprotein and BCRP were shown to be associated with the tumoral vessels, where they presented a luminal localization, a prerequisite for their efflux drug activity into the blood. These data indicate that a biochemical, transporter‐dependent blood–tumor barrier may exist in ependymomas, which may reduce the tumoral bioavailability of lipophilic and amphiphilic anticancer drugs.

Pineal parenchymal tumors (PPTs) are rare, accounting for 0.3% of all neoplasms of the central nervous system. PPTs constitute a morphologic continuum from the benign pineocytomas (PCs, WHO grade I) through pineal parenchymal tumors of intermediate differentiation (PPTIDs, WHO grades II or III) to the highly aggressive pineoblastomas (PBs, WHO grade IV). PCs are well-differentiated, slow-growing adult tumors that are characterized by large pineocytomatous rosettes and strong expression of neuronal markers such as synaptophysin and neurofilament protein. Their prognosis is favorable after complete surgical resection. PPTIDs are intermediate tumors that may behave as low-grade or high-grade neoplasms. There is no consensus regarding the criteria used to predict the biologic behavior of PPTIDs. Some authors have suggested mitotic count, Ki-67 immunolabeling index, and neurofilament protein immunoexpression as potential tools in this setting. The prognosis of PPTIDs is variable. PBs are poorly differentiated, “small blue cell” pediatric tumors with a high proliferative activity and a tendency to disseminate through the cerebrospinal fluid. The outcome is usually poor. Treatment of PB is multimodal including surgery, radiotherapy, and chemotherapy. In daily practice, molecular biology does not play a major role in the diagnosis of PPTs. The main prognostic factors in PPTs are age, histopathologic subtype, extent of surgical resection, and staging at diagnosis.

Tyrosine hydroxylase (TH) tissue concentration was determined by immunostaining of tissue sections directly transferred onto nitrocellulose membranes in the restricted region of the noradrenergic perikarya of the locus coeruleus (LC) along its postero-anterior axis. TH containing cells were systematically counted on adjacent fixed sections stained by immunohistochemistry. The absolute quantity of TH was estimated in each section and was found to be linearly related to the number of TH immuno-positive cells found in the adjacent section. The ratio between these two parameters was thus used as an index of the cellular concentration of TH in noradrenergic cells. In the LC of control rats, the TH cellular concentration was lower (−39%) in the anterior than in the posterior half of the structure. Three days after an injection of 20 mg/kg of RU24722, an eburnamine derivative known to increase the quantity of TH in the LC, increases in quantities of TH were found in both portions of the LC. Moreover in the posterior LC the increase in the amount of TH resulted from a significant increase in the number of TH-immunopositive cells. In the anterior part, however, it was primarily the result of a significant increase in TH cellular concentration. Throughout the LC there was an increase in the cellular concentration of TH which was inversely proportional to the concentrations found in control animals. TH mRNA content was measured by a quantitative in situ hybridization in sections of both the posterior and anterior LC one day after a single injection of RU24722 at the same dose. The quantity of TH mRNA was significantly increased in both parts. The number of TH mRNA-expressing neurons also increased, especially in the anterior LC. Thus the effects at the level of TH protein and TH mRNA were strikingly parallel though increase in TH protein occurred later than the increase in the TH mRNA. These results suggest that in the rat LC: (1) there is a significant population of ‘sleeping cells’ in which TH expression is either inactivated or, at a low level of activation; (2) TH cellular concentration could exert a retrocontrol on its own expression in cells of the LC that contained TH and (3) TH expression appears to be regulated by different selective mechanisms in these two different subpopulations of noradrenergic cells within the LC.

The low cerebral bioavailability of various drugs is a limiting factor in the treatment of neurological diseases. The restricted penetration of active compounds into the brain is the result of the same mechanisms that are central to the maintenance of brain extracellular fluid homeostasis, in particular from the strict control imposed on exchanges across the blood-brain interfaces. Direct drug entry into the brain parenchyma occurs across the cerebral microvessel endothelium that forms the blood-brain barrier. In addition, local drug concentration measurements and cerebral imaging have clearly shown that the choroid plexuses - the main site of the blood-cerebrospinal fluid (CSF) barrier - together with the CSF circulatory system also play a significant role in setting the cerebral bioavailability of drugs and contrast agents. The entry of water-soluble therapeutic compounds into the brain is impeded by the presence of tight junctions that seal the cerebral endothelium and the choroidal epithelium. The cerebral penetration of many of the more lipid-soluble molecules is also restricted by various classes of efflux transporters that are differently distributed among both blood-brain interfaces, and comprise either multidrug resistance proteins of the ATP-binding cassette superfamily or transporters belonging to several solute carrier families. Expression of these transporters is regulated in various pathophysiological situations, such as epilepsy and inflammation, with pharmacological consequences that have yet to be clearly elucidated. As for brain tumour treatments, their efficacy may be affected not only by the intrinsic resistance of tumour cells, but also by endothelial efflux transporters which exert an even greater impact than the integrity of the endothelial tight junctions. Relevant to paediatric neurological treatments, both blood-brain interfaces are known to develop a tight phenotype very early on in postnatal development, but the developmental profile of efflux transporters still needs to be assessed in greater detail. Finally, the exact role of the ependyma and pia-glia limitans in controlling drug exchanges between brain parenchyma and CSF deserves further attention to allow more precise predictions of cerebral drug disposition and therapeutic efficacy.

Meningiomas, one of the largest subgroup of intracranial tumours are generally benign, but can progress to malignancy. They are classified into the three World Health Organization grades: benign, atypical and anaplastic meningiomas. Various histopathological features have been associated with aggressiveness or recurrence. Several genes have been suggested as prognostic factors, but molecular signatures have not permitted the classification of the tumours into the three grades. We have performed a microarray transcriptomic study on 17 meningiomas of different malignancy using CodeLink Uniset Human Whole Genome Bioarrays to try to distinguish the different grades and histopathological subtypes. Unsupervised hierarchical clustering classified the meningiomas into groups A, B and C, which corresponded to the three grades except for 3 benign meningiomas with higher proliferation indexes and/or recurrence, included in the atypical group. Several genes involved in cell adhesion (CD44, LOX), cell division (CKS2, BIRC5 and UBE2C), cell differentiation (Notch1) or signal transduction (ARHGAP28) were upregulated, whereas tumour suppressor genes (LR1B, DRR1, PLZF, GPX3, SYNPO, TIMP3 and HOPS) and genes involved in cell adhesion (PROS1), proliferation (SERPINF1 and PDGFD) and differentiation (AOX1) were downregulated in groups B and C compared to group A. In the benign tumours, we identified genes with signatures specific for fibroblastic meningiomas (FBLN1, Tenascin C and MMP2 encoding extracellular matrix proteins) and for meningothelial meningiomas (MLPH, DEFB1 and FAT3), suggesting different mechanisms involved in the tumorigenesis of these subtypes. This microarray-based expression profiling study revealed candidate genes and pathways that may contribute to a better understanding of the recurrence of a benign meningioma. Our results might make it possible to determine which benign meningiomas might recur despite complete resection, and will provide helpful information for neurosurgeons in the follow-up of the patients.

Proopiomelanocortin (POMC) is a 36 kDa glycoprotein implicated in homeostatic balance. We used in situ hybridization histochemistry coupled with quantitative autoradiography to determine the anatomical distribution of POMC mRNA-expressing neurons in the arcuate nucleus (AN) and to examine the effects of prolonged dehydration on POMC gene expression in a semi-desert rodent, Meriones shawi (Shaw’s Jird). In the hypothalamus of control animals, POMC mRNA-expressing neurons were exclusively localized in the AN and they showed a differential distribution and density along its rostro-caudal subdivisions. In dehydrated animals, water deprivation caused a decrease in POMC mRNA labeling in the AN. These results suggest that dehydration stress can induce negative regulation of POMC gene expression in this species. A comparative study of weight variation between control and dehydrated animals showed a weight loss followed by stabilization of weight during prolonged dehydration.

Meningiomas represent one of the largest subgroups of intracranial tumors. They are generally benign, but may show a histological progression to malignancy. Grades II and III meningiomas have been less well studied and are not well controlled because of their aggressive behaviour and recurrences. There is no consensus on therapeutic strategies and no prognostic factors are known. In order to determine these parameters, a multi-institutional retrospective analysis was performed in France with the support of the Neuro-Oncology Club of the French Neurosurgical Society. This study was performed on 199 adults treated for WHO grade II (166 patients) or grade III (33 patients) meningiomas between 1990 and 2004 in the Neurosurgery Departments of five French University Hospitals. Data on epidemiology, clinical behaviour and therapy were collected. Overall survival and progression-free survival were analysed as a function of each possible prognostic factor. For patients with grade II meningiomas, the 5- and 10-year OS rates were 78.4 and 53.3%, respectively, while, for patients with grade III meningiomas, the corresponding values were 44.0 and 14.2%. For patients with grade II meningiomas, the 5- and 10-year PFS rates were 48.4 and 22.6%, respectively, the corresponding values for patients with grade III meningiomas being 8.4 and 0%. For the grade II meningiomas, univariate analysis showed that age < 60 years (P < 0.0001) and Simpson 1 resection (P = 0.055) were associated with a longer OS. For the grade III meningiomas, univariate analysis showed that age < 60 years (P < 0.0001) and RT (P = 0.036) were associated with a longer OS. Histological grade II was found to be associated with a longer PFS (P = 0.0032) and RT reduced the PFS in grade II meningiomas (P = 0.0006) There were no other prognostic factors in terms of PFS for grades II and III meningiomas in univariate analysis. Multivariate analysis confirmed that age (< 60 years), Simpson 1 and histological grade II were independent prognostic factors for survival. This retrospective study might improve the management of grades II and III meningiomas. Prospective trials should delineate strong therapeutic guidelines for high-grade meningiomas.

This study was performed to determine whether neurons, where γ-aminobutyric acid (GABA) and serotonin (5-HT) coexist, represent neuronal entities which can survive in vitro. In dissociated cultures from 18-day-old embryonic rat metencephalon, it was possible to develop glial and neuronal cells. Among the neurons, some of them, which contain glutamate decarboxylase or are capable of accumulating [ 3 H]GABA are GABAergic; others, containing tryptophan hydroxylase or 5-HT are serotoninergic. By combining radioautography and immunocytochemistry, it was possible to observe neurons where 5-HT and GABA coexist. Cultures might be a suitable model to study the functioning (release or synthesis of both neurotransmitters) of neurons where two classical neurotransmitters coexist.

Cerebral homeostasis results from the presence of the protective blood-brain and blood-cerebrospinal fluid barriers located respectively at the brain capillary endothelium and the choroid plexus epithelium. ABCb1 (Pgp) and ABCc1 (Mrp1) transporters are two major proteins of neuroprotection whose localization and functional significance at both barriers remain partly unsettled. We conducted a comparative analysis of their relative protein content between the two blood-brain interfaces. Microvessels and choroid plexuses located in the fourth and lateral ventricles were isolated from developing and adult rat brains, and whole homogenates were submitted to quantitative Western blot analysis by using standard curves generated from one of the samples. In adult, choroid plexus-associated Pgp content was less than 0.5% of the level in microvessels, whereas Mrp1 content in microvessels was 4% of that in the fourth ventricle choroid plexus. Pgp but not Mrp1 was enriched in microvessels over parenchyma. In choroid plexuses, Mrp1 displayed a basolateral epithelial localization, and reached its high adult protein level, early during postnatal development. In postnatal as in adult microvessels, Pgp localization appeared luminal. However, by contrast to Mrp1, the level of this transporter increased 4.6-fold between 9-day-old and adult animals. Western blot analysis of human samples confirmed the mirror image of Pgp and Mrp1 expression between the two barriers. We conclude that there are major differences in the mechanisms by which blood-brain interfaces fulfill their neuroprotective functions. The data also highlight the significance of the neuroprotective function of the choroid plexus during brain maturation, when the microvasculature is still developing.

In situ hybridization (ISH) was used to study at the electron microscope level, the subcellular localization of oxytocin (OT) mRNA in the rat hypothalamic magnocellular neurons. Rat brains were fixed with paraformaldehyde and glutaraldehyde and vibratome slices were incubated with a 25-base synthetic oligonucleotide complementary to OT mRNA and labelled at the 3′-end with [ 3 H]dCTP. Hybridized slices were embedded in Epon after post-fixation with osmium tetroxide and cut into ultrathin sections that were processed for ultrastructural radioautography. OT mRNA was observed in magnocellular neurons of supra-optic and paraventricular nuclei in the vibratome sections. On ultrathin sections, the cytological preservation appeared to be satisfactory. Except for a few silver grains over the nucleus, sometimes close to its membrane, most grains were localized over the cytoplasm of some magnocellular neurons, where they frequently overlapped the endoplasmic reticulum. To decrease exposure time, ISH was also performed with OT probes labelled with a long tritiated tail. In this case, clusters of silver grains occurred over the cell nuclei not only in magnocellular neurons but also in non-secretory neurons and even in glial cells. However, an excess of poly C added to the hybridization buffer strongly decreased this non-cytoplasmic labelling. In conclusion, the results obtained with the short-tailed oligonucleotides demonstrate that these synthetic oligonucleotides have possible applications for the ultrastructural localization of mRNAs and constitute a powerful tool for the dynamic study of cellular mRNA processing in several physiological and experimental conditions.

Although most pituitary tumors are benign, some are invasive or aggressive. In the absence of specific markers of malignancy, only tumors with metastases are considered malignant. To identify markers of invasion and aggressiveness, we focused on prolactin (PRL) tumors in the human and rat. Using radiology and histological methods, we classified 25 human PRL tumors into three groups (non-invasive, invasive, and aggressive–invasive) and compared them with a model of transplantable rat PRL tumors with benign and malignant lineages. Combining histological(mitoses and labeling for Ki-67, P53, pituitary transforming tumor gene (PTTG), and polysialic acid neural cell adhesion molecule) and transcriptomic (microarrays and q-RTPCR) methods with clinical data (post-surgical outcome with case–control statistical analysis), we found nine genes implicated in invasion (ADAMTS6, CRMP1, and DCAMKL3) proliferation (PTTG, ASK, CCNB1, AURKB, and CENPE), or pituitary differentiation (PITX1) showing differential expression in the three groups of tumors (P = 0.015 to 0.0001). A case–control analysis, comparing patients in remission (9 controls) and patients with persistent or recurrent tumors (14 cases) revealed that eight out of the nine genes were differentially up- or downregulated (P = 0.05 to 0.002), with only PTTG showing no correlation with clinical course (P = 0.258). These combined histological and transcriptomic analyses improve the pathological diagnosis of PRL tumors, indicating a reliable procedure for predicting tumor aggressiveness and recurrence potential. The similar gene profiles found between non-invasive human and benign rat tumors, as well as between aggressive–invasive human and malignant rat tumors provide new insights into malignancy in human pituitary tumors.

Tumors of the pineal region are rare and relatively few centers around the world have published substantial numbers of carefully studied cases. This review gives a historical account of our understanding of the normal pineal and the evolution of the classification of tumors and other mass lesions of the pineal region in human beings. Based on our experience over the past 30 years, a working classification is proposed and recent advances in the neuropathology of these lesions are discussed.

Papillary tumor of the pineal region (PTPR) is a recently described tumor entity thought to arise from the specialized ependyma of the subcommissural organ. Whereas histologic features of PTPR are well defined, data on the prognostic value of PTPR remain scarce. We therefore investigated clinicopathologic features, including data on progression-free survival and overall survival, in a retrospective series of 31 PTPR. The age of the 14 males and 17 females ranged from 5 to 66 years (median age, 29 years). Histologically, all tumors were characterized by an epithelial-like growth pattern in which the vessels were covered by layers of columnar or cuboidal tumor cells forming perivascular pseudorosettes. Most of the tumor cells showed strong expression of neuron-specific enolase, cytokeratins (particularly CK18), S-100 protein, and vimentin. Most PTPRs examined also expressed microtubule-associated protein-2. Expression of synaptophysin, epithelial membrane antigen, transthyretin, neural cell adhesion molecule, and nestin was encountered in some tumors. Gross total resection could be achieved in 21 of 31 cases; 15 patients received radiotherapy on resection of the primary tumor. Nevertheless, the majority of patients experienced recurrences; 5-year estimates for overall survival and progression-free survival were 73% and 27%, respectively. To conclude, the clinical course of PTPR is characterized by frequent local recurrence, and the value of radiotherapy on disease progression will need to be investigated in future prospective trials.

Human pineal parenchymal tumors (PPTs) are rare tumors, and little is known about their molecular pathogenesis. We used Atlas plastic human 8 K microarray analysis to identify the genes expressed in four human PPTs of different grades, in normal brain tissue and in a normal fetal pineal gland. We selected the most highly expressed genes in PPT (n=39) and compared their expression to that both in normal brain and fetal pineal gland. Nine genes were expressed more than twice as strongly and 3 at about half the level in PPT. Furthermore, real-time reverse transcription-PCR was performed to compare mRNA levels in the four PPTs, in four medulloblastomas (MBs) (the most common type of similar embryonal neoplasm in the cerebellum), and in normal brain, for 9 of the 39 genes. Among genes showing an expression similar to that obtained with microarray, puromycin-sensitive aminopeptidase and teratocarcinoma-derived growth factor 3 were up-regulated in PPT and in MB, and adenomatous polyposis coli like was down-regulated only in PPT. Up-regulated expression of chromosome 17 open reading frame 1A was seen in high-grade PPT and in MB, but not in lower grade PPT. In conclusion, our results identified a number of genes that are differentially expressed in PPT and MB, and some of them may serve as prognostic markers and can be used to define mechanisms of tumorigenesis.