SNP array analysis reveals novel genomic abnormalities including copy neutral loss of heterozygosity in anaplastic oligodendrogliomas

Anaplastic oligodendrogliomas (AOD) are rare glial tumors in adults with relative homogeneous clinical, radiological and histological features at the time of diagnosis but dramatically various clinical courses. Studies have identified several molecular abnormalities with clinical or biological relevance to AOD (e.g. t(1;19)(q10;p10), IDH1, IDH2, CIC and FUBP1 mutations).

To better characterize the clinical and biological behavior of this tumor type, the creation of a national multicentric network, named “Prise en charge des OLigodendrogliomes Anaplasiques (POLA),” has been supported by the Institut National du Cancer (InCA). Newly diagnosed and centrally validated AOD patients and their related biological material (tumor and blood samples) were prospectively included in the POLA clinical database and tissue bank, respectively.

At the molecular level, we have conducted a high-resolution single nucleotide polymorphism array analysis, which included 83 patients. Despite a careful central pathological review, AOD have been found to exhibit heterogeneous genomic features. A total of 82% of the tumors exhibited a 1p/19q-co-deletion, while 18% harbor a distinct chromosome pattern. Novel focal abnormalities, including homozygously deleted, amplified and disrupted regions, have been identified. Recurring copy neutral losses of heterozygosity (CNLOH) inducing the modulation of gene expression have also been discovered. CNLOH in the CDKN2A locus was associated with protein silencing in 1/3 of the cases. In addition, FUBP1 homozygous deletion was detected in one case suggesting a putative tumor suppressor role of FUBP1 in AOD.

Our study showed that the genomic and pathological analyses of AOD are synergistic in detecting relevant clinical and biological subgroups of AOD.

Subgroup-specific structural variation across 1,000 medulloblastoma genomes

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 4α. 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-β signalling in Group 3, and NF-κB signalling in Group 4, suggest future avenues for rational, targeted therapy.

Recurrent genetic alterations in primary central nervous system lymphoma of immunocompetent patients

2023

Background: Little is known about the molecular pathogenesis of primary central nervous system lymphoma (PCNSL) in immunocompetent patients. Our objective was to identify the genetic changes involved in PCNSL oncogenesis and evaluate their clinical relevance. Methods: Twenty nine and four newly diagnosed, HIV-negative PCNSL patients were investigated using high-resolution single nucleotide polymorphism (SNPa) arrays (Infinium Illumina Human 610-Quad SNP array-Illumina; validated by real-time quantitative polymerase chain reaction) and whole-exome sequencing respectively. Molecular results were correlated with prognosis. Results: All PCNSLs were diffuse large B-cell lymphomas, and the patients received high-dose methotrexate-based polychemotherapy without radiotherapy as an initial treatment.SNPa analysis revealed recurrent large and focal chromosome imbalances that target candidate genes in PCNSL oncogenesis. The most frequent genomic changes were (i) 6p21.32 loss (79%), corresponding to the HLA locus; (ii) 6q loss (27-37%); (iii) CDKN2A homozygous deletions (45%); (iv) 12q12-q22 (27%); (v) chromosome 7q21 and 7q31 gains (20%). Sequencing of matched tumor and blood DNA samples identified novel somatic mutations in MYD88 (L265P hot spot mutation) and TBL1XR1 in 38% and 14% of the cases, respectively. The correlation of genetic abnormalities with clinical outcomes using multivariate analysis showed that 6q22 loss (p=0.006 and p=0.01), and CDKN2A homozygous deletion (p=0.02 and p=0.01) were significantly associated with shorter progression free survival and overall survival. Conclusions: Our study identified novel genetic alterations in PCNSL, such as MYD88 and TBL1XR1 somatic mutations, which would both contribute to the constitutive activation of the NFkB signaling pathway and represent potential promising targets for future therapeutic strategies.

Molecular characterization of circumventricular organs and third ventricle ependyma in the rat: potential markers for periventricular tumors

Circumventricular organs (CVOs) are specialized ventricular structures around the third and fourth ventricles of the brain. In humans, these structures are present during the fetal period and some become vestigial after birth. Some of these organs, such as the pineal gland (PG), subcommissural organ (SCO), and organum vasculosum of the lamina terminalis, might be the sites of origin of periventricular tumors, notably pineal parenchymal tumors, papillary tumor of the pineal region and chordoid glioma. In contrast to the situation in humans, CVOs are present in the adult rat and can be dissected by laser capture microdissection (LCM). In this study, we used LCM and microarrays to analyze the transcriptomes of three CVOs, the SCO, the subfornical organ (SFO), and the PG and the third ventricle ependyma in the adult rat, in order to better characterize these organs at the molecular level. Several genes were expressed only, or mainly, in one of these structures, for example, Erbb2 and Col11a1 in the ependyma, Epcam and Claudin-3 (CLDN3) in the SCO, Ren1 and Slc22a3 in the SFO and Tph, Aanat and Asmt in the PG. The expression of these genes in periventricular tumors should be examined as evidence for a possible origin from the CVOs. Furthermore, we performed an immunohistochemical study of CLDN3, a membrane protein involved in forming cellular tight junctions and found that CLDN3 expression was restricted to the apical pole of ependymocytes in the SCO. This microarray study provides new evidence regarding the possible origin of some rare periventricular tumors.

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 < 0.0001). However, there was no statistically significant difference in either overall or disease-free survival evaluated by the Kaplan-Meier method for patients with different grade tumours or Ki67 LI, possibly due to the different clinical management of patients in different centres.

CONCLUSIONS

The Ki67 LI may be a useful additional tool for grading PPTs, more particularly in small tumour samples.

Solitary fibrous tumors and hemangiopericytomas of the meninges: overlapping pathological features and common prognostic factors suggest the same spectrum of tumors

Meningeal solitary fibrous tumors (SFTs) and hemangiopericytomas (HPCs) are distinct entities in the World Health Organization (WHO) classification of central nervous system (CNS) tumors while they belong to the same spectrum of tumors in other locations. Well-defined histological prognostic factors are also lacking for these tumors. In order to clarify the relationship between SFT and HPC and to find histological and immunohistochemical prognostic factors, we carried out a retrospective study in 89 patients. The following histological parameters were recorded: hypercellularity, collagenic areas, cytonuclear atypias, necrosis, mitotic count per 10 high-power fields, vasculo-nervous adherences defined by engulfment of vessel or nerve by the tumor, brain infiltration. We found overlapping histological and immunohistochemical features between SFT and HPC. The most relevant histological prognostic factors in the whole cohort for both progression-free survival (PFS) and overall survival (OS) in univariate analysis were hypercellularity, high mitotic count (>5 per 10 high-power fields) and necrosis. On the basis of these results, we propose a new grading scheme for these tumors which was of pronostic value for both PFS and OS in uni- and multivariate analysis. As extent of surgery was also a prognostic factor for both PFS and OS in univariate analysis, we propose that management of SFT/HPC might be based both on quality of removal and histological grade.

Histopathology of tumors of the pineal region

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.

Prolonged response without prolonged chemotherapy: a lesson from PCV chemotherapy in low-grade gliomas

Previous studies with temozolomide suggest that a prolonged duration of chemotherapy is important for treating low-grade gliomas (LGGs). PCV (procarbazine, CCNU, vincristine) chemotherapy has demonstrated efficacy in treating LGGs, but this therapy cannot be used for a prolonged period because of the cumulative toxicity. The aim of the present study was to evaluate the impact of first-line PCV chemotherapy on LGGs growth kinetics. The mean tumor diameter (MTD) of 21 LGGs was measured on serial magnetic resonance images before (n=13), during, and after PCV onset (n=21). During PCV treatment, a decrease in the MTD was observed in all patients. After PCV discontinuation, an ongoing decrease in MTD was observed in 20 of the 21 patients. Median duration of the MTD decrease was 3.4 years (range, 0.8-7.7) after PCV onset and 2.7 years (range, 0-7) after the end of PCV treatment with 60% of LGGs, demonstrating an ongoing and prolonged (>2 years) response despite chemotherapy no longer being administered. According to McDonald's criteria, the rates of partial and minor responses were 5% and 38% at the end of PCV but 38% and 42% at the time of maximal MTD decrease, which occurred after a median period of 3.4 years after PCV onset. These results challenge the idea that a prolonged duration of chemotherapy is necessary for treating LGGs and raise the issue of understanding the mechanisms involved in the persistent tumor volume decrease once chemotherapy is terminated.

Adult intracranial WHO grade II ependymomas: long-term outcome and prognostic factor analysis in a series of 114 patients

Ependymomas account for 2% of all intracranial tumors in adults. Considerable controversy continues to exist with regard to their prognostic factors and therapeutic management due to the rarity and the heterogeneity of series reported so far. The authors report a retrospective study of a homogenous population of 114 adult patients harboring WHO grade II intracranial ependymomas from 32 French Neurosurgical Centers between 1990 and 2004. All clinico-radiological and follow-up data were analyzed, and a central pathologic review was performed by two confirmed neuropathologists. The 5- and 10-year overall survival (OS) rates were 86.1% and 81.0%, respectively; the 5- and 10-year progression-free survival (PFS) rates were 74.6% and 58.9%, respectively. On multivariate analysis, the OS rates were associated with preoperative KPS score (P = .027), extent of surgery (P = .008), and tumor location (supratentorial vs infratentorial, P = .012). The multivariate analysis also revealed that the risk of recurrence was associated with incomplete resection (P = .001) and supratentotrial location (P = .038). Moreover, adjuvant radiotherapy (RT) for patients with incompletely resected tumors is responsible for a significant improvement of both overall (P = .005) and progression-free (P = .002) survival. This study clearly supports the major prognostic impact of the extent of surgery in WHO grade II. Interestingly, tumor location also seems to have an actual impact on both OS and PFS. Finally, the prognostic impact of RT was found to be beneficial for incompletely resected tumors.

P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2) localize in the microvessels forming the blood-tumor barrier in ependymomas

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.

Aromatic L-amino acid decarboxylase-immunoreactive structures in human midbrain, pons, and medulla

The objective of the present study was to determine with precision the localization of neurons and fibers immunoreactive (ir) for aromatic L-amino acid decarboxylase (AADC), the second-step enzyme responsible for conversion of L-dihydroxyphenylalanine (L-DOPA) to dopamine (DA) and 5-hydroxytryptophan (5-HTP) to serotonin (5-hydroxytryptamine: 5-HT) in the midbrain, pons, and medulla oblongata of the adult human brain. Intense AADC immunoreactivity was observed in a large number of presumptive 5-HT neuronal cell bodies distributed in all of the raphe nuclei, as well as in regions outside the raphe nuclei such as the ventral portions of the pons and medulla. Moderate to strong immunoreaction was observable in presumptive DA cells in the mesencephalic reticular formation, substantia nigra, and ventral tegmental area of Tsai, as well as in presumptive noradrenergic (NA) cells, which were aggregated in the locus coeruleus and dispersed in the subcoeruleus nuclei. In the medulla oblongata, immunoreaction of moderate intensity was distributed in the mid and ventrolateral portions of the intermediate reticular nucleus, which constitutes the oblique plate of A1/C1 presumptive adrenergic and/or NA neurons. The dorsal vagal AADC-ir neurons were fewer in number and stained more weakly than cells immunoreactive for tyrosine hydroxylase (TH). AADC immunoreactivity was not identified in an aggregate of TH-ir neurons lying in the gelatinous subnucleus of the solitary nucleus, a restricted region just rostroventral to the area postrema. Nonaminergic AADC-positive neurons (D neurons), which are abundant in the rat and cat midbrain, pons, and medulla, were hardly detectable in homologous regions in the human brain, although they were clearly distinguishable in the forebrain.

Contribution of the daily melatonin profile to diagnosis of tumors of the pineal region

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.

Bcl-2 expression in a papillary tumor of the pineal region

Neuroepithelial papillary tumor of the pineal region (PTPR) has been described by several groups and recognized by the 2007 World Health Organization Classification of Tumors of the Central Nervous System. The proto-oncogen Blc-2 can function as an apoptosis suppressor and can promote neoplastic transformation. It may also be involved in neuroendocrine differentiation in some tumors. As PTPRs express neuroendocrine markers, we investigated the expression of Bcl-2 in tumoral cells of a new case of PTPR in a 42-year-old woman. Bcl-2 immunostaining was detected in the cytoplasm of the tumoral cells; staining intensity was heterogeneous from cell to cell and more intense in papillary areas. This intense expression of Bcl-2 in one case of PTPR with a high proliferation index (8%) might be related to the malignancy of this neoplasm. It will be interesting to investigate the prognosis impact of Bcl-2 expression in a large series of PTPRs.

Pineocytoma and pineal parenchymal tumors of intermediate differentiation presenting cytologic pleomorphism: a multicenter study

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.

Histological features and expression of enzymes implicated in melatonin synthesis in pineal parenchymal tumours and in cultured tumoural pineal cells

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.

[Intracranial ependymomas in adult patients. Retrospective analysis of 121 cases from the multicentric French study]

Ependymomas are rare intracranial tumors observed in adults. Prognostic factors as well as proper therapeutic management remain controversial. We report a retrospective study of 121 cases intracranial ependymomas diagnosed between 1990 and 2004 in adult patients. Mean age was 46 years with a 1/1 sex-ratio. Supratentorial and infratentorial localization was noted for 41 (33.9%) and 80 (66.1%) patients respectively. Total gross resection was achieved for 62.8% of tumors. WHO staging was grade II for 72.7% and III for 27.3%. Recurrence developed in 41 (33.9%) patients. Median follow-up was 70 months. The 5-year and 10-year overall survivals were 85 and 76% respectively; the respective progression-free survivals were 64 and 43%. At univariate analysis, age, KPS, localization, extent of surgery and histological grade were correlated with overall survival. At multivariate analysis age, location, histological grade and extent of surgery contributed most to prediction of overall survival. Concerning progression-free survival, univariate analysis found age, KPS, localization, extent of surgery, complementary treatment and histological grade to be correlated with recurrence. Multivariate analysis retained extent of surgery, histological grade and complementary treatment as the most important predictors of progression-free survival. This study demonstrated that extent of surgery and tumor grade are the two main prognostic factors in adult intracranial ependymomas with respect to overall and progression-free survival. Furthermore, our data suggest that postoperative radiotherapy significantly increases progression-free survival in patients with incompletely resected grade II tumors.

The 2007 WHO classification of tumours of the central nervous system

The fourth edition of the World Health Organization (WHO) classification of tumours of the central nervous system, published in 2007, lists several new entities, including angiocentric glioma, papillary glioneuronal tumour, rosette-forming glioneuronal tumour of the fourth ventricle, papillary tumour of the pineal region, pituicytoma and spindle cell oncocytoma of the adenohypophysis. Histological variants were added if there was evidence of a different age distribution, location, genetic profile or clinical behaviour; these included pilomyxoid astrocytoma, anaplastic medulloblastoma and medulloblastoma with extensive nodularity. The WHO grading scheme and the sections on genetic profiles were updated and the rhabdoid tumour predisposition syndrome was added to the list of familial tumour syndromes typically involving the nervous system. As in the previous, 2000 edition of the WHO ‘Blue Book’, the classification is accompanied by a concise commentary on clinico-pathological characteristics of each tumour type. The 2007 WHO classification is based on the consensus of an international Working Group of 25 pathologists and geneticists, as well as contributions from more than 70 international experts overall, and is presented as the standard for the definition of brain tumours to the clinical oncology and cancer research communities world-wide.

The 2007 WHO classification of tumours of the central nervous system

The fourth edition of the World Health Organization (WHO) classification of tumours of the central nervous system, published in 2007, lists several new entities, including angiocentric glioma, papillary glioneuronal tumour, rosette-forming glioneuronal tumour of the fourth ventricle, papillary tumour of the pineal region, pituicytoma and spindle cell oncocytoma of the adenohypophysis. Histological variants were added if there was evidence of a different age distribution, location, genetic profile or clinical behaviour; these included pilomyxoid astrocytoma, anaplastic medulloblastoma and medulloblastoma with extensive nodularity. The WHO grading scheme and the sections on genetic profiles were updated and the rhabdoid tumour predisposition syndrome was added to the list of familial tumour syndromes typically involving the nervous system. As in the previous, 2000 edition of the WHO 'Blue Book', the classification is accompanied by a concise commentary on clinico-pathological characteristics of each tumour type. The 2007 WHO classification is based on the consensus of an international Working Group of 25 pathologists and geneticists, as well as contributions from more than 70 international experts overall, and is presented as the standard for the definition of brain tumours to the clinical oncology and cancer research communities world-wide.

The 2007 WHO classification of tumours of the central nervous system

The fourth edition of the World Health Organization (WHO) classification of tumours of the central nervous system, published in 2007, lists several new entities, including angiocentric glioma, papillary glioneuronal tumour, rosette-forming glioneuronal tumour of the fourth ventricle, papillary tumour of the pineal region, pituicytoma and spindle cell oncocytoma of the adenohypophysis. Histological variants were added if there was evidence of a different age distribution, location, genetic profile or clinical behaviour; these included pilomyxoid astrocytoma, anaplastic medulloblastoma and medulloblastoma with extensive nodularity. The WHO grading scheme and the sections on genetic profiles were updated and the rhabdoid tumour predisposition syndrome was added to the list of familial tumour syndromes typically involving the nervous system. As in the previous, 2000 edition of the WHO 'Blue Book', the classification is accompanied by a concise commentary on clinico-pathological characteristics of each tumour type. The 2007 WHO classification is based on the consensus of an international Working Group of 25 pathologists and geneticists, as well as contributions from more than 70 international experts overall, and is presented as the standard for the definition of brain tumours to the clinical oncology and cancer research communities world-wide.

The 2007 WHO classification of tumours of the central nervous system

The fourth edition of the World Health Organization (WHO) classification of tumours of the central nervous system, published in 2007, lists several new entities, including angiocentric glioma, papillary glioneuronal tumour, rosette-forming glioneuronal tumour of the fourth ventricle, papillary tumour of the pineal region, pituicytoma and spindle cell oncocytoma of the adenohypophysis. Histological variants were added if there was evidence of a different age distribution, location, genetic profile or clinical behaviour; these included pilomyxoid astrocytoma, anaplastic medulloblastoma and medulloblastoma with extensive nodularity. The WHO grading scheme and the sections on genetic profiles were updated and the rhabdoid tumour predisposition syndrome was added to the list of familial tumour syndromes typically involving the nervous system. As in the previous, 2000 edition of the WHO 'Blue Book', the classification is accompanied by a concise commentary on clinico-pathological characteristics of each tumour type. The 2007 WHO classification is based on the consensus of an international Working Group of 25 pathologists and geneticists, as well as contributions from more than 70 international experts overall, and is presented as the standard for the definition of brain tumours to the clinical oncology and cancer research communities world-wide.

The 2007 WHO classification of tumours of the central nervous system

The fourth edition of the World Health Organization (WHO) classification of tumours of the central nervous system, published in 2007, lists several new entities, including angiocentric glioma, papillary glioneuronal tumour, rosette-forming glioneuronal tumour of the fourth ventricle, papillary tumour of the pineal region, pituicytoma and spindle cell oncocytoma of the adenohypophysis. Histological variants were added if there was evidence of a different age distribution, location, genetic profile or clinical behaviour; these included pilomyxoid astrocytoma, anaplastic medulloblastoma and medulloblastoma with extensive nodularity. The WHO grading scheme and the sections on genetic profiles were updated and the rhabdoid tumour predisposition syndrome was added to the list of familial tumour syndromes typically involving the nervous system. As in the previous, 2000 edition of the WHO 'Blue Book', the classification is accompanied by a concise commentary on clinico-pathological characteristics of each tumour type. The 2007 WHO classification is based on the consensus of an international Working Group of 25 pathologists and geneticists, as well as contributions from more than 70 international experts overall, and is presented as the standard for the definition of brain tumours to the clinical oncology and cancer research communities world-wide.

The 2007 WHO classification of tumours of the central nervous system

The fourth edition of the World Health Organization (WHO) classification of tumours of the central nervous system, published in 2007, lists several new entities, including angiocentric glioma, papillary glioneuronal tumour, rosette-forming glioneuronal tumour of the fourth ventricle, papillary tumour of the pineal region, pituicytoma and spindle cell oncocytoma of the adenohypophysis. Histological variants were added if there was evidence of a different age distribution, location, genetic profile or clinical behaviour; these included pilomyxoid astrocytoma, anaplastic medulloblastoma and medulloblastoma with extensive nodularity. The WHO grading scheme and the sections on genetic profiles were updated and the rhabdoid tumour predisposition syndrome was added to the list of familial tumour syndromes typically involving the nervous system. As in the previous, 2000 edition of the WHO 'Blue Book', the classification is accompanied by a concise commentary on clinico-pathological characteristics of each tumour type. The 2007 WHO classification is based on the consensus of an international Working Group of 25 pathologists and geneticists, as well as contributions from more than 70 international experts overall, and is presented as the standard for the definition of brain tumours to the clinical oncology and cancer research communities world-wide.

[Cerebral amyloid angiopathy]

Cerebral amyloid angiopathy (CAA) is characterized by deposition of cerebrovascular amyloid protein in the media of leptomeningeal vessels. (amyloid B protein, cystatin C, transthyretin, gelsolin, and prion protein). It is a cause of cerebrovascular disorders including cerebral hemorrhage, cognitive impairment and unusually transient neurological symptoms. It is the main contributing factor to cerebral hemorrhage after hypertension in the elderly. We aimed to review epidemiological, pathophysiological and clinical and MRI imaging data in CAA.

Phase II study of the combination of cisplatin + temozolomide in malignant glial tumours in children and adolescents at diagnosis or in relapse (cistem2/nct00147160)

9543

Background: Temozolomide has been shown moderately effective in pediatric high-grade glioma (HGG). By decreasing the activity of MGMT, principal mechanism of resistance to temozolomide, cisplatin may increase the activity of this alkylating agent. Methods: Patients aged 4 to 21y with HGG outside the brainstem were treated at diagnosis or at relapse every 28 days with a combination of cisplatin 80 mg/m2 intravenously on day-1 and temozolomide 200 mg/m2 orally on days 2–6, according to the pediatric phase I recommendations. Patients treated at diagnosis had to proceed to involved field radiotherapy after the chemotherapy window. According to initial response, patients were offered additional courses, up to seven. We considered that this combination would be of interest if the response rate was superior or equal to 20%, using a two-stage Simon design in 3 cohorts: evaluable non measurable (infiltrative) at diagnosis (cohort A1); measurable disease (nodular) at diagnosis (A2); recurrent disease (B). The primary endpoint was complete or partial response after two courses, confirmed by central review. Up to 29 evaluable pts were to be entered in each cohort. If fewer than 4/29 responses were observed, it would be concluded that the combination is ineffective. Results: 56 pts were entered from 10/2003 through 07/2006 in 25 centers. One was excluded after central pathology review and 3 due to insufficient radiology work-out. 42 had grade III and 13 grade IV gliomas, including 21 tumors with oligodendroglial features. No response was observed in the first 11 pts in cohort A1 and in the first 12 pts in cohort B. Two partial and 4 minor responses were confirmed in 29 pts of cohort A2 leading to a 7% response rate (95% CI, 1–23%). Median time to progression was 1.7, 7.1 and 6.9 months in cohorts A1, A2 and B, respectively. Toxicity was manageable except in pts with large infiltrative lesions who did not tolerate hydration. Conclusion: CISTEM combination has insufficient efficacy in pediatric compared to adult HGG despite efficient down-regulation of MGMT activity. To overcome resistance to temozolomide in children and adolescents, one may need to target other known resistance mechanisms such as mismatch-repair deficiency.

[Table: see text]

Role of exclusive chemotherapy as first line treatment in oligodendroglioma

PURPOSE

The optimal therapy of oligodendrogliomas remains uncertain. Although chemosensitive, these tumors are not chemocurable. We investigated whether chemotherapy delays the need for radiation therapy (RT) without decreasing length and quality of survival.

METHODS AND MATERIALS

Among 89 patients treated for oligodendrogliomas at the Centre Léon Bérard of Lyon from 1982 to 1999, 59 patients fitted inclusion criteria, having had centrally reviewed pure oligodendroglioma requiring treatment. According to the WHO's classification 35 patients had Grade III and 24, Grade II oligodendrogliomas.

RESULTS

According to the intent to treat, patients were retrospectively classified in three groups as exclusive RT (Group 1), radio-chemotherapy (Group 2), or exclusive chemotherapy (Group 3). Median progression-free survival (PFS): was 47 months [95% confidence interval (CI) 39-56], and median overall survival (OS) was 109 months (95% CI 83-134). In univariate analysis, PFS was correlated with frontal location and WHO classification; OS was correlated with frontal location and Post-operative Karnosky performans status both appearing as independent prognostic factors for OS in multivariate analysis. There was no significant difference between the treatment groups with regard to PFS (P = 0.82) and OS (P = 0.64). In the group of patients treated with exclusive chemotherapy the 5-year PFS and OS rates were 44 and 71%, respectively.

CONCLUSION

Front-line exclusive chemotherapy results in prolonged OS in patients with confirmed pure oligodendroglioma. Whether this strategy improves quality of life remains debatable.

Reactive perivascular T-cell infiltrate predicts survival in primary central nervous system B-cell lymphomas

Well-established histopathological prognostic factors are lacking in primary central nervous system (CNS) lymphomas (PCNSL). The present study investigated the presence and prognostic role of tumour necrosis (TN) and reactive perivascular T-cell infiltrate (RPVI), defined as a rim of small reactive T-lymphocytes occurring alone or located between the vascular wall and large neoplastic cells, in tumour samples from 100 immunocompetent patients with PCNSL. World Health Organization histotypes of the patients were: 96 diffuse large B-cell lymphomas, two Burkitt-like lymphomas, one anaplastic large T-cell lymphoma and one unclassified B-cell lymphoma. TN was observed in 24 (24%) cases and RPVI in 26 (36%) of 73 assessable cases. Patients with RPVI-positive lesions exhibited a significantly better overall survival (OS) than patients with RPVI-negative lymphoma, particularly among patients treated with high-dose methotrexate-based chemotherapy (3-year OS: 59 +/- 14% vs. 42 +/- 9%, P = 0.02). By contrast, the presence of TN did not demonstrate prognostic significance. Multivariate analysis confirmed an independent association between RPVI and survival. In conclusion, the presence of RPVI is independently associated with survival in PCNSL. This parameter can be easily and routinely assessed at diagnosis on histopathological specimens.

Épendymomes intracrâniens de l'adulte. Diagnostic histologique et facteurs histopronostiques

BACKGROUND

Intracranial ependymomas are rare in adults and histopathological prognostic factors are poorly determined.

PURPOSE

A retrospective multicentric study was conducted in France in order to assess the prognostic value of histology.

MATERIAL

Between 1990 and 2004, 216 adult patients with newly diagnosed ependymomas were treated in 19 French centers. Eligibility required institutional histopathological confirmation of an ependymoma and available clinical history and MRI features (see comparison paper).

METHODS

Histological preparations and one paraffin embedded block from each patient were sent to Pr D. Figarella-Branger in Marseille. Central review by four neuropathologists (D. Figarella-Branger, A. Maues de Paula, C. Fernandez and A. Jouvet) was performed. Specimens for which all pathologists agreed with the histological diagnosis of ependymomas were included, whereas cases for which all disagree were excluded and reclassified. In the event of doubt and/or discrepancies between pathologists immunostaining was performed in order to reach a consensus diagnosis. Diagnostic of ependymomas was confirmed in 121 cases (56%). In theses cases, ependymomas were classified according to the WHO system (subtype and grade). The potential prognostic value (overall survival OS and disease free survival DFS) of the following histological parameters was examined: perivascular pseudorosettes, ependymal rosettes, hyalinized vessels, mitotic index, microvascular proliferation, necrosis, area of increased cellularity, nuclear atypia, brain invasion and Mib-1 labelling index.

RESULTS

Among the 121 ependymomas, 88 were grade II (47 classic, 17 cellular, 2 papillar, 6 clear cells and 16 tanicytic) and 33 grade III. WHO grading, occurrence of microvascular proliferation, necrosis, nuclear atypia and high proliferative index were correlated with both OS and DFS. Moreover, quantification of certain parameters enabled a reproducible grading system correlated with both OS and DFS.

Multicentric French study on adult intracranial ependymomas: prognostic factors analysis and therapeutic considerations from a cohort of 152 patients

Ependymomas account for 2% of all intracranial tumours in adults. Considerable controversy continues to exist with regard to their prognostic factors and therapeutic management due to the rarity and the heterogeneity of series reported so far. The authors report a retrospective study of a homogenous population of 152 adult patients harbouring intracranial ependymomas from 24 French Neurosurgical Centres between 1990 and 2004. All clinico-radiological and follow-up data were analysed and a central pathologic review was performed by two confirmed neuropathologists. The 5- and 10-year overall survival rates were 84.8 and 76.5%, respectively; the 5- and 10-year progression-free survival rates were 63.5 and 52.8%, respectively. On multivariate analysis, overall survival rates were associated with histological grade (P < 0.001), extent of surgery (P = 0.006), patient age (P = 0.004) and patient Karnofski performance status (P = 0.03). The multivariate analysis also revealed that the risk of recurrence was associated with high histological grade (P < 0.001), incomplete resection (P < 0.001) and Karnofski performance status < or = 80 (P = 0.04). The impact of radiotherapy was found to be beneficial for incompletely resected low-grade ependymomas and to a lesser extent for completely removed high-grade tumours. In association with Karnofski performance status and extent of surgery, histological grade is a major prognostic factor in adult intracranial ependymomas. The application of a simple and reproducible grading scheme using objective anaplastic criteria seems useful practically and clinically applicable. The role of adjuvant radiotherapy for patients with incompletely resected low-grade ependymomas seems to be beneficial but remains to be addressed for high-grade tumours.