Xanthogranuloma, Rathke's cyst, and childhood craniopharyngioma: results of prospective multinational studies of children and adolescents with rare sellar malformations.

CONTEXT: Craniopharyngioma (CP), Rathke's cyst (RC), and xanthogranuloma (XG) are closely related rare sellar masses. Treatment strategies in children lack consensus. OBJECTIVE: Our objective was to study clinical manifestations and treatment-related outcome in RC, XG, and CP patients. DESIGN: We conducted a multicenter surveillance trial. PATIENTS: Inclusion criteria were 1) histological diagnosis of CP, XG, or RC and 2) diagnosis at age of 18 yr or less. A total of 117 CP, 14 XG (2001-2006), and 14 RC (1996-2006) were recruited. MAIN OUTCOME: Overall survival (OS), event-free survival (EFS), and quality of life (QoL) were evaluated. RESULTS: The 5-yr OS rates were 1.00 ± 0.00 in RC and XG and 0.97 ± 0.02 in CP. The 5-yr EFS rates were 0.85 ± 0.10 in RC, 1.00 ± 0.00 in XG, and 0.50 ± 0.05 in CP. Surgical resection of XG results in complete remission without recurrence. Recurrences occur in RC (14%) and CR (59%) but can be efficiently treated by irradiation, reoperation, and/or intracystic treatment. Severe hypothalamic sequelae such as obesity and others affecting QoL are predominant in CP due to presurgical involvement (59%) and postsurgical lesions (44%) of posterior hypothalamic structures. Centers with lower neurosurgery patient load use more radical surgical approaches to treat CP, resulting in higher rates of obesity and reduced QoL. Despite 46% anterior hypothalamic involvement, severe obesity is not encountered in XG. CONCLUSIONS: Treatment of choice in XG and RC is radical surgery. In CP involving hypothalamic structures, less radical surgical approaches preserving hypothalamic integrity are recommended. Due to frequent relapses, regular imaging during follow-up is recommended for CP and RC. Treatment of patients with sellar masses should be confined to experienced multidisciplinary teams.

Serum levels of cytokines, glucose, and hemoglobin as possible predictors of poststroke depression, and association with poststroke fatigue.

Depression is a frequent and potentially disabling sequela of stroke. In the present study, we investigated the ability of stroke type, infarct volume, and laterality, and the levels of various cytokines and other blood components in the acute phase of acute ischemic stroke (AIS) in 45 patients, to predict the level of depression (Beck Depression Inventory [BDI] score) at 6, 12, and 18 months after its onset. The BDI score at 12 months poststroke was positively correlated with the acute serum level of glucose (r = 0.32, p = .038). When excluding the patients using antidepressants, the correlation between glucose level and later depression became significant at all three time points. A general association was found between depression and fatigue. Novel findings are that high acute serum levels of glucose may predict depression after AIS, a glucose level of approximately 126 mg/dL at admission might be a critical limit. Furthermore, depression and fatigue are two generally related-although independent-sequelae of stroke. Our findings did not support a causal immunological etiology for poststroke depression (PSD), as has been suggested previously for poststroke fatigue (PSF) in the same study sample.

Post-operative hypothalamic lesions and obesity in childhood craniopharyngioma: results of the multinational prospective trial KRANIOPHARYNGEOM 2000 after 3-year follow-up.

BACKGROUND: Hypothalamic obesity has major impact on prognosis and quality of life (QoL) in childhood craniopharyngioma. PATIENTS AND METHODS: For this study, 120 patients were prospectively recruited during 2001 and 2007 and evaluated after 3 years of follow-up (KRANIOPHARYNGEOM 2000). Body mass index (BMI) and QoL at diagnosis and 36 months after diagnosis were analysed based on the reference assessment of tumour localisation and post-surgical hypothalamic lesions. Treatment was analysed based on the neurosurgical strategy of 50 participating neurosurgical centres, the centre size based on the patient load. RESULTS: BMI SDS at diagnosis was similar in patients with or without hypothalamic involvement. Surgical lesions of anterior and posterior hypothalamic areas were associated with higher increase in BMI SDS during 36 months post-diagnosis compared with patients without or only anterior lesion (+1.8 BMISD, P=0.033, +2.1 BMISD; P=0.011), negative impact on QoL in patients with posterior hypothalamic lesions. Surgical strategies varied among the 50 neurosurgical centres (three large-sized, 24 middle-sized and 23 small-sized centres). Patients treated in small-sized centres presented with a higher rate of hypothalamic involvement compared with those treated in the middle- and large-sized centres. Treatment in large-sized centres was less radical, and the rates of complete resection and hypothalamic surgical lesions were lower in large-sized centres than those of the middle- and small-sized centres. However, a multivariable analysis showed that pre-operative hypothalamic involvement was the only independent risk factor for severe obesity (P=0.002). CONCLUSIONS: Radical neurosurgical strategies leading to posterior hypothalamic lesions are not recommended due to the potential to exacerbate hypothalamic obesity and impaired QoL. Treatment should be confined to experienced multidisciplinary teams.

Serum cytokine and glucose levels as predictors of poststroke fatigue in acute ischemic stroke patients.

Fatigue is a common but often overlooked symptom after stroke. This study investigated whether stroke type, infarct volume, and laterality, as well as the levels of various cytokines and other blood components in the acute phase of acute ischemic stroke (AIS), can predict the level of fatigue at 6, 12, and 18 months after its onset. In 45 patients with acute stroke, serum levels of C-reactive protein, hemoglobin, glucose, and 13 cytokines were measured within 72 h of stroke onset. The cytokine measurements were performed using BioPlex XMap technology (Luminex). The acute serum levels of interleukin (IL)-1ß and glucose were positively correlated with the score on the Fatigue Severity Scale (FSS) at 6 months after the stroke (r = 0.37, p = 0.015, and r = 0.37, p = 0.017, respectively). The acute serum levels of IL-ra and IL-9 were negatively correlated with FSS score at 12 months after the stroke (r = -0.38, p = 0.013, and r = -0.36, p = 0.019, respectively). The FSS score at 12 months after stroke was significantly lower in patients with radiologically confirmed infarction than in those without such confirmation (p = 0.048). The FSS score at 18 months was not correlated with any of the measured variables. High acute serum levels of glucose and IL-1ß, and low IL1-ra and IL-9 may predict fatigue after AIS, indicating that the development of poststroke fatigue can be accounted for by the proinflammatory response associated with AIS. These novel findings support a new cytokine theory of fatigue after stroke. However, more research is needed to validate the results of this study.

Serum levels of cytokines and C-reactive protein in acute ischemic stroke patients, and their relationship to stroke lateralization, type, and infarct volume.

There is increasing evidence that inflammation plays an important role in the progression of acute ischemic stroke (AIS). The primary aims of this study were to examine the serum levels of 13 cytokines, C-reactive protein (CRP), glucose, and hemoglobin in AIS patients, and their relationship to stroke lateralization, type, and infarct volume. Forty-five patients with AIS were evaluated. Blood samples were taken within 72 h, and volumetric analyses performed within 1-7 days after AIS onset. Cytokines were measured in serum from all patients and from 40 control subjects using Luminex Bio-Plex XMap technology. The levels of interleukin (IL)-1ra (p < 0.001), IL-6 (p < 0.001), IL-8 (p < 0.001), IL-9 (p = 0.038), IL-10 (p = 0.001), IL-12 (p = 0.001), IL-18 (p < 0.001), and GRO-α (CXCL1) (p = 0.017) were significantly higher in the AIS patients than in the controls. The IL-8 level was significantly correlated with age in the patient group (r = 0.52, p < 0.001). None of the variables were found to be associated with stroke lateralization. Infarct volume was significantly positively correlated with CRP level (r = 0.47, p = 0.005). Patients with radiologically confirmed infarctions had significantly elevated serum levels of GRO-α (p = 0.023). The cytokine profile of the AIS patients supports not only earlier findings of a proinflammatory response but also early activation of endogenous immunosuppressive mechanisms. Novel findings of this study are elevated serum levels of IL-9 and GRO-α. Elevated GRO-α in AIS patients with radiologically confirmed infarctions suggests that GRO-α is specific for stroke of known etiology. Our results indicate that CRP plays an important role in the progression of cerebral tissue injury.

Analyses of treatment variables for patients with childhood craniopharyngioma--results of the multicenter prospective trial KRANIOPHARYNGEOM 2000 after three years of follow-up.

BACKGROUND: Controversies surround various treatment variables for patients with childhood craniopharyngioma such as growth hormone (GH) replacement, which some believe can exacerbate recurrence/progression. We prospectively assessed the risk of tumor recurrence/progression in survivors of childhood craniopharyngioma. METHODS: Multivariable analyses of risk factors (age at diagnosis, degree of resection, irradiation, GH treatment and gender) and descriptive analyses of overall survival (OS) and event-free survival (EFS) rates were performed in 117 patients, recruited prospectively and evaluated after 3 years of follow-up in the German, Austrian and Swiss multicenter trial KRANIOPHARYNGEOM 2000. RESULTS: We observed a 3-year OS of 0.97 and a 3-year EFS of 0.46, indicating high recurrence rates after complete resection (CR) (n = 47; 3-year-EFS: 0.64) and high progression rates after incomplete resection (IR) (n = 64; 3-year EFS: 0.31). The risk of an event decreased by 80% after CR compared to IR (hazard ratio = 0.20; p < 0.001). Irradiation had protective effects on EFS: irradiated patients had an 88% lower risk of recurrence/progression compared to patients without/before irradiation (hazard ratio = 0.12; p < 0.001). GH treatment had no impact on 3-year EFS rates. CONCLUSIONS: Tumor recurrences/progressions are frequent and occur early after initial treatment of childhood craniopharyngioma. A radical resection preserving the integrity of hypothalamic structures appears optimal at original diagnosis. Irradiation was efficient in preventing recurrences/progressions. GH treatment had no impact on the low 3-year EFS observed in our study. However, further conclusions on the influence of GH on recurrence rates have to be refined to long-term follow-up studies of patients with childhood craniopharyngioma.

Hypothalamic papillary tumor in a patient with tuberous sclerosis.

We here report an unusual tumor of the suprasellar region featuring a papillary growth pattern and cytokeratin expression in a 10-year-old boy with tuberous sclerosis. This hitherto undescribed low-grade hypothalamic tumor extends the spectrum of tumors associated with the tuberous sclerosis complex.

Modification of milk and whey surface properties by enzymatic hydrolysis of milk phospholipids.

Phospholipase A1 were shown to improve foaming properties of skim milk and whey, implying that phospholipases can be useful tools for modifying the functionality of dairy products and ingredients. The ability of three fungal phospholipases and porcine pancreatic phospholipase A2 to hydrolyze milk phospholipids was investigated by using sodium deoxycholate-solubilized milk phospholipid and whole milk. The enzyme with the highest activity in milk was Fusarium venenatum phospholipase A1. Milk and whey were subsequently characterized using tensiometry and interfacial shear rheology. The lysophospholipids released from the fat globule membrane decreased the surface tension of skim milk and whey. A dramatic decrease in the surface shear viscous and elastic moduli indicated a shift from a protein-dominated to a surfactant-dominated interface. The surface shear moduli did not correlate with the foam stability, which was improved by phospholipase A1.

Secondary narcolepsy may be a causative factor of increased daytime sleepiness in obese childhood craniopharyngioma patients.

Prognosis in childhood craniopharyngioma survivors hinges upon late effects such as pituitary deficiency and obesity. Observations indicate that reduced physical activity and increased daytime sleepiness might be risk factors for obesity. We analyzed the degree of daytime sleepiness in 115 childhood craniopharyngioma patients (47% obese) using the Epworth Sleepiness Scale (ESS). Thirty-five (30%) displayed increased daytime sleepiness (ESS score > 10) of whom 14 were obese (26% of obese cohort). Polysomnography (PSG) and Multiple Sleep Latency Tests (MSLT) were conducted with 10 obese patients presenting increased daytime sleepiness, with only two craniopharyngioma patients revealing a sleep related breathing disorder. Four patients had repeated episodes of SOREM (sleep onset rapid eye movement), the classic PSG criterion for narcolepsy. Three patients displayed hypersomnia. All but one patient qualified as acutely obese. We speculate that secondary narcolepsy is an exacerbating condition of childhood craniopharyngioma obesity, supported by recent reports on orexin and narcolepsy which suggest hypothalamic failure in idiopathic narcolepsy.

Phosphatidylinositol 3'-kinase/AKT signaling is activated in medulloblastoma cell proliferation and is associated with reduced expression of PTEN.

PURPOSE: Medulloblastomas represent the most frequent malignant brain tumors of childhood. They are supposed to originate from cerebellar neural precursor cells. Recently, it has been shown that Sonic Hedgehog-induced formation of medulloblastoma in an animal model is significantly enhanced by activation of the phosphatidylinositol 3'-kinase (PI3K) signaling pathway. EXPERIMENTAL DESIGN: To examine a role for PI3K/AKT signaling in the molecular pathogenesis of human medulloblastoma, we did an immunohistochemical study of the expression of Ser473-phosphorylated (p)-AKT protein in 22 medulloblastoma samples: All samples displayed p-AKT expression. To investigate if an activated PI3K/AKT pathway is required for medulloblastoma cell growth, we treated five human medulloblastoma cell lines with increasing concentrations of the PI3K inhibitor LY294002 and analyzed cellular proliferation and apoptosis. The antiproliferative effect could be antagonized by overexpressing constitutively active AKT. As the activation of PI3K/AKT signaling may be associated with alterations of the PTEN gene located at 10q23.3, a chromosomal region subject to frequent allelic losses in medulloblastoma, we screened PTEN for mutations and mRNA expression. RESULTS: Proliferation of all of the medulloblastoma cell lines was dependent on PI3K/AKT signaling, whereas apoptosis was not prominently affected. Allelic loss was detected in 16% of the cases. One medulloblastoma cell line was found to carry a truncating mutation in the PTEN coding sequence. Even more important, PTEN mRNA and protein levels were found to be significantly lower in medulloblastomas compared with normal cerebellar tissue of different developmental stages. Reduction of PTEN expression was found to be associated with PTEN promoter hypermethylation in 50% of the tumor samples. CONCLUSIONS: We conclude that activation of the PI3K/AKT pathway constitutes an important step in the molecular pathogenesis of medulloblastoma and that dysregulation of PTEN may play a significant role in this context.

Melatonin treatment in obese patients with childhood craniopharyngioma and increased daytime sleepiness.

Craniopharyngioma is a rare dysontogenetic benign tumor. Patients frequently suffer from endocrine deficiencies, sleep disturbances and obesity due to pituitary and hypothalamic lesions. A self-assessment daytime sleepiness questionnaire (German version of the Epworth Sleepiness Scale [ESS]) was used to evaluate 79 patients with childhood craniopharyngioma. Because hypothalamic lesions may explain daytime sleepiness in craniopharyngioma patients, salivary melatonin and cortisol concentrations were examined in severely obese (BMI>or=4SD) and non severely obese (BMI<4SD) craniopharyngioma patients (n=79), patients with hypothalamic pilocytic astrocytoma (n=19), and control subjects (n=30). Using a general linear model procedure analyzing the influence of BMI and tumor diagnosis on diurnal salivary melatonin we found that morning salivary melatonin levels were related to BMI (F test: p-value=0.004) and tumor diagnosis (F-test: p-value=0.032). Also for nighttime salivary melatonin levels significant relations with BMI (p-value in F-test: <0.001) and tumor diagnosis (p-value in F-test: 0.025) were detectable. Melatonin concentrations in saliva of craniopharyngioma patients collected at nighttime or in the morning showed a negative correlation (Spearman's rho: -0.42; p=0.001; Spearman's rho: -0.31; p=0.020) with the patient's ESS score. Severely obese craniopharyngioma patients and severely obese hypothalamic tumor patients had similar patterns of melatonin secretion. Differences in terms of diurnal salivary cortisol concentrations were not detectable when patient groups and controls were compared. As decreased nocturnal melatonin levels were associated with increased daytime sleepiness, BMI and hypothalamic tumor diagnosis, we initiated an experimental melatonin substitution in 10 adult obese patients (5f/5m) with childhood craniopharyngioma. In all 10 patients with childhood craniopharyngioma the degree of daytime sleepiness significantly improved based on activity diaries, ESS, self assessment questionnaires and actimetry. We speculate that hypothalamic lesions might be responsible for both obesity and daytime sleepiness. As first experiences with experimental melatonin substitution were promising, further randomized double-blinded studies on the beneficial effects of melatonin substitution on daytime sleepiness and weight control in these patients are warranted.

Saethre-Chotzen syndrome caused by TWIST 1 gene mutations: functional differentiation from Muenke coronal synostosis syndrome.

The Saethre-Chotzen syndrome (SCS) is an autosomal dominant craniosynostosis syndrome with uni- or bilateral coronal synostosis and mild limb deformities. It is caused by loss-of-function mutations of the TWIST 1 gene. In an attempt to delineate functional features separating SCS from Muenke's syndrome, we screened patients presenting with coronal suture synostosis for mutations in the TWIST 1 gene, and for the Pro250Arg mutation in FGFR3. Within a total of 124 independent pedigrees, 39 (71 patients) were identified to carry 25 different mutations of TWIST 1 including 14 novel mutations, to which six whole gene deletions were added. The 71 patients were compared with 42 subjects from 24 pedigrees carrying the Pro250Arg mutation in FGFR3 and 65 subjects from 61 pedigrees without a detectable mutation. Classical SCS associated with a TWIST 1 mutation could be separated phenotypically from the Muenke phenotype on the basis of the following features: low-set frontal hairline, gross ptosis of eyelids, subnormal ear length, dilated parietal foramina, interdigital webbing, and hallux valgus or broad great toe with bifid distal phalanx. Functional differences were even more important: intracranial hypertension as a consequence of early progressive multisutural fusion was a significant problem in SCS only, while mental delay and sensorineural hearing loss were associated with the Muenke's syndrome. Contrary to previous reports, SCS patients with complete loss of one TWIST allele showed normal mental development.

Longitudinal study on quality of life in 102 survivors of childhood craniopharyngioma.

OBJECTS: We longitudinally analysed functional capacity and quality of life (QoL) in 102 patients with a childhood craniopharyngioma during follow-up. METHODS: The Fertigkeitenskala Münster-Heidelberg (FMH) ability scale was used for QoL assessment. Multivariate analysis evaluated FMH scores at various time points, examining hypothalamus involvement (HI), body mass index (BMI), degree of resection, tumour progression, relapse and irradiation. RESULTS AND CONCLUSION: Patients without HI (n=60) self-assessed higher QoL at baseline (p=0.001) and follow-up (p<0.001) than patients with HI (n=42). Only patients without HI evaluated at baseline >12 months after diagnosis showed longitudinal improvement in FMH scores (p=0.040). Rates of incomplete resection and irradiation were higher (p=0.070 and p=0.002 respectively) in patients with HI. In multivariate analysis, only HI, tumour relapse, progression, baseline FMH score, and time between diagnosis and baseline evaluation had independent impact on QoL. HI, tumour progression, and relapse had long-term QoL affects-most notably, severe obesity.

Functional capacity and body mass index in patients with sellar masses--cross-sectional study on 403 patients diagnosed during childhood and adolescence.

RATIONALE: We analyzed the impact of tumour localization and histology on functional capacity (FC) and body mass index (BMI) in children with sellar masses. METHODS: FC was evaluated using the ability scale Fertigkeitenskala Münster-Heidelberg in 403 children and adolescents with sellar masses (276 craniopharyngioma, 14 germinoma, 21 optic/chiasmatic glioma, 40 hypothalamic glioma, 13 cysts of Rathke's cleft and 39 other sellar masses). Besides tumour localization, the influence of gender, irradiation and age at diagnosis and at evaluation on FC and BMI was analyzed. General linear models with explanatory influential variables were built. RESULTS: In multivariate analysis, only age at diagnosis (p<0.001) and hypothalamic involvement (p=0.005) had relevant impact on FC. The second model showed BMI at diagnosis (p<0,001), hypothalamic involvement (p<0.001) and craniopharyngioma (p=0,004) to influence BMI at the latest evaluation. CONCLUSION: We conclude that hypothalamic involvement and young age at diagnosis had major impact on FC and BMI and should be considered as risk factors for impaired rehabilitation.

Subtype-specific expression and genetic alterations of the chemokinereceptor gene CXCR4 in medulloblastomas.

Recent findings indicate that the chemokine receptor Cxcr4 is essential for normal development of the cerebellar cortex. As medulloblastomas (MBs), the most common malignant brain tumors of childhood, are believed to arise from neuronal cerebellar precursors, we asked whether there is a potential role for Cxcr4 in the pathogenesis of MB. RT-PCR and immunohistochemistry revealed expression of Cxcr4 in different variants of MBs. Whereas 18/20 classic MBs showed very low levels of CXCR4 mRNA, high amounts were expressed in 17/18 desmoplastic and 6/7 extensively nodular MBs. In addition, a significant correlation of high CXCR4 mRNA levels and presence of the neurotrophin receptor p75NTR or expression of ATOH1 and GLI1 suggests that CXCR4 is a reliable marker for tumors derived from the cerebellar external granular layer. Because Cxcr4 is important for migration and cell cycle control of granular precursors, we screened for mutations in the coding region by SSCP and gene sequencing. In a series of 90 MBs and 8 MB cell lines, we found one germline and one somatic mutation resulting in amino acid substitutions in the first (Ile53Leu) and second (Asp97Asn) transmembrane regions, respectively. These data suggest that Cxcr4 may be involved in the pathogenesis of MBs.

Current strategies in diagnostics and endocrine treatment of patients with childhood craniopharyngioma during follow-up--recommendations in KRANIOPHARYNGEOM 2000.

Craniopharyngiomas are rare dysontogenetic malformations. As the survival rate after craniopharyngioma diagnosed during childhood and adolescence is high, prognosis and quality of life (QoL) in survivors mainly depend on adverse late effects such as hypopituitarism and obesity. Appropriate laboratory diagnostics of endocrine deficiencies and sufficient hormonal substitution have significant impact on prognosis and QoL. In order to evaluate and standardize diagnostic and therapeutical strategies in childhood craniopharyngioma the prospective multicenter surveillance study KRANIOPHARYNGEOM 2000 was initiated for patients diagnosed with craniopharyngioma during childhood and adolescence. We are reporting on current strategies for laboratory diagnostics and endocrine substitution in patients with childhood craniopharyngioma recruited in KRANIOPHARYNGEOM 2000.

Longitudinal study on growth and body mass index before and after diagnosis of childhood craniopharyngioma.

We analyzed whether childhood craniopharyngioma predisposes to obesity and growth impairment. Height/length, body mass index (BMI), and hypothalamic involvement were evaluated in 90 patients at standardized ages and time points before, after, and at the time of diagnosis. Relevant decreases in height sd score (SDS) started at 10-12 months of age and persisted until diagnosis of childhood craniopharyngioma. Relevant increases in BMI SDS were detectable between 4 and 5 yr of age. Postoperative BMI SDS (yr 1-6) had a weak positive correlation with BMI SDS at the time of diagnosis. In linear regression analysis, hypothalamic tumor involvement (P < 0.001), ponderal index at birth (P = 0.014), and BMI SDS at age 6-7 months (P = 0.029) and at age 5 yr (P < 0.001) had relevant and independent impacts on the development of obesity. Patients with hypothalamic involvement (n = 48) presented lower ponderal index and BMI SDS at birth and higher BMI SDS at the time of diagnosis (P < 0.001) as well as during annual follow-up (P < 0.001) compared with patients without hypothalamic involvement (n = 42). From childhood (3.5-4 yr) to the time of diagnosis, growth rates were reduced for patients with hypothalamic tumor involvement. Patients without hypothalamic involvement presented reduced growth rates in early infancy (age 10-12 months) that persisted until diagnosis. We conclude that reduced growth rates occur quite early in history; BMI SDS increases occur later and are predictive of obesity. Hypothalamic involvement is the major risk factor for obesity in patients with childhood craniopharyngioma.

Analysis of HIC-1 methylation and transcription in human ependymomas.

Ependymomas are among the most common brain tumors in children. They develop from ependymal cells lining the ventricular system of the CNS. Previous studies have demonstrated a significant rate of allelic loss at chromosome 17p13.3. The HIC-1 putative tumor-suppressor gene, which exhibits hypermethylation and loss of expression in various tumor entities including medulloblastomas and gliomas, maps to the affected region. In the present study, we analyzed HIC-1 in ependymomas. Therefore, we applied methylation-specific PCR of the 5'-untranslated region as well as of a central region of HIC-1 and bisulfite sequencing to determine the methylation status in 52 ependymomas of different histologic subtypes, grades and locations. In addition, we used a competitive RT-PCR approach for sensitive assessment of HIC-1 transcripts. Hypermethylation of at least one of the 2 analyzed regions was found in 43/52 (83%) cases. There was a significant correlation between hypermethylation of HIC-1 and nonspinal localization (p = 0.019) as well as age. Of 27 ependymomas, 22 (81%) showed absent or low expression of HIC-1. The elevated methylation of HIC-1 in nonspinal ependymomas supports the hypothesis that spinal and nonspinal ependymomas represent genetically distinct entities.

Human ependymomas reveal frequent deletions on chromosomes 6 and 9.

Ependymomas are glial tumors of the brain and spinal cord. Genetic aberrations associated with the development of these tumors have not been fully identified yet. In previous cytogenetic and comparative genomic hybridization studies, multiple genomic imbalances in ependymomas were found, including partial or whole chromosome losses (1p, 4q, 6q, 9, 10, 11, 13, 16, 17, 19q, 20q and 22q). The aim of this study was to map particularly the commonly affected regions in ependymomas. Thirty-three pairs of matched normal and tumor specimens from ependymoma patients were genotyped using 34 polymorphic microsatellite markers distributed over 15 chromosomes. Loss of heterozygosity (LOH) was found in 26 of 33 tumors (78.8%). The most frequent LOHs were found on the long arms of chromosomes 6 (30.3%) and 9 (27.3%). LOH was also detected on 3p14 (13.3%), 10q23 (10.3%) and 11q (18.2%). Because of the high percentage of LOH on chromosome 6 and 9, we conclude that important tumor suppressor genes are situated on these two chromosomes.