Adolescent ; Adult ; Aged ; Cerebellar Neoplasms ; genetics ; Child ; Child, Preschool ; Chromosomes, Human, Pair 16 ; Female ; Humans ; Loss of Heterozygosity ; Male ; Medulloblastoma ; genetics ; Middle Aged

OBJECTIVETo investigate the epigenetic involvement of RASSF1A in intracranial primitive neuroectodermal tumors (PNETs) and compare the methylation patterns between medulloblastoma (MBs) and supratentorial PNETs (SPNETs).

METHODSThe methylation status at the promoter regions of RASSF1A was examined by methylation-specific polymerase chain reaction (MSP) in a cohort of 25 primary MBs, 9 primary SPNETs, 3 MB and 2 SPNET cell lines. RASSF1A-deficient PNET cell lines were treated with 5-aza-2'deoxycytidine, a demethylating agent, to explore the relationship between hypermethylation and the gene expression.

RESULTSThe results revealed no promoter hypermethylation of RASSF1A in 2 normal cerebellar and 5 normal cerebral tissue specimens examined. In contrast, promoter hypermethylation of RASSF1A was detected in 100% (25/25) of primary MBs, 6/9 of primary SPNETs, and all PNET cell lines. These results demonstrated that such epigenetic alteration was tumor-specific. The frequency of hypermethylation of RASSF1A in SPNETs was also found to be significantly lower than that in MBs (Fisher's exact test, P = 0.014). Treatment of RASSF1A-deficient PNET cell lines with 5-aza-2'deoxycytidine restored RASSF1A expression, providing evidence that promoter hypermethylation contributes to transcriptional silencing.

CONCLUSIONSThese results demonstrate that RASSF1A plays an important role in the development of intracranial PNETs. Different hypermethylation status of RASSF1A are found in PNET subtypes suggesting that MBs and SPNETs are epigenetical distinct tumors.

Adolescent ; Adult ; Aged ; Brain Neoplasms ; genetics ; pathology ; Cell Line, Tumor ; Cerebellar Neoplasms ; genetics ; pathology ; Child ; Child, Preschool ; DNA Methylation ; Female ; Gene Expression Regulation, Neoplastic ; Gene Silencing ; HeLa Cells ; Humans ; Infant ; Male ; Medulloblastoma ; genetics ; pathology ; Neuroectodermal Tumors, Primitive ; genetics ; pathology ; Promoter Regions, Genetic ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Tumor Suppressor Proteins ; genetics ; Young Adult

OBJECTIVETo study the genetic alterations of ganglioglioma through the entire genome, and to investigate the pathogenesis of this neoplasm.

METHODSComparative genomic hybridization was used to provide an overview of genetic abnormalities in gangliogliomas.

RESULTSFive cases of gangliogliomas, including 3 males and 2 females, were studied genetically. Loss of genetic materials on the short arm of chromosome 9(9p) was a common genetic alteration found in 3 of 5 cases. Overrepresentation of chromosome 7 was another recurrent chromosomal imbalance, which was further confirmed by fluorescence in situ hybridization. Immunohistochemical analysis was performed on epidermal growth factor receptor (EGFR), which was located on 7p11-p13. All five cases revealed no abnormal expression of EGFR. On the other hand, genetic imbalances were also involved in multiple chromosomes including 2q33-q34, 8q12-q22, 14q21-qter, 15q26-qter and Y.

CONCLUSIONLoss of genetic materials on chromosome 9p and gain on chromosome 7 may be associated with the pathogenesis of this neoplasm.

Adolescent ; Adult ; Brain Neoplasms ; genetics ; metabolism ; Chromosome Aberrations ; Chromosome Deletion ; Chromosomes, Human, Pair 7 ; Chromosomes, Human, Pair 9 ; Female ; Follow-Up Studies ; Ganglioglioma ; genetics ; metabolism ; Humans ; In Situ Hybridization, Fluorescence ; Male ; Nucleic Acid Hybridization ; Receptor, Epidermal Growth Factor ; metabolism

OBJECTIVETo evaluate whether deletion of chromosome 14q is involved in the carcinogenesis of primary glioblastoma multiforme and to identify possibly common deletion regions. METHJODS: Fourteen fluorescent dye-labeled polymorphic markers were used and polymerase chain reaction-based microsatellite analysis was employed to investigate loss of heterozygosity (LOH) on chromosome 14q in 20 primary glioblastoma multiforme (GBM).

RESULTSTen of twenty (50%) GBM displayed LOH at one or more of the markers on chromosome 14q. Five tumors showed either LOH or non-informative on all markers tested. The most frequent LOH was observed at locus D14S65 (57.1%) on 14q32.1, and in the chromosomal region spanning from D14S63 (47.1%) to D14S74 (46.7%) on 14q23-31. None of the informative loci exhibited microsatellite instability.

CONCLUSIONSAllelic deletion on chromosome 14q plays an important role in the pathogenesis of GBM. Chromosomal regions at locus D14S65 on 14q32.1 and spanning from D14S63 to D14S74 on 14q23-31 may harbor multiple tumor suppressor genes associated with GBM.

Adult ; Aged ; Chromosomes, Human, Pair 14 ; Female ; Genes, Tumor Suppressor ; Glioblastoma ; genetics ; Humans ; Loss of Heterozygosity ; Male ; Microsatellite Repeats ; Middle Aged

OBJECTIVETo reveal the molecular genetic mechanisms for the pathogenesis of glioblastoma (GBM) and determine which chromosomes or chromosomal regions may play a role in the pathogenesis of GBM or may harbor tumor suppressor genes (TSGs) associated GBM.

METHODSAn allelotype study of 21 cases of GBM was performed by polymerase chain reaction and loss of heterozygosity (LOH) analysis. Three hundred and eighty-two microsatellite markers covering all 22 autosomes were used. The mean genetic distance between two flanking markers is about 10 cM. Fluorescent dye-labeled primers and Perkin Elmer 377 DNA Sequencer were applied.

RESULTSLOH was observed on all chromosomal arms examined in this study. The LOH frequencies of 10q, 10p, 13q, 17p and 9p were the highest (>50%), on which high LOH frequencies were detected at the regions resided by the known TSGs including PTEN, DMBT1, p16, p15, p53 and Rb. The following commonly deleted regions were detected: 9p22-23, 10p12.2-14, 10q21.3, 13q12.1-14.1, 13q14.3-31, 17p11.2-12, 17p13, 3q24-27, 11p12-13, 14q31-32.3, 14q21-24.1, 22q13.2-13.3, 4q35, 4q31.1-31.2, 6qtel, 6q16.3.

CONCLUSIONThis study demonstrated that the pathogenesis of GBM is very complicated and associated with various molecular genetic abnormalities on lots of chromosomes. The chromosomal arms most closely relevant to the pathogenesis of GBM are 10q, 10p, 9p, 17p and 13q. Besides the well-known TSGs, such as PTEN, DMBT1, p16, p15, p53 and Rb, multiple unknown TSGs associated with GBM may be present on the commonly deleted regions observed for the first time in this study.

Adult ; Aged ; Chromosomes, Human ; genetics ; DNA, Neoplasm ; genetics ; Female ; Glioblastoma ; genetics ; Humans ; Loss of Heterozygosity ; Male ; Microsatellite Repeats ; Middle Aged

OBJECTIVETo study the mechanism of antisense epidermal growth factor receptor cDNA in growth suppression of glioblastomas cells.

METHODSGlioblastoma U87MG cells, which over-express epidermal growth factor receptor (EGFR), were transfected with antisense-EGFR constructs. Several clones with stable expression of lower or undetectable levels of EGFR protein were obtained. The effect of antisense-EGFR on cell differentiation was studied using morphological evaluation and western blotting analysis of glial fibrillary acidic protein (GFAP) expression. The effect of antisense-EGFR on cell cycle was studied by flow cytometry and immunohistochemical analysis of p53, Rb, p16 and CDK4 expressions. The effect of antisense-EGFR on telomerase activity was studied by telomeric repeat amplification protocol (TRAP) assay.

RESULTSU87MG cells that were transfected with antisense-EGFR constructs had smaller cell bodies and longer processes, and expressed higher level of GFAP compared with that of the control cells. Flow cytometric analysis showed that the proportion of cells in G(0)/G(1) phases of the cell cycle in the antisense EGFR cDNA transfected clones increased significantly when compared with control cells, whereas the proportion of cells in S phase decreased markedly. In addition, immunohistochemical analysis showed that the expression of wild-type p53 was significantly increased in the antisense-EGFR cDNA transfected clones, whereas the expressions of Rb, p16 and CDK4 were not altered. TRAP assay revealed that telomerase activity in the antisense-EGFR clones was significantly decreased.

CONCLUSIONSAntisense-EGFR transfection inhibits U87MG cell growth by inducing cell differentiation and p53 expression, G(1) cell cycle arrest and inhibition of telomerase activity.

Cell Line, Tumor ; DNA, Antisense ; therapeutic use ; DNA, Complementary ; therapeutic use ; Flow Cytometry ; Glioblastoma ; chemistry ; drug therapy ; pathology ; Humans ; Immunohistochemistry ; Receptor, Epidermal Growth Factor ; antagonists & inhibitors ; genetics ; Retinoblastoma Protein ; analysis ; Transfection ; Tumor Suppressor Protein p53 ; analysis

OBJECTIVETo investigate global genetic alterations in medulloblastoma, and to localize critical chromosomal loci with allelic imbalances associated with the development of medulloblastoma.

METHODSA high-resolution genome-wide allelotype analysis, including 384 microsatellite markers, was performed in 12 medulloblastomas.

RESULTSAn average of 238 (62.3%) allelic imbalances were detected on all 39 autosomal arms. Non-random allelic gains or losses were detected on chromosomes 7q (58.3%), 8p (66.7%), 16q (58.3%), 17p (58.3%) and 17q (66.7%). In addition, chromosomal arms with frequencies of allelic imbalances higher than the mean percentage were identified on 3p (33.3%), 3q (33.3%), 4q (41.7%), 7p (33.3%), 8q (41.7%), 10q (41.7%), 13q (33.3%), 14q (33.3%) and 20q (33.3%). No relationship was found between the frequency of allelic imbalances and the clinical outcome of the patients.

CONCLUSIONSA global view of the genetic alterations in medulloblastoma was provided. The allelic imbalances involving chromosomes 7q, 8p, 16q, 17p and 17q may play an important role in the pathogenesis of medulloblastoma.

Adolescent ; Adult ; Alleles ; Allelic Imbalance ; Cerebellar Neoplasms ; genetics ; Child ; Child, Preschool ; Chromosomes, Human, Pair 16 ; Chromosomes, Human, Pair 17 ; Chromosomes, Human, Pair 7 ; Chromosomes, Human, Pair 8 ; Female ; Genotype ; Humans ; Male ; Medulloblastoma ; genetics ; Microsatellite Repeats ; genetics

To identify the expression of thrombopoietin (TPO) receptors (c-mpl) on central nervous system (CNS) and to evaluate the role of TPO on neural cell proliferation and protection, immunohistochemical staining, RT-PCR, MTT, and annexin-V methods were used in this study. The results showed the expression of TPO receptor on human CNS and murine neural cells. C-mpl mRNA was identified in human cerebral hemispheres and cerebellum, and mouse neural cell line C17.2 by RT-PCR. C-mpl was also confirmed in human cerebral hemispheres by immunohistostaining with con-focal microscopy. Furthermore, TPO had a stimulating effect on the growth of in vitro neural cell C17.2 by MTT assay. The anti-apoptotic effect of TPO on C17.2 cells was also demonstrated by staining with annexin-V and PI. In conclusion, the first evidence showed the expression of TPO receptor c-mpl in central nervous system. Moreover, the effect of TPO on neural cell proliferation and anti-apoptosis was also demonstrated on in vitro neural cells.
Animals ; Apoptosis ; drug effects ; Brain Chemistry ; Cell Line ; Cell Proliferation ; drug effects ; Erythropoietin ; pharmacology ; Humans ; Mice ; Neoplasm Proteins ; analysis ; Neurons ; drug effects ; Oncogene Proteins ; analysis ; Proto-Oncogene Proteins ; analysis ; Receptors, Cytokine ; analysis ; Receptors, Thrombopoietin ; Thrombopoietin ; pharmacology

Adult ; Brain Neoplasms ; genetics ; DNA, Neoplasm ; analysis ; Female ; Genome ; Glioblastoma ; genetics ; Humans ; Loss of Heterozygosity ; Microsatellite Repeats ; Neoplasm Recurrence, Local ; genetics ; Polymerase Chain Reaction

OBJECTIVETo investigate molecular genetic alterations associated with primary and corresponding recurrent glioblastoma multiforme(GBM) and to identify which chromosomal regions of the whole genome may be involved in the recurrence of primary GBM.

METHODSA high-resolution allelotyping study of one patient's primary GBM and corresponding recurrent GBM was performed by PCR-based loss of heterozygosity(LOH) analysis with the use of 382 fluorescent dye-labeled polymorphic microsatellite markers covering all 22 autosomes. The mean genetic distance between two flanking markers is 10 cM.

RESULTSLOH at locus D9S157 on 9p21 and at loci D10S537, D10S185, D10S192, D10S597, D10S587, D10S217 on 10q21.3-26.3 was observed in the primary GBM. As for corresponding recurrent tumor, LOH was observed not only in expanded regions on 9p21 and 10q21.3-26.3 but also on multiple other chromosomal arms, including 1q, 7p,7q, 21q, 20p, 20q, 10p, 19p, 19q.

CONCLUSIONChromosome 9p and 10q may be involved in the development of this GBM. Although histopathological diagnoses of the primary and corresponding recurrent tumor are identical, the recurrence of GBM is characterized by an increased involvement of molecular genetic abnormalities and may be accompanied by inactivation of more tumor suppressor genes.

Adult ; Alleles ; Chromosome Mapping ; methods ; Chromosomes, Human, Pair 1 ; genetics ; Chromosomes, Human, Pair 10 ; genetics ; Chromosomes, Human, Pair 19 ; genetics ; Chromosomes, Human, Pair 20 ; genetics ; Chromosomes, Human, Pair 21 ; genetics ; Chromosomes, Human, Pair 7 ; genetics ; Chromosomes, Human, Pair 9 ; genetics ; DNA ; genetics ; Female ; Glioblastoma ; genetics ; pathology ; surgery ; Humans ; Loss of Heterozygosity ; Microsatellite Repeats ; Neoplasm Recurrence, Local