Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017636 (glioblastoma)
 18,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aberrations of genes/proteins regulating cell cycle and growth, increased proliferation and telomerase activity (TA) are documentable in glioblastoma multiforme. TA is more frequently detectable in secondary glioblastoma, which is also characterized by p53 mutation/overexpression. Discordant telomere (Te) length values have been reported in glioblastomas with and without TA. In 31 glioblastomas, in which pre-existing astrocytoma was not documented, we compared cases with and without TA for the expression of p53, EGFR, c-Myc, MIB-1 and Topoisomerase IIalpha; p53 mutations were also investigated by SSCP-PCR. Correlations were made with Te parameters [TePs: number (TeNo), length and area] as evaluated by image analysis in interphase nuclei of fluorescence in situ hybridization (FISH)-processed sections. We found no differences in the expression of the proteins evaluated and in TePs, except Te/nuclear area %, which was significantly lower in TA+ cases (p=0.02). TePs were, instead, inversely correlated with TA (p=0.0001). TA was positively correlated with MIB1 staining index in the TA+ cases (p=0.033), which also showed a positive correlation between TeNo and EGFR expression (p=0.042), and a trend towards a negative correlation between TeNo and p53 expression (p=0.05). Tumors overexpressing EGFR had a significantly shorter lifetime (p=0.0001). TeNo seems to be inversely correlated to tumor proliferation and lifetime in glioblastoma multiforme.
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PMID:In situ detection of telomeres by fluorescence in situ hybridization and telomerase activity in glioblastoma multiforme: correlation with p53 status, EGFR, c-myc, MIB1, and Topoisomerase IIalpha protein expression. 1461 23

Glioblastoma (GB) often has loss of heterozygosity on the chromosomes, 1p, 10p, 10q, 11p, 17p, 19q, 22q, and several others. In the case of chromosome 12q, however, it remains to be seen whether LOH occurs. Apaf-1, the apoptotic protease activating factor-1, located at chromosome 12q22-23, is a major effecter of the p53 mediated apoptosis pathway, and Apaf-1 inactivation due to chromosome 12q22-23 LOH and hypermethylation may be involved in some of the neoplasms in malignancy. However, little is known about the frequency of the 12q22-23 LOH or the state of Apaf-1 in GB. To elucidate their involvement in GB, we analyzed a series of 33 GBs for chromosome 12q22-23 LOH, Apaf-1 mRNA expression, and Apaf-1 protein expression, using microsatellite analysis, reverse transcription (RT)-PCR analysis, and immunohistochemical (IHC) analysis, respectively. We also evaluated if and how the 12q22-23 LOH correlated with the p53 gene mutation and EGFR gene amplification. Chromosome 12q22-23 LOH was detected in 14 (42%) of 33 cases. Among the examined cases with LOH at 12q22-23, a low expression of Apaf-1 mRNA was detected in 9 (69%) of 13 cases, and a low expression of Apaf-1 protein was detected in 12 (86%) of 14 cases. The 12q22-23 LOH was significantly correlated with low expression of mRNA and protein (p<0.05, p<0.001 respectively). The p53 gene mutation and EGFR gene amplification were found in 13 cases (39%) and 8 cases (24%), respectively, and these gene alterations were inversely correlated. However, 12q22-23 LOH had no correlations with the p53 gene mutation or EGFR gene amplification. Six of 9 GBs (67%) with neither p53 gene mutation nor EGFR gene amplification tested positive for 12q22-23 LOH. These GBs are likely to belong to another subset independent from the 2 common genetic subsets in GB (one with p53 gene mutation and without EGFR gene amplification, and the other with EGFR gene amplification and without p53 gene mutation). Twenty-three (70%) out of the 33 GBs with the 12q22-23 LOH also tested positive for Apaf-1 inactivation or p53 gene mutation. This high frequency of alterations in the apoptosis-associated factors prompts a speculation that abrogation of the Apaf-1 and p53 mediated apoptosis pathway may play an important role in the tumorigenesis of GB.
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PMID:Frequent LOH at chromosome 12q22-23 and Apaf-1 inactivation in glioblastoma. 1519 36

Glioblastomas frequently carry mutations in the PTEN tumor suppressor gene on 10q23.3. The tumor suppressor properties of Pten are closely related to its inhibitory effect on the phosphatidyl-inositol-3'-kinase (Pi3k)-dependent activation of protein kinase B (Akt) signalling. Here, we report on the analysis of 17 genes related to the Pi3k/Akt signalling pathway for genetic alteration and aberrant expression in a series of 103 glioblastomas. Mutation, homozygous deletion or loss of expression of PTEN was detected in 32% of the tumors. In contrast, we did not find any aberrations in the inositol polyphosphate phosphatase like-1 gene (INPPL1), whose gene product may also counteract Pi3k-dependent Akt activation. Analysis of genes encoding proteins that may activate the pathway upstream of Pi3k revealed variable fractions of tumors with EGFR amplification (31%), PDGFRA amplification (8%), and IRS2 amplification (2%). The protein tyrosine kinase 2 (PTK2/FAK1) gene was neither amplified nor overexpressed at the mRNA level. Investigation of three genes encoding catalytic subunits of Pi3k (PIK3CA, PIK3CD, and PIK3C2B) revealed amplification of PIK3C2B (1q32) in 6 tumors (6%). Overexpression of PIK3C2B mRNA was detected in 4 of these cases. PIK3CD (1p36.2) and PIK3CA (3q26.3) were not amplified but PIK3CD mRNA was overexpressed in 6 tumors (6%). Amplification and overexpression of AKT1 was detected in a single case of gliosarcoma. The IRS1, PIK3R1, PIK3R2, AKT2, AKT3, FRAP1, and RPS6KB1 genes were neither amplified nor overexpressed in any of the tumors. Taken together, our data indicate that different genes related to the Pi3k/Akt signalling pathway may be aberrant in glioblastomas.
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PMID:Genetic alterations and aberrant expression of genes related to the phosphatidyl-inositol-3'-kinase/protein kinase B (Akt) signal transduction pathway in glioblastomas. 1465 56

Two metachronous glioblastomas with different cerebral locations in a 53-year-old long-term survival patient were analyzed by multiple genetic approaches. Using comparative genomic hybridization a different pattern of chromosomal aberrations was observed, with 19 imbalances in the first tumor and only 2 imbalances in the second. Sequence analysis revealed a distinct mutation profile in each tumor, with amino acid substitutions in the p53 and PTEN genes only in the first tumor, ie, p53 in codon 273 (CGT-->TGT, Arg-->Cys) and PTEN in codon 336 (TAC-->TTC, Tyr-->Phe). A splicing acceptor site PTEN mutation (IVS8-2A>G) was observed only in the second GBM. EGFR amplification, mutations of p16INK4a/CDKN2A or p14ARF were not observed. According to the results of p53 mutational analysis and EGFR amplification studies, the first tumor is classified as a type 1 GBM, whereas the alterations in the second one are different from those typically encountered in type 1 or type 2 tumors. In conclusion, our data strongly suggest that the metachronous tumors in this patient are exceptional in that they developed independently from each other. Whether the molecular features of the first glioblastoma are associated with the notably extended recurrence-free period of 5 years remains to be elucidated.
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PMID:Independent molecular development of metachronous glioblastomas with extended intervening recurrence-free interval. 1465 63

Glioblastoma is a rapidly growing tumor that accounts for more than 50% of all primary gliomas. Amplification of oncogenes and deletion of tumor suppressor genes frequently affects tumor progression. Thus, the goal of this study was to conduct a comprehensive analysis of gene aberrations of individual glioblastomas. A genome DNA microarray (GenoSensor Array 300), spotted with 287 target genes, was used to analyze resected tissue from 11 different high-grade gliomas. The average number of gene aberrations was 9.0 per case (WHO grade III) and 13.3 per case (WHO grade IV). EGFR was the most frequent amplified gene in this series (4 of 11 cases), and high-level amplification was also detected for EGFR, SAS/CDK4, and AKT1. A high frequency of deleted genes was observed in 6 of 11 cases (54.5%), including FGFR2, MTAP, and DMBT1. The detected gene aberrations were matched to the classical primary glioblastoma pathway in five of nine cases. We conclude that the GenoSensor Array 300 genomic DNA microarray is a useful method for the comprehensive identification of amplified and deleted genes in glioblastoma.
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PMID:Detection of gene amplification and deletion in high-grade gliomas using a genome DNA microarray (GenoSensor Array 300). 1475 42

In order to identify response predictors for a post-operative glioblastoma therapy consisting of tamoxifen, carboplatin and radiotherapy, expression of 12 antigens was evaluated in 36 newly diagnosed tumours and 13 recurrences. Results were correlated with the clinical course of the disease. Antigen expression was assessed immunohistochemically for CD44s, TGF-beta2, TGF-alpha, progesterone receptor, estrogen receptor, EGFR, urokinase, urokinase inhibitor 1, CD87, p53 protein and Ki-67. Vessel density was determined by labelling of endothelia with von Willebrand factor. Response to chemotherapy correlated positively with cell density (p < 0.05) and negatively with CD44 over-expression (p < 0.02). Further, a positive correlation between age and CD44 expression (p < 0.05) and a negative correlation between age and p53 accumulation (p < 0.01) was found. In tumour recurrences expression of CD44 was significantly higher in local recurrences than in distant multifocal recurrences (p < 0.02), suggesting that CD44 may predominantly be associated with cell adhesion in glioblastomas.
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PMID:CD44 expression and tumour cell density correlate with response to tamoxifen/carboplatin chemotherapy in glioblastomas. 1501 79

With tendency to invade rapidly in the brain, malignant gliomas are very resistant to conventional therapies including radiation and chemotherapy. Recent advances in genetic and molecular techniques have made it possible to define characteristic molecular profiles of malignant gliomas. Based on the list of the molecules closely related to glioblastoma tissues, we reviewed strategies targeting them. Target molecules extensively studied include EGFR, PTEN, telomerase and signal pathway modulators for Ras/Raf/MAPK and PI3K/Akt/mTOR pathways. Therapies targeting specific molecules may result in killing tumor cells effectively while keeping normal cells intact.
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PMID:Molecular targeting for malignant gliomas (Review). 1506 31

It was recently reported that the human CD109 gene encodes a glycosyl-phosphatidylinositol-anchored glycoprotein that is a member of the alpha(2)-macroglobulin/C3, C4, C5 family of thioester-containing proteins. In this study, we found that the expression of mouse CD109 gene was upregulated in NIH3T3 cells expressing RET tyrosine kinase with a multiple endocrine neoplasia 2B mutation. Northern blot analysis showed a high level of expression of the CD109 gene only in the testis in normal human and mouse tissues. In addition, its expression was high in some human tumor cell lines, which included squamous cell carcinoma and glioblastoma cell lines, whereas it was undetectable in neuroblastoma and small-cell lung carcinoma cell lines. When CD109 expression was examined in 33 cases of human lung cell carcinomas by quantitative RT-PCR, a significant high expression of CD109 was detected in about half of squamous cell carcinomas examined, but not in adenocarcinoma, large-cell carcinoma and small-cell carcinoma. Similarly, upregulation of CD109 was observed in nine out of 17 esophageal squamous cell carcinomas. Thus, these results suggested that CD109 might be a useful molecular target for the development of new therapeutics for malignant tumors, such as squamous cell carcinoma.
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PMID:Expression of CD109 in human cancer. 1511 2

EGFR amplification is a frequent genetic alteration in primary (de novo) glioblastomas, and is often associated with structural alterations. Most common is variant III (EGFRvIII), which results from a non-random 801 bp in-frame deletion of exons 2 to 7 of the EGFR gene. We assessed amplification and overexpression of EGFRvIII and wild-type EGFR in 30 glioblastoma biopsies. Immunohistochemically, EGFR overexpression was observed in 20 (67%) of 30 glioblastomas. Eight (27%) cases also showed immunoreactivity to an EGFRvIII antibody. In 6 of these cases, the pattern of EGFR and EGFRvIII overexpression was compared in serial sections: In 4 cases, areas with immunoreactivity to EGFRvIII largely coincided with wild-type EGFR expression. In the other 2 cases, the areas immunoreactive to EGFRvIII were significantly less extensive than EGFR-positive areas. To assess whether EGFRvIII is predominantly amplified in tumors with concurrent wild-type EGFR amplification, we carried our real-time quantitative PCR using 2 sets of primers located in exon 2 and intron 15 of the EGFR gene. A > 5-fold ratio of relative copy numbers between intron 15 (present both in wild-type EGFR and EGFRvIII) and exon 2 (present only in wild-type EGFR, but missing in EGFRvIII) suggested predominant amplification of EGFRvIII in only 3 (10%) of 30 glioblastomas. The observation that intratumoral wild-type EGFR overexpression is often more extensive and that predominant amplification of EGFRvIII is a rare event would limit the effectiveness of therapeutic approaches based on selective targeting of EGFRvIII.
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PMID:Predominant expression of mutant EGFR (EGFRvIII) is rare in primary glioblastomas. 1519 25

Nearly all brain tumors develop following the progressive accumulation of genetic alterations of oncogenes and tumor suppressor genes (such as p53 and retinoblastoma protein). Furthermore, aberrations in the nuclear matrix often contribute to genomic instabilities and the development of cancer. We have previously shown that nuclear-restricted protein/brain (NRP/B), a member of the BTB/Kelch repeat family, is a nuclear matrix protein normally expressed in neurons but not in astrocytes, and that it is an early and specific marker of neurons during the development of the central nervous system. Here, we show aberrant expression of NRP/B in human brain tissues. NRP/B is expressed in the cytoplasm of human brain tumor cells (glioblastoma, GBM) arising from astrocytes. NRP/B mutations (13 mutations in the Kelch domains, two in the intervening sequence (IVS) domain and two in the BTB domain) were detected in brain tumor cell lines (A-172, CCF-STTG1, SK-N-SH and U87-MG) and in primary human malignant GBM tissues (eight samples). More importantly, we found that NRP/B mutants, but not wild-type (wt) NRP/B, increased the activation of ERK and consequently promoted cell proliferation, attenuated caspase activation and suppressed the cellular apoptosis induced by the stressful stimulus cisplatin (10 microM). These events were observed to occur via a p53-mediated pathway. In addition, while wt NRP/B was associated with actin, mutations in the Kelch domains of NRP/B led to its reduced binding affinity to actin. Thus, alterations and gene mutations within the NRP/B gene may contribute to brain tumorigenesis by promoting cell proliferation, suppressing apoptosis and by affecting nuclear cytoskeleton dynamics.
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PMID:Genetic alterations of the NRP/B gene are associated with human brain tumors. 1520 78


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