Expression of Activated Epidermal Growth Factor Receptors, Ras-Guanosine Triphosphate, and Mitogen-activated Protein Kinase in Human Glioblastoma Multiforme Specimens

Expression of Activated Epidermal Growth Factor Receptors, Ras-Guanosine Triphosphate, and... AbstractOBJECTIVE:Amplification of the epidermal growth factor receptor (EGFR) is a common event in the molecular pathogenesis of high-grade astrocytic tumors, occurring in 50% of glioblastoma multiforme (GBM) cases. A subset of GBMs also express a constitutively phosphorylated truncated receptor (EGFRvlll). Expression of transfected EGFRvlll in cells has been reported to activate the Ras-mitogen-activated protein kinase pathway and to provide a growth advantage. Novel therapeutic agents targeting signal transduction pathways are entering early clinical trials; determination of which GBMs express EGFRvlll might help identify patients who might benefit from these biological agents.METHODS:A cohort of 15 flash-frozen surgical specimens (12 GBMs, 2 gliosarcomas, and 1 adult low-grade glioma) were evaluated for EGFR and EGFRvlll expression and for EGFR activation status using immunohistochemical (IHC) analysis, Western blotting, and reverse transcription-polymerase chain reaction assays. Levels of activated Ras-guanosine triphosphate were measured using a nonradioactive luciferase-based technique. Mitogen- activated protein kinase activation was determined using a myelin basic protein assay. IHC analysis was performed on paraffin-embedded, formalin-fixed, pathological specimens. Normal control samples included white matter specimens distal to tumors (n = 5), a sample obtained during a lobectomy for treatment of epilepsy (n = 1), and cultured fetal human astrocytes (n = 1).RESULTS:We demonstrated higher levels of activated Ras and mitogen-activated protein kinase in GBM specimens, compared with normal brain tissue or the low-grade glioma. There was a very good correlation between results obtained using specialized molecular techniques and those obtained using routine IHC techniques. Screening for EGFRvlll expression may be of prognostic importance, because patients with EGFRvlll-positive tumors exhibited shorter life expectancies (mean survival time for patients with EGFRvlll-positive tumors, 4.5 ± 0.6 mo; mean survival time for patients with EGFRvlll-negative tumors, 11.2 ± 0.9 mo).CONCLUSION:We demonstrated that routine IHC techniques using commercially available antibodies are capable of identifying which GBM specimens express EGFRvlll and whether the EGFRs are activated. Such a molecular classification of GBMs might allow us to determine which patients might benefit from biologically targeted therapies. In addition, characterization of specimens with respect to their EGFRvlll status seems to be of prognostic value. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Neurosurgery Oxford University Press

Expression of Activated Epidermal Growth Factor Receptors, Ras-Guanosine Triphosphate, and Mitogen-activated Protein Kinase in Human Glioblastoma Multiforme Specimens

Expression of Activated Epidermal Growth Factor Receptors, Ras-Guanosine Triphosphate, and Mitogen-activated Protein Kinase in Human Glioblastoma Multiforme Specimens

Expression of Activated Epidermal Growth Factor Receptors, Ras-Guanosine Triphosphate, and Mitogen-activated Protein Kinase in Human Glioblastoma Multiforme Specimens Matthias M. Feldkamp, M.D., Prateek Lala, B.Sc., Nelson Lau, B.Sc., Luba Roncari, M.Sc., Abhijit Guha, M.D. Samuel Lunenfeld Research Institute (M M F, PL, NL, LR, A C ), M o u n t Sinai H osp ita l; D iv is io n o f N eurosurgery (M M F , A C ), T o ro n to W estern H osp ita l, U n ive rsity H ea lth N e tw o rk , and U n iv e rs ity o f T o ro n to ; and D e p a rtm e n t o f Surgical O n c o lo g y (AC), O n ta rio C ancer Institute/Princess M argaret H ospita l, T oronto, O n ta rio , Canada O B JEC T IV E: Am plification of the epidermal growth factor receptor (EG FR ) is a common event in the molecular pathogenesis of high-grade astrocytic tumors, occurring in 5 0 % of glioblastoma m ultiforme (G B M ) cases. A subset of G B M s also express a constitutively phosphorylated truncated receptor (E G F R v lll). Expression of transfected E G F R v lll in cells has been reported to activate the Ras-mitogen-activated protein kinase pathway and to provide a growth advantage. Novel therapeutic agents targeting signal transduction pathways are entering early clinical trials; determination of which G B M s express E G F R v lll might help identify patients who might benefit from these biological agents. M ET H O D S: A cohort of 15 flash-frozen surgical specimens (12 G BM s, 2 gliosarcomas, and 1 adult low-grade glioma) were evaluated for EG FR and E G F R v lll expression and for EG FR activation status using immunohistochemical (IH C ) analysis, W estern blotting, and reverse transcription-polymerase chain reaction assays. Levels of activated Ras-guanosine triphosphate were measured using a nonradioactive luciferase-based technique. Mitogen- activated protein kinase activation was determined using a myelin basic protein assay. IH C analysis was performed on paraffin-embedded, formalin-fixed,...
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Publisher
Oxford University Press
Copyright
© Published by Oxford University Press.
ISSN
0148-396X
eISSN
1524-4040
D.O.I.
10.1097/00006123-199912000-00034
Publisher site
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Abstract

AbstractOBJECTIVE:Amplification of the epidermal growth factor receptor (EGFR) is a common event in the molecular pathogenesis of high-grade astrocytic tumors, occurring in 50% of glioblastoma multiforme (GBM) cases. A subset of GBMs also express a constitutively phosphorylated truncated receptor (EGFRvlll). Expression of transfected EGFRvlll in cells has been reported to activate the Ras-mitogen-activated protein kinase pathway and to provide a growth advantage. Novel therapeutic agents targeting signal transduction pathways are entering early clinical trials; determination of which GBMs express EGFRvlll might help identify patients who might benefit from these biological agents.METHODS:A cohort of 15 flash-frozen surgical specimens (12 GBMs, 2 gliosarcomas, and 1 adult low-grade glioma) were evaluated for EGFR and EGFRvlll expression and for EGFR activation status using immunohistochemical (IHC) analysis, Western blotting, and reverse transcription-polymerase chain reaction assays. Levels of activated Ras-guanosine triphosphate were measured using a nonradioactive luciferase-based technique. Mitogen- activated protein kinase activation was determined using a myelin basic protein assay. IHC analysis was performed on paraffin-embedded, formalin-fixed, pathological specimens. Normal control samples included white matter specimens distal to tumors (n = 5), a sample obtained during a lobectomy for treatment of epilepsy (n = 1), and cultured fetal human astrocytes (n = 1).RESULTS:We demonstrated higher levels of activated Ras and mitogen-activated protein kinase in GBM specimens, compared with normal brain tissue or the low-grade glioma. There was a very good correlation between results obtained using specialized molecular techniques and those obtained using routine IHC techniques. Screening for EGFRvlll expression may be of prognostic importance, because patients with EGFRvlll-positive tumors exhibited shorter life expectancies (mean survival time for patients with EGFRvlll-positive tumors, 4.5 ± 0.6 mo; mean survival time for patients with EGFRvlll-negative tumors, 11.2 ± 0.9 mo).CONCLUSION:We demonstrated that routine IHC techniques using commercially available antibodies are capable of identifying which GBM specimens express EGFRvlll and whether the EGFRs are activated. Such a molecular classification of GBMs might allow us to determine which patients might benefit from biologically targeted therapies. In addition, characterization of specimens with respect to their EGFRvlll status seems to be of prognostic value.

Journal

NeurosurgeryOxford University Press

Published: Dec 1, 1999

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