gms | German Medical Science

ESBS 2005: Skull Base Surgery: An Interdisciplinary Challenge
7th Congress of the European Skull Base Society held in association with
the 13th Congress of the German Society of Skull Base Surgery

18. - 21.05.2005, Fulda, Germany

Expression of growth factors in unilateral vestibular schwannoma

Meeting Contribution

  • T. St÷ver - Dept. of Otorhinolaryngology, Hannover Medical University, Hannover, Germany
  • M. Diensthuber - Dept. of Otorhinolaryngology, Hannover Medical University, Hannover, Germany
  • T. Averbeck - Dept. of Otorhinolaryngology, Hannover Medical University, Hannover, Germany
  • T. Lenarz - Dept. of Otorhinolaryngology, Hannover Medical University, Hannover, Germany

ESBS 2005: Skull Base Surgery: An Interdisciplinary Challenge. 7th Congress of the European Skull Base Society held in association with the 13th Congress of the German Society of Skull Base Surgery. Fulda, 18.-21.05.2005. DŘsseldorf: German Medical Science GMS Publishing House; 2009. Doc05esbs71

doi: 10.3205/05esbs71, urn:nbn:de:0183-05esbs715

Published: January 27, 2009

© 2009 St÷ver et al.
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Outline

Text

Introduction: The vestibular schwannoma (VS) is a benign, slow-growing neoplasm that originates from the VIIIth cranial nerve sheath with an annual incidence of 13 per million. The pathogenesis of both sporadic VS and those associated with neurofibromatosis type II appears to be associated with an aberration of a tumor suppressor gene on chromosome 22q12. The biological background for the diverse growth patterns of VS is, however, largely unknown. This differing clinical and biological behaviour of VS may be explained by the presence of growth factors. Tumor expression of different growth factors indicating Schwann cell proliferation and tumor growth have recently been addressed in studies of vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), nerve growth factor (NGF), neuregulin-1 (NRG), epidermal growth factor (EGF), and erythropoitin (EPO). The present immunohistochemical study was conducted to determine whether transforming growth factor (TGF)-▀1 and glial cell line-derived neurotrophic factor (GDNF) as well as their receptors T▀R II, GFRα-1, and Ret are expressed in VS tissue. We also investigated whether the expression of these factors and their receptors is correlated with the Ki-67 labeling index, clinical growth rate, and demographic patient data.

Material and method: Immunohistochemical analysis for TGF-▀1 and GDNF and their receptors T▀R II, GFRα-1 and Ret was performed on formalin-fixed, paraffin-embedded archival surgical specimens. The Ki-67 labeling index (mean Ki-67 labeling index and highest Ki-67 labeling index for Antoni type A and B regions) and the clinical growth rate of VS were determined and correlated with the expression patterns of the examined neurotrophic factors and their receptors

Results: Results demonstrate co-expression of TGF-▀1 and GDNF with higher levels in Antoni type A than in Antoni type B regions. 95% of VS exhibited TGF-▀1-immunoreactivity and GDNF expression was found in 100% of VS specimens. 50% of VS displayed T▀R II-immunostaining, 100% showed positive reactions for GFRα-1 and 86% for Ret. Statistical analysis revealed no significant correlation in neurotrophin expression related to sex, age, tumor size, clinical growth rate or Ki-67-labeling indices.

Conclusions: Although our results do not show a significant correlation between neurotrophin expression and tumor size, clinical growth rate, Ki-67-labeling indices or demographic data the demonstrated expression of TGF-▀1 and GDNF may still suggest a biological role for both growth factors in VS. Trophic TGF-▀/GDNF synergism seems possible and is underscored by coexpression of both neurotrophic factors and their receptors. Ultimately, functional testing of TGF-▀1 and GDNF in a future study will be useful in exploring the proposed TGF-▀/GDNF synergism in VS.