Artikel
Erythropoietin and Erythropoietin Receptor Expression in Vestibular Schwannoma
Expression des neurotrophen Faktors Erythropoetin und seines Rezeptors im Akustikusneurinom
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Veröffentlicht: | 7. September 2006 |
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Gliederung
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Background: Erythropoietin expression is regulated by the transcription factor hypoxia-inducible factor-1a [Ref. 1]. Erythropoietin signaling via erythropoietin receptor results in stimulation of cell proliferation and elevated expression of the antiapoptotic protein bcl-2 followed by inhibition of apoptosis. Erythropoietin has been shown to be associated with Schwann cell proliferation [Ref. 2] and a recent report suggested a role in vestibular schwannoma growth [Ref. 3].
Methods: Immunohistochemical examination of hypoxia-inducible factor-1a, erythropoietin, erythropoietin receptor and bcl-2 was performed on formalin-fixed, paraffin-embedded archival surgical specimens. Microvessel density and Ki-67-labeling index of vestibular schwannoma were determined and correlated with the immunoreactivity pattern of the examined factors.
Results: Immunoreactivity data demonstrate expression for hypoxia-inducible factor-1a, erythropoietin, erythropoietin receptor and bcl-2 in vestibular schwannoma. Sixty-six percent of the cases showed erythropoietin expression and erythropoietin receptor was found in 86% of tumor samples. A significantly positive correlation of the immunoreactivity scores of Epo/EpoR and bcl-2 expression could be noted. In case of tumor specimens with high levels of hypoxia-inducible factor-1a expression a significantly higher Ki-67-labeling index was observed.
Conclusion: Expression of erythropoietin and erythropoietin receptor might indicate a functional role in vestibular schwannoma biology. The observed correlation of Epo/EpoR and bcl-2 expression levels may suggest a proliferative and antiapototic role of the Epo/EpoR system in VS.
References
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- Acs G, Acs P, Beckwith SM, Pitts RL, et al. Erythropoietin and erythropoietin receptor expression in human cancer. Cancer Res 2001;61:3561-5.
- 2.
- Li X, Gonias SL, Campana WM. Schwann cells express erythropoietin receptor and represent a major target for Epo in peripheral nerve injury. Glia 2005;51:254-65.
- 3.
- Falcioni M, Taibah A, De Donato G, et al. Fast-growing vestibular schwannoma. Skull Base Surg 2000;10:95-9