Abstract A30: Investigation of imatinib mesylate effect on vestibular schwannoma tumor by using in vivo corneal angiogenesis model

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Abstract Objective: Vestibular schwannomas (VSs) are histologically benign, encapsulated, and slow growing tumors that arise from Schwann cells of the vestibular branch of eighth of twelve cranial nerves (Vestibulo-cochlear nerve) that is located next to porus acusticus internus. The tested hypothesis was that gleevec reduces angiogenic capacity in patients with VSs and NF-2 associated schwannomas by using corneal angiogenesis assay. This in vivo therapeutic efficacy might induce new clinical trials in the treatment of VSs and add a medical treatment option in the armamentarium. Methods: A total of 121 patients were treated by microsurgical VS resection at the School of Medicine, Neurosurgery Department and Institute of Neurological Sciences of Marmara University, Istanbul, Turkey between 1988–2009. Randomly selected 10 (6 sporadic VS, 4 NF-2 associated VS) samples were used. Angiogenic potential of VS and NF-2 associated VSs tumors in response to imatinib were compared with the healthy subjects by using immunohistochemistry, western blot and corneal angiogenesis assay. Results: Positive and negative control tissues showed significantly higher and lower angiogenic potential (p<0.05), compared with both sporadic and NF-2 associated VS tumor groups. Imatinib activity significantly reduced angiogenic potential, in both sporadic VS and NF-2 associated VS tumor groups. PDGF-A and PDGFR-alpha as well as PDGF-B and PDGFR-beta expression in sporadic VS and NF-2 associated VS were higher than the control groups (p<0.05). Conclusion: The results of the present study indicate that NF-2 associated VSs showed significantly higher angiogenic potential than sporadic VSs. Moreoever, both sporadic and NF-2 associated VSs had significantly higher angiogenic potential compared with normal brain tissue. We conclude that, in the treatment of VS and NF-2 tumors, imatinib is an alternative approach to surgical resection and radiosurgery. Citation Information: Cancer Prev Res 2011;4(10 Suppl):A30.