Immunolocalization of erythropoietin and erythropoietin receptor in vestibular schwannoma

Vestibular schwannomas constitute approximately 6% of intracranial tumors. Apart from the association with neurofibromatosis-2 (NF-2), where a defect in chromosome 22 has been identified, the pathogenesis of sporadic vestibul ar schwannomas is largely unknown. Very few studies have explored the role of neurotrophic growth factors in vestibular schwannoma. The objective of t his study is to evaluate for the presence and pattern of EPO and EPO-R expr ession within vestibular schwannomas. Our hypothesis that erythropoietin (E PO) and erythropoietin receptor (EPO-R) were expressed in vestibular schwan nomas was based on a recent report of rapid growth of a vestibular schwanno ma in a patient undergoing preoperative EPO treatment. Using immunohistoche mistry, we have demonstrated that both EPO and EPO-R are expressed in a maj ority of these tumors.