αvβ3 Integrin in central nervous system tumors

αvβ3 is an integrin specifically expressed in endothelial cells of newly forming blood vessels. Integrin-mediated angiogenesis is hypothesized to play a central role in the development and the progression of central nervous system neoplasms. Accordingly, it is considered a potential target for antiangiogenic therapy. In the current study, we compare the expression of αvβ3 in ependymomas, oligodendrogliomas, pilocytic astrocytomas, medulloblastomas, and vestibular schwannomas (acoustic neuromas). Samples of 5 tumors of each of the 5 tumor types were harvested surgically and frozen. After the pathological diagnosis was confirmed, immunohistochemistry was performed using an anti-αvβ3 monoclonal antibody (LM609). The expression of αvβ3 was assessed using a 4-tiered (0-3) grading scheme reflecting the percentage of positively staining vessels. All vestibular schwannomas demonstrated strong (grade 3) αvβ3 expression. The expression was uniformly prominent in Antoni B regions of the tumors. Of 5 ependymomas, 4 demonstrated uniformly strong αvβ3 expression. Oligodendrogliomas, medulloblastomas, and pilocytic astrocytomas demonstrated more variable αvβ3 expression. αvβ3 may contribute significantly to angiogenesis in vestibular schwannomas and ependymomas. Despite the high vascular density of oligodendrogliomas, pilocytic astrocytomas, and medulloblastomas, these tumors had variable moderate αvβ3 expression. This discrepancy suggests temporal and/or regional variability in the angiogenesis in these types of tumor. This study provides the first demonstration of αvβ3 expression in vestibular schwannomas, medulloblastomas, and pilocytic astrocytomas.