Microvessel density predicts behavior in pediatric optic pathway/hypothalamic gliomas

1556 Background: Optic pathway/hypothalamic gliomas (OPHG) are predominately low-grade tumors. However, OPHGs show an unpredictable behavior and there is no recognized histologic or molecular marker anticipating this behavior. This study was performed to investigate angiogenic features as possible independent prognostic factors. Methods: We searched the databases of the Hospital for Sick Children for patients with pathologically diagnosed OPHGs between 1985 and 2002. Tumor specimens were reviewed and reconfirmed as low-grade gliomas. Those with sufficient tissue for staining were included in the study. Sections were immunostained with factor VIII (F8) and counted for microvessel density (MD). A ratio of alpha-smooth muscle actin to F8 immunostaining was calculated to give a vascular maturity index. Vascular endothelial growth factor (VEGF) and VEGF-receptor immunostaining was performed to assess angiogenic features and MIB-1 labeling index (LI) to assess proliferation. These factors were evaluated with re...