High microvessel density in primitive neuroectodermal brain tumors of childhood

Microvessel density (MVD), a measure of tumor angiogenesis, has been shown to correlate significantly with overall and progression-free survival outco mes in various cancers including astrocytic brain tumors. To assess if the MVD is an independent prognostic factor in primitive neuroectodermal tumors (PNET) of the central nervous system, formalin-fixed paraffin-embedded tum or sections of 78 children with PNET were studied by CD34 immunohistochemis try to highlight endothelial cells. Microvessel density was determined in t he most active area of neovascularization according to well-established met hods. While it was shown that MVD showed considerable inter-tumor variabili ty (median 75; range 20-345 microvessels per 0.7 mm(2) field), no significa nt associations were found between MVD and metastasis or survival outcomes. We conclude that many PNETs are highly vascular CNS tumors, indicating pot ent angiogenic activity. Therefore, these tumors would be good candidates f or antiangiogenic strategies. However, MVD determined in the most active ar ea of neovascularization is not a predictor of metastatic potential or surv ival outcomes in childhood PNET.