Does Vasculogenic Mimicry Exist in Astrocytoma?

Vasculogenic mimicry (VM) has been observed in melanoma and in some nonmelanoma tumor types. It is unknown whether a similar VM phenomenon exists in astrocytoma. The present study was to examine 45 astrocytomas (including World Health Organization grade II 15 cases, grade III 15 cases, and grade IV 15 cases) by CD34 endothelial marker periodic acid-Schiff (PAS) dual staining to see if VM existing in these tumors. The results demonstrated that endothelium-lined vessels dominated the tumor microvasculature and stained positively for PAS, laminin, and endothelial marker. PAS-positive pattern of VM was found in two grade IV astrocytomas. Channels stained positively for PAS, laminin, and negatively for CD34 of the VM entrapped in the tumor tissue. Erythrocytes could be observed in some of these channels. In these networks of PAS-positive pattern, spots of weak reaction for CD34 were observed, suggesting the incorporation of VM channel and normal vessel. Furthermore, in astrocytoma, especially glioblastoma, focus of anaplastic tumor cells appeared with CD34 expression, whereas some tumor cells lost glial fibrillary acid protein expression. It is assumed that genetically deregulated tumor cells in astrocytoma could lose the astrocyte-specific protein and express inappropriate markers not expected in cells of astrocyte lineage. The present results suggest that VM phenomenon exists in some malignant astrocytoma.