Altered expression of antithrombotic molecules in human glioma vessels.

A total of 14 surgical specimens, including 7 glioblastomas, 3 anaplastic astrocytomas, 2 brains adjacent to glioblastoma and 2 grossly normal brains, were investigated immunohistochemically for the expression of antithrombin III (AT-III), heparan sulfate proteoglycan (HSPG) and thrombomodulin (TM) in the endothelium of microvessels. The immunoreaction to AT-III was of moderate intensity in grossly normal brains, brains adjacent to glioblastoma, and anaplastic astrocytomas, but was only weak in glioblastomas, especially in the capillaries. The immunoreaction to HSPG was constantly intense in the microvessels in all the specimens. Although the immunoreaction to TM was negative or only faint in the microvessels in grossly normal brains, it was moderately to strongly intense in anaplastic astrocytomas and brains adjacent to glioblastoma. The intensity of immunoreaction to TM was variable, from faint to strong in the capillaries, and moderate to strong in larger microvessels in glioblastomas. The present study suggested that the alterations in the expression of those antithrombotic molecules could explain, at least in part, the tendencies for intratumoral hemorrhage as well as intravascular thrombosis in the different areas of malignant gliomas.