The erythrocyte-type glucose transporter in blood vessels of primary and metastatic brain tumors.

We previously demonstrated that brain microvessels have a high density of the erythrocyte-type glucose transporter and suggested this could be used as a marker of cells with "occluding" junctions. Now, we have studied by immunocytochemistry the tissue distribution of the glucose transporter in a variety of primary and metastatic human brain tumors with a monoclonal antibody to the glucose transporter of human erythrocytes. Microvessels in normal brain tissue distant from the tumor, and in brain surrounding the tumor, immunostained strongly for the glucose transporter. Microvessels in primary and metastatic tumors, however, lacked glucose transporter immunoreactivity. Only in the relatively benign juvenile cerebellar astrocytomas was glucose transporter immunoreactivity retained in some of the tumor microvessels. Because a high glucose transporter density is a marker of vessels with barrier properties, our results indicate that the vast majority of brain tumor microvessels do nc, have an intact blood-brain barrier.