We investigated glioblastoma multiforme (GEM) for a pattern of consistent alterations in cell adhesion molecules (CAM) expression that might distinguish tumor from normal autologous brain tissue. We used frozen section immunohistochemistry with anti-CAM and computerized image analysis to quantify staining intensity which we expressed as relative intensity units (RIU). Our results showed that normal brain tissue generally did not express alpha(1) beta(1), intercellular CAM-1 (ICAM-1), and sialylated Lewis(x), slightly expressed alpha(2), alpha(4), alpha(5), alpha(6) beta(1), alpha(v) beta(3), lymphocyte function-associated antigen-3 (LFA-3), Lewis(x), sialylated LewisLewis(x), had a good expression of alpha(3) beta(1) and CD44, and strongly expressed neural CAM (NCAM). GBM expressed alpha(2), alpha(3), alpha(5), alpha(6) beta(3), ICAM-1, LFA-3, CD44, Lewis(x), sialylated Lewis(x), and sialylated LewisLewis(x) significantly higher (2-11-fold RIU) than normal brain tissue. ICAM-1 and LFA-3 were the most distinctive markers of GBM. The small blood vessel endothelial cells of the normal brain and the GBM showed a few differences. The tumor endothelium expression of alpha(2) beta(1), alpha(4) beta(1), and LFA-3 RIU appeared twice higher than in normal endothelium and alpha(6) beta(1) showed an average of 40% RIU decrease in comparison to normal. These results show that the expression of several CAM is consistently altered in GBM and its microvasculature when compared with autologous normal brain tissue.