Proliferative potentials of glioma cells and vascular components determined with monoclonal antibody MIB-1

Proliferative activity in 78 glioma specimens was assessed immunohistochemically by determining proliferating index of tumor cells (PTC-PI) and endothelial cells (PEC-PI) using the MIB-1 monoclonal antibody. The PTC-PI of anaplastic astrocytoma (9.0 +/- 5.8: mean +/- standard deviation) was significantly higher than that of astrocytoma (1.2 +/- 0.4, < 0.01), and lower than that of glioblastoma multiforme (12.0 +/- 5.6, < 0.05). We then compared PTC-PI values, patients' age and extent of tumor resection with the prognosis of patients with malignant glioma (both glioblastoma and anaplastic astrocytoma). Kaplan-Meier survival rate analysis demonstrated higher survival rates in patients with less than 8.0% of PTC-PI at 5 and 10 years (p < 0.05). The mean age of patients who survived more than a year was lower than that of patients who died within a year (53.0 y.o., vs. 59.7 y.o., p < 0.01). Total or subtotal resection of the tumor was more often performed in the former than latter patients (51% vs. 21%, p < 0.01). These results suggested PTC-PI provides useful information which may allow better assessment of the biological behavior and clinical prognosis of glioma, in addition to histological grading, patients' age and extent of tumor resection. While the average PEC-PI value (3.3) was lower than that of PTC-PI (7.0), there was a significantly close relationship between PTC- and PEC values (p < 0.01), providing an impetus to develop novel therapies directed toward suppression of microvascular regeneration.