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.