[Immunohistochemical study of proliferation index of astrocytomas classified by new histopathological grading].

A new grading method of astrocytoma, proposed by Daumas-Duport et al, was based on four criteria:nuclear atypia, mitosis, necrosis and endothelial proliferation (0 criteria = Grade 1, 1 criteria = Grade 2, 2 criteria = Grade 3, 3 or 4 criteria = Grade 4). To elucidate the correlation of the classification based on four criteria, cellularity and proliferative activities, we studied proliferating index of 67 astrocytomas, using immunohistochemical staining for Ki-67 antibodies (MIB-1). A new grading method was related to proliferating index in this study, however, cellularity of tumor cells was not related to proliferating index. In this study, endothelial proliferation was invariably seen in high grade(Grade 3 and 4) astrocytomas. These tumor vessels were associated with dysfunction of blood-brain barrier and some growth factors accelerated to tumor cell proliferation. Relation between histopathological grade of astrocytoma and proliferation index was supposed, and new grading system was thought to be useful for routine pathological examination.