CORRELATION BETWEEN THE BROMODEOXYURIDINE LABELING INDEX AND THE MIB-1 AND KI-67 PROLIFERATING CELL INDEXES IN CEREBRAL GLIOMAS

Background. Recently, it has been shown that heating paraffin embedded tumor sections in a microwave oven can reactivate an epitope of Ki-67 protein that is recognized by the monoclonal antibody MIB-1. With thi s technique, a close correlation was shown between the bromodeoxyuridi ne labeling index (BUdR LI) and the MIB-1 proliferating cell index (PC I) in corresponding regions of glioblastomas. Methods. The reliability of the MIB-1 PCI as a marker of proliferation was evaluated in 90 cer ebral gliomas. The MIB-1 immunostaining of ethanol-fixed, paraffin emb edded sections of 23 moderately anaplastic astrocytomas, 22 highly ana plastic astrocytomas, 30 glioblastomas, and 15 mixed malignant gliomas was compared with the BUdR LI and, in some cases, the Ki-67 PCI. Resu lts. MIB-1 positive cells were detected easily in the majority of the cases, and the MIB-1 immunostaining was often superior to that of Ki-6 7 in individual tumors. The MIB-1 PCI was significantly higher than th e Ki-67 PCI and the BUdR LI. Linear-regression analysis showed signifi cant correlations among the three indices. The MIB-1 PCI was correlate d with the BUdR LI in each group of the astrocytic tumors and mixed ma lignant gliomas; the MIB-1 PCI was approximately 2.4-2.8 times higher than the BUdR LI. Conclusions. The close correlation between the MIB-1 PCI and the in vivo BUdR LI in serial sections of glioma subtypes sug gests that MIB-1 immunostaining is a useful technique for analyzing th e proliferative potential of individual gliomas.