Determination of proliferative activities in human brain tumor specimens: a comparison of three methods

Proliferative activities were determined in 72 human brain tumors, including 20 metastatic carcinomas, 41 gliomas, 8 meningiomas and 3 hematological tumors. Immunocytochemical techniques included labeling with monoclonal antibody (mAb) to bromodeoxyuridine (BrdU) which identifies S phase cells after previous in vitro BrdU incubation and paraffin embedding of fixed tissue specimens, and with mAb Ki-67 which reacts, in frozen sections, with a nuclear antigen expressed by all proliferating cells. BrdU labeling index (LI), Ki-67 LI and mitotic index (MI) correlated well with histological malignancy. Among the three proliferation indices, Ki-67 LI and BrdU LI were highly significantly correlated. With the exception of hematological malignancies, hyperbaric oxygenation of in vitro BrdU labeling did not significantly increase BrdU LI or depth of BrdU penetration into tissue. This study indicates that in vitro BrdU labeling is a useful alternative to Ki-67 immunolabeling of human brain tumor specimens. By such determination of tumor proliferation, it might be possible to design a more adequate postoperative therapy tailored to patients individually.