[KI-67 PAP stain for histologic grading of brain tumors by squash preparations]

Using Ki-67 monoclonal antibody to the nuclear antigen of proliferating cells, the squash preparations of 141 brain tumors and the 36 frozen sections from corresponding tumor tissues were stained with peroxidase-antiperoxidase method. The staining indices in squash preparations correlated well to those in the corresponding frozen sections. There were good correlations between the percentage of stained cells and the histologic grade in agreement with known biologic behavior. In order of decreasing malignancy, the averages of Ki-67 staining indices were 26.7% for metastatic carcinomas, 12.6% for glioblastomas, and less than 2.8% for benign mesodermal tumor groups. Ki-67 staining with squash preparations could be applied to small tissues obtained by transsphenoidal surgery and stereotactic surgery as valuable adjuncts to intraoperative histologic diagnosis and the estimation of histologic malignancy.