[Analysis of proliferating cell nuclear antigen (PCNA) expression in brain tumors].

The expression of PCNA in brain tumor cells was measured in vitro and in situ by using an electrophoretical immunoblotting method and an immunohistochemical staining method. In synchronized C6 rat glioma cells, PCNA were almost parallel to the S phase, although the small amounts of PCNA were expressed in G1 and G2 x M phases. In astrocytic tumors from operative tissues, immunohistochemical PCNA positive rate increased significantly with increasing tumor grade. PCNA positive rate of recurrent meningiomas was also significantly higher than that in nonrecurrent meningiomas. These findings suggest that the PCNA is associated with the cell cycle, especially the S phase and immunohistochemical staining of PCNA is useful to evaluate the proliferating activity of a brain tumor. Immunoblotting method would also be helpful for the exact analysis of proliferating activity in brain tumor cells.