[Measurement of PCNA labeling index in astrocytic tumors]

PCNA (proliferating cell nuclear antigen) is said to be present specifically in the nucleus of proliferating cells. The PCNA labeling index (PCNA LI) of astrocytic tumors was measured and compared with histological types or prognosis. The specimens from 44 patients were fixed in a 10% formalin solution, and embedded in paraffin. The 3 microns-sections were stained immunohistochemically with anti-PCNA monoclonal antibody (PCIO, Novocastra) using an ABC method. The percentage of PCNA-positive-cells was determined by counting 2000 cells, and identified as PCNA LI. All of the PCNA-positive-cells showed diffuse nucleoplasmic staining. The averages of PCNA LIs in each pathological type were calculated and evaluated statistically. Although differences in averages of PCNA LIs among pilocytic, gemistocytic, fibrillary astrocytoma were not significant, there was a significant difference between anaplastic astrocytoma and glioblastoma. The relationship between PCNA LIs and the prognoses for 43 patients was studied. Forty-three patients were classified into 3 groups (over 22%, 7 to less than 22%, and less than 7%) according to PCNA LIs. The survival data in the 3 groups were analyzed, and differed significantly in the survival rates. Furthermore, twenty-three patients of anaplastic astrocytoma and glioblastoma were classified into two groups (over 22% and less than 22%). Likewise, the two groups differed significantly. In summary, pathological type and prognosis were closely related to PCNA LI in astrocytic tumors. Therefore, we thought measurement of PCNA LI would make it more possible to analyze clinically the proliferating activity of astrocytic tumors, and to care for patients more effectively.