PCNA and Ki-67 in central nervous system tumors: correlation with the histological type and grade.

Determination of proteins in the control of proliferation in normal cells helps a better understanding of cellular transformation and proliferation mechanisms. Measurement of proliferative activity is important in determining the tumor grade, recurrence span and malignancy. Proliferating cell nuclear antigen (PCNA) and Ki-67 are two of the nuclear markers used to demonstrate the proliferative phase of the cell cycle. In the present study, 63 central nervous system (CNS) tumors of various histologic types, diagnosed in Cukurova University Medical Faculty. Department of Pathology and graded according to WHO grading system were examined for PCNA and Ki-67 monoclonal antibodies using immunohistochemistry. Results were analyzed with statistical methods. Distribution of PCNA and Ki-67 LI (labeling index) values were determined for different tumor types. The highest PCNA and Ki-67 LI values were detected in medulloblastoma, malignant meningioma, primitive neuroectodermal tumor (PNET) and glioblastoma (GBM) groups, while pilocytic astrocytoma, meningioma, craniopharyngioma and oligodendroglioma showed the lowest values. In such tumors, the correlation between the increasing grade and PCNA and Ki-67 LI values were statistically significant. A correlation between the clinical outcome and Ki-67 and PCNA LI values was also detected. Conclusively, both markers can be used to evaluate the tumor grade and to asses the possibility of recurrence and malignancy in CNS tumors.