Prognostic Implications of the MIB-1 Labeling Index in Astrocytic Tumors

성상세포성 종양에서 MIB-1증식지수와 예후의 연관성

Objective : The proliferative potential of intracranial glioma affects the histological malignancy and prognosis of patients with these tumors. In this study, we present the relationship between MIB-1 labeling index(LI) and clinical variables which might play the major role in determining the prognosis of patient with astrocytic tumors. Patients and Methods : Excised tumor specimens from a total of 52 patients were stained to detect monoclonal MIB-1-Ki-67 antibody by avidin-biotin complex immunohistochemistry. The MIB-1 LI was evaluated with histological grades, demograpghic data, and survival time. The statistical significance of their correlation was analyzed by Pearson correlation test. Results : The 52 patients included 30 male patients and 22 female patients. The tumors according to the criteria of the World Health Organization(WHO) classification were verified as pleomorphic xanthoastrocytoma in one, pilocytic astrocytomas 4, astrocytomas 1, anaplastic astrocytomas 3, and glioblastomas 31. MIB-1 LI in astrocytic ttumors showed no correlation with age and gender. However, the patients under 10 years had the longest survival time, whereas short survival time was observed in the older patients. The mean MIB-1 LI of different tumor grades were as follows : pleomorphic xanthoastrocytoma, $4.40{\pm}0.00$ ; pilocytic astrocytoma, $4.53{\pm}3.09$ ; astrocytoma, $5.50{\pm}6.03$ ; anaplastic astrocytoma, $12.68{\pm}12.50$ ; Glioblastoma, $21.31{\pm}19.63$. Although the levels of MIB-1 LI were varied in individual tumors, the MIB-1 LI was increased in parallel with the histological grades. Glioblstomas showed significantly higher MIB-1 LI compared with that of anaplastic astrocytomas and low grade astrocytomas (p = 0.001). The mean survival time of entire group of patients was also well correlated with MIB-1 LI in astrocytic tumors(p = 0.015). Moreover, the mean survival time of the entire group of patients with Lis < 10 was $125.33{\pm}113.57weeks$, and the mean survival of those with $Lis{\geq}10$ was $60.71{\pm}62.58weeks$. This difference was also statistically significant(p = 0.004). Conclusion : The results of this study suggest that MIB-1 LI correlates with histological grades and might play a significant role in predicting the survival of patients with astrocytic tumors.