Practical value of MIB-1 index in predicting behavior of astrocytomas.

Abstract
Background : The MIB-1 labeling index (LI) has proved to be useful in assigning grading and prognosis to astrocytomas. The purpose of our study was to analyze the utility of MIB-1 LI in differentiating astrocytomas of varying grades and the possible relationships of MIB-1 LI with clinical parameters like age and sex. We also wanted to study the prognostic role of MIB-1 index in predicting behavior of astrocytomas. Materials and Methods : Our study included 145 patients with astrocytic tumors of varying grades. Immunolabeling for all patients was done using MIB-1 antibody. Survival data could be obtained for 64 patients. A Mann-Whitney U test was used to test the difference in MIB-1 LI between different histological grades. The univariate analysis was done by the Kaplan-Meier method, and the multivariate analysis for survival was performed using the Cox proportional hazard model. Results : Significant differences were noted in mean MIB-1 LI of high-grade and low-grade diffuse astrocytomas. MIB-1 LI did not vary significantly with age and sex. Univariate analysis showed favorable prognostic factors for low histopathological grade, young patient age and low MIB-1 LI; however, multivariate analysis showed that only histopathological grade had independent prognostic significance. Conclusions : Our study proves that MIB-1 LI is not dependent on factors like age and sex and is solely dependent on histological grade. Though the average level of MIB-1 LI varies considerably in the different grades of astrocytomas, considerable overlap can be observed between them. MIB-1 LI is a very useful adjunct to the histopathological diagnosis and can be of great help in situations where the clinical and radiological findings do not correlate with histological diagnosis.
Description
Keywords
Astrocytomas, Ki-67, MIB-1 LI, prognostic value
Citation
Ambroise M Moses, Khosla Charu, Ghosh Mitra, Mallikarjuna V S, Annapurneswari S. Practical value of MIB-1 index in predicting behavior of astrocytomas. Indian Journal of Pathology & Microbiology. 2011 Jul-Sept 54(3): 520-525.