Role of Ki-67 labeling index as an adjunct to the histopathological diagnosis and grading of astrocytomas

AIM OF THE STUDY: Ki-67 labeling index (LI) is used in the assessment of cell proliferating activity. It has been widely documented for various human tumors, including the brain neoplasms. The aim of the present study is to evaluate Ki-67 as proliferative index in the grading of astrocytomas in order to predict the biological behavior of the tumor and prognosis of patients. MATERIALS AND METHODS: In the present study, a total of 105 patients with astrocytomas were included. Ki-67 LI was done on all the astrocytomas and was compared in correlation with World Health Organization histological grading of astrocytomas. RESULTS: The mean Ki-67 LI in Grade I astrocytomas was 3.36 ± 4.59 standard deviation (SD), 7.05 ± 4.16 SD in Grade II astrocytomas, 28.24 ± 6.23 SD in Grade III astrocytomas and 38.7 ± 7.19 SD in Grade IV astrocytomas. P values were significant between all grades of astrocytomas except between Grade I and Grade II tumors which was 0.5076. CONCLUSIONS: Assessment of astrocytic tumor proliferative potential provides important prognostic information that supplements standard histological grading. Ki-67 LI is the simplest and most reliable methods of all. This study demonstrates that, Ki-67 LI serves as an important prognostic marker in human astrocytomas. Ki-67 LI solely correlates with a grade of the tumor. Average level of Ki-67 LI varies between different grades of astrocytic tumors but some overlap of values does exist.