Abstract
The Ki-67 labeling index and p53 overexpression determined with immunohistochemistry are both useful indicators of the cellular proliferative potential of brain tumors. We compared the immunohistochemical expression of Ki-67 and p53 proteins in samples of 20 astrocytomas obtained from 19 patients which had been pretreated with three different methods of antigen activation: 95°C heating, 121°C autoclaving, and exposure to target unmasking fluid. The Ki-67 labeling index of specimens pretreated with autoclaving and 95°C heating was positively correlated with the degree of malignancy of astro-cytomas (simple regression analysis, p<0.002 for autoclaving and p<0.03 for 95°C heating) . p53 overexpression was identified in 7 astrocytomas (2 cases of low-grade astrocytomas, 2 cases of anaplastic astrocytomas, and 3 cases of glioblastoma multif ormes) ; however, p53 expression was not correlated with the degree of malignancy of astrocytomas.
