The significance of immunohistochemical expression of Ki-67, p53, p21, and p16 in meningiomas tissue arrays.

Although histologic grading of meningiomas has prognostic and clinical implications, it is difficult in some cases to predict the outcome of patients. There have been several efforts to evaluate the use of different immunohistochemical markers for predicting meningioma prognosis. We analyzed the immunohistochemical expression of Ki-67, p53, p21, p16, and PTEN proteins in 130 meningiomas (64 benign, 39 atypical, and 27 malignant meningiomas) using tissue microarray. The tumors were graded according to the World Health Organization classification. There was a statistically significant correlation between the expression of Ki-67, p53, p21, p16, and the grade of meningiomas (p0.001). By ordinal logistic regression, p53 and Ki-67 were significantly associated with grade, and an increase of 1% in the labeling index of these markers resulted in an increase in the risk of raising the grade by 2.17 and 1.49, respectively. Histological grade, p53, Ki-67 labeling indices, and overexpression of p16 were strongly associated with decreased event-free survival in univariate analysis. In contrast, multivariate analysis revealed that only tumor grade is an independent factor for predicting meningioma recurrence. We conclude that the Ki-67 and p53 labeling indices are useful additional tools in discriminating atypical from benign or anaplastic meningiomas, especially in histological borderline cases.