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Published on: July 31, 2017
Correlation between histological grade and MIB-1 and p53 immunoreactivity in meningiomas
O Ozen1, B Demirhan, N Altinörs
1Department of Pathology, Baskent University Faculty of Medicine, Ankara, Turkey. ozlemo@baskent-ank.edu.tr
Objective:
Meningiomas for the most part are slow-growing benign tumors, but complete removal can be difficult and recurrence is an issue. The aim of this study was to re-evaluate tumors diagnosed as meningioma previously in our hospital, according to the latest World Health Organization classification. We also examined the relationships among parameters such as brain invasion, histological grade and Ki-67 and p53 expression in these tumors.
Materials And Methods:
Meningioma biopsy specimens numbering 60 (48 grade I, 11 grade II, and 1 grade III tumors) were examined immunohistochemically using monoclonal antibodies for Ki-67 (MIB-1) and p53 protein. The MIB-1 labeling index (LI) for each tumor was calculated as a percentage based on the number of stained cells per total cells counted. The level of p53 expression in each sample was semiquantatively evaluated as < 1%, 1 - 10%, 10 - 70%, or > 70%. Any value > 1% was accepted as presence of p53 expression.
Results:
Of the 60 meningiomas, 7 (11.7%) exhibited brain invasion. The mean MIB-1 LI values for the grade I and grade II tumors were 1.1% and 2.3%, respectively. The corresponding levels of p53 protein expression in these groups were 54.1% and 72.7%. The MIB-1 LI and the level of p53 expression in the one grade III meningioma were 6.7% and 10 - 70%, respectively. Histological grade was significantly correlated with MIB-1 LI and with p53 expression (p < 0.01 for both). Brain invasion was not correlated with histological grade, MIB-1 LI, or p53 expression.
Conclusion:
The results indicate that MIB-1 LI and p53 protein expression are good indicators of histological grade in meningioma and may be particularly valuable for distinguishing borderline atypical meningiomas. The number of cases was limited, but the findings also suggest that brain invasion is a prognostic parameter independent of grade, MIB-1 LI and p53 expression.
Insights
Ki-67 (MIB-1) labeling index and p53 protein expression effectively indicate meningioma histological grade. Brain invasion appears to be an independent prognostic factor, even in cases with similar MIB-1 LI and p53 expression.
Area of Science:
- Neuro-oncology
- Tumor Biology
- Surgical Pathology
Background:
- Meningiomas are typically slow-growing tumors, but complete resection and recurrence remain significant clinical challenges.
- Accurate grading is crucial for predicting meningioma behavior and guiding treatment strategies.
- Re-evaluation based on the latest World Health Organization (WHO) classification is essential for refining diagnoses.
Purpose of the Study:
- To re-evaluate previously diagnosed meningiomas using the current WHO classification.
- To investigate the correlation between histological grade, brain invasion, and the expression of Ki-67 (MIB-1) and p53.
- To assess the prognostic value of these markers in meningioma management.
Main Methods:
- Immunohistochemical analysis of 60 meningioma biopsy specimens (48 grade I, 11 grade II, 1 grade III).
- Assessment of Ki-67 labeling index (LI) and semiquantitative evaluation of p53 protein expression.
- Statistical analysis to determine correlations between histological grade, brain invasion, MIB-1 LI, and p53 expression.
Main Results:
- Seven out of 60 meningiomas (11.7%) showed brain invasion.
- Significant correlations were observed between histological grade and both MIB-1 LI (mean 1.1% for grade I, 2.3% for grade II) and p53 expression (54.1% for grade I, 72.7% for grade II).
- Brain invasion did not correlate with histological grade, MIB-1 LI, or p53 expression.
Conclusions:
- MIB-1 LI and p53 protein expression are valuable indicators of meningioma histological grade, particularly for differentiating atypical (borderline) tumors.
- Brain invasion may represent a prognostic parameter independent of tumor grade and molecular markers.
- Further studies with larger cohorts are warranted to confirm the prognostic significance of brain invasion.
