P53 overexpression and proliferative potential in malignant meningiomas

Area of Science:

• Neuro-oncology
• Molecular pathology
• Cancer biology

Background:

• Meningiomas, typically benign, can exhibit malignant traits like invasion and recurrence.
• Understanding the molecular mechanisms driving meningioma malignancy is crucial for improved patient outcomes.

Purpose of the Study:

• To investigate the role of p53 protein alterations in the malignant progression of meningiomas.
• To correlate p53 protein levels and mutations with meningioma grade, proliferative potential, and recurrence rates.

Main Methods:

• Immunohistochemistry using monoclonal antibodies (DO-1 and pAb240) to detect p53 protein in 61 meningioma samples.
• Immunoblot analysis for p53 protein quantification.
• Single-strand conformational polymorphism (SSCP) analysis to assess p53 gene mutations.
• MIB-1 immunostaining to evaluate tumor proliferative activity.

Main Results:

• Overexpression of p53 protein was observed in all anaplastic meningiomas, but rarely in benign or atypical types.
• Higher p53 staining index and protein levels correlated with increased tumor grade and recurrence.
• MIB-1 index positively correlated with tumor grade and p53 overexpression.
• Analysis indicated that the overexpressed p53 protein was predominantly wild-type, not mutant.
• Anaplastic meningiomas with p53 overexpression showed repeated recurrences despite treatment.

Conclusions:

• Accumulation of wild-type p53 protein, alongside high proliferative potential, is a characteristic feature of malignant meningiomas.
• p53 protein overexpression may serve as a biomarker for predicting aggressive biological behavior and recurrence in meningiomas.