Anaplastic and atypical meningiomas express high levels of Fas and undergoapoptosis in response to Fas ligation

In this study we characterized the expression of Fas and Fas ligand in diff erent types of meningiomas and examined the effect of Fas ligation on the d eath of meningioma cells in culture. Using Western blot analysis, we found that extracts derived from anaplastic and atypical meningiomas expressed hi gh levels of Fas, whereas benign meningiomas did not express detectable lev els of this protein. All of the meningiomas examined expressed low levels o f Fas ligand. Cultures of anaplastic meningiomas also expressed Fas and tre atment of these cells with anti-Fas antibody induced cell death. The result s of this study indicate that Fas is preferentially expressed in atypical a nd anaplastic meningiomas and suggest that it is involved in the increased apoptosis observed in these tumors.