EVIDENCE FOR THE COMPLETE INACTIVATION OF THE NF2 GENE IN THE MAJORITY OF SPORADIC MENINGIOMAS

Meningiomas are common central nervous system tumours which present us ually in the 4th and 5th decades of life. Loss of constitutional heter ozygosity on chromosome 22 in 60% of sporadic meningiomas has implied the involvement of a tumour suppressor gene. The neurofibromatosis typ e 2 gene (NF2), a prime candidate for involvement in meningioma, was s creened for point mutations. After examining eight of the 16 known NF2 exons in 151 meningiomas, 24 inactivating mutations were characterize d. Significantly, these aberrations were exclusively detected in tumou rs which lost the other chromosome 22 allele. These results provide st rong evidence that the suppressor gene on chromosome 22, frequently in activated in meningioma, is the NF2 gene, and suggest that another gen e is involved in the development of 40% of meningiomas.