LOSS OF HETEROZYGOSITY FOR CHROMOSOME-22 DNA-SEQUENCES IN HUMAN MENINGIOMA

Monosomy of chromosome 22 in meningioma was the first consistent cytogenetic anomaly reported for a solid tumor. Although most meningiomas are isolated sporadic lesions, multiple and familial occurrences have been reported, usually in cases of documented neurofibromatosis 2 (NF2). Previous reports have placed the NF2 locus on chromosome 22, flanked by the markers D22S1 and D22S28. We report a restriction fragment-length polymorphism study of 16 meningiomas conducted using chromosome 22 probes. None of the patients had clinical findings or a family history of NF2, although two of them eventually developed multiple intracranial meningiomas. Detectable loss of chromosome 22 sequences was observed in 50% of informative patients. Deletion mapping of tumors with preserved sequences showed that the loss of chromosome 22 DNA overlapped the region previously linked to NF2, but also included a sequence distal to the NF2 locus. These results suggest that the oncogenesis of human meningioma involves inactivation of a chromosome 22 locus that may be in close proximity to the gene for NF2.