Cytogenetic and in situ DNA-hybridization studies in intracranial tumors of a patient with central neurofibromatosis.

We have studied a meningioma and an acoustic neurinoma of a patient with central neurofibromatosis. In the meningioma cells, one chromosome 22 was replaced by an almost metacentric, bisatellited marker chromosome that appeared monocentric after CBG-staining. In situ hybridization with a chromosome 22 centromere specific DNA probe (p22hom48.4) revealed specific signals in the pericentromeric region of the marker chromosome, indicating the presence of at least the short arm and the centromere of chromosome 22. The pericentromeric localization of the hybridization signals suggest the marker consists of an isoformation of the short arm of chromosome 22, resulting in a monosomy for the long arm of chromosome 22. In contrast to these findings in meningioma cells, no chromosomal abnormality could be detected in acoustic neurinoma cells. Our findings provide further evidence that loss of genetic material on the long arm of chromosome 22 is associated with the development of central neurofibromatosis.