The karyotype of two human meningiomas are reported in which, besides other aberrations, a deleted chromosome 1 and 6 could be observed. In these chromosomes most of the short arm is missing. After silver staining for the detection of NORs, not only the satellite regions of most of the acrocentric chromosomes were stained but also the deleted ends of chromosomes 1 and 6. Besides other explanations for this unusual NOR-staining, the possibility is discussed that NORs of acrocentric chromosomes are easily translocated to deleted chromosomes.
Parts of this work are included in the doctoral thesis (M.D.) of H.H.