Chromosomal characteristics of neurogenic tumours in adults.

Abstract

The chromosomes in 50 cerebral and one cerebellar astrocytic gliomas, one oligodendroblastoma, and one medulloblastoma were studied in fixations directly from the tumours. The results permitted a detailed characterization of the chromosomal spectrum in cerebral astrocytic gliomas. About three quarters of them had diploid-near-diploid stemlines, and the near-tetraploids were more than twice as common as the near-triploids. In the diploid region the stemline numbers showed a bimodal distribution, with one peak at 47 and the other at 44–45. Among the polyploid stemline numbers there was a flat mode in the hypotetraploid-hypertriploid region. In the stemline karyotypes, deviations concerning ordinary chromosome groups were concentrated to groups C and D; approximately three quarters of the gliomas had one or several markers in their stemline. A special marker type, double-minutes, was seen in all or most cells in 4 gliomas. In 9 additional gliomas there were sporadic cells with this aberration. As regards ordinary marker types, the findings suggested an origin from chromosomes of groups C and D, particularly. The chromosomal findings were related to the histological picture of the cerebral gliomas. The chromosomal picture, however, seemed also to be influenced by the location of the glioma, the age and sex of the patients, and probably also by the duration of symptoms prior to operation.