Incidence and origin of dicentric chromosomes in cultured meningiomas.

Based on the cytogenetic findings in 32 human meningiomas, an analysis of dicentric chromosomes, usually present in cultures from meningiomas, has been performed. The incidence and origin of such markers have been analyzed and the chromosomal composition of the stem line in the corresponding sample established (i.e., normal karyotype, -22 as the sole chromosomal deviation, or complex karyotypes in addition to #22 abnormalities). More than 10 dicentric chromosomes were found in 12 of 32 meningiomas (37.5%). Sixty-eight of the markers could be identified individually or as belonging to a chromosome group. Fifty-three percent of the meningiomas characterized by a complex stem line karyotype also displayed dicentric chromosomes in variant cells, whereas only 12.5% of meningiomas with a normal diploid stem line showed such chromosomal aberrations. Chromosomes of groups C and D participated most frequently in the genesis of dicentrics; however, chromosomes 19, 20, 3, 6, and 13 were the most frequently involved. Thus, the existence of a nonrandom pattern of involvement supports the fact that dicentrics might play a biologic role in the progression of human meningiomas.