CYTOGENETIC ABERRATIONS IN OSTEOSARCOMAS - NONRANDOM DELETIONS, RINGS, AND DOUBLE-MINUTE CHROMOSOMES

Relatively few karyotypes have been reported from short-term cultures and/or direct harvests of osteosarcomas. We describe clonal aberration s in 17 high-grade osteosarcoma specimens and in one low-grade osteosa rcoma. The high-grade osteosarcomas were karyotyped after direct harve st (four cases) or after short-term culture periods of <1 week (13 cas es). Three of these specimens, a primary osteosarcoma and two lung met astases, were from the same patient and shared a number of clonal aber rations. No consistent chromosome translocations were identified in th e overall group of high-grade osteosarcomas, but potential nonrandom d eletions involved 6q21->qter, 9p21->pter, chromosome 10, chromosome 13 , 17p12-pter, and chromosome 20. Ring chromosomes were detected in thr ee cases, and double-minute (dmin) chromosomes were detected in six. A ll high-grade osteosarcomas had numerous nonclonal chromosome aberrati ons superimposed on complex clonal events. The single low-grade osteos arcoma was characterized by a balanced, nonconstitutional, t(5;10) (p1 3;p14-15), together with an addition to the short arm of chromosome X. This is the first translocation reported in low-grade osteosarcoma, a nd the simplicity of the karyotype contrasts strikingly with those in the high-grade osteosarcomas.