Although recurrent chromosome abnormalities have been identified in several histologic subtypes of sarcomas, no consistent rearrangement has yet been found in osteosarcomas. Cytogenetic analyses of nine cases of osteosarcoma are reported, including seven newly diagnosed tumors and two recurrent tumors. There were seven high-grade osteosarcomas, one periosteal osteosarcoma, and one well-differentiated sarcoma. All tumors were studied in short-term primary culture. Modal number ranged from near diploid t o near triploid. Seven tumors had complex karyotypes with multiple structural abnormalities; two had only normal karyotypes. The retinoblastoma gene on chromosome I 3 and the TP53 gene on chromosome I7 have been involved in osteosarcoma. Five tumors had loss of a whole copy of chromosome I 3, and three of these also had a l oss of a whole copy of chromosome 17. However, these losses were observed in the setting of numerous other chromosome loses.
Numerous structural abnormalities were observed, many involving additions of unidentified material, unbalanced translocations, or deletions. Structural abnormalities with similar breakpoints involving 6q, 8q, 9q, and I4p were seen in two or three tumors each. When the tumors in this series were added t o the 18 published cases, the pericentromeric regions of chromosomes I , 3, and 14, and segments 6q 15-2 I, 8q24,9q34, I2p I 3, I7p I 3, and 19q I 3, were found t o be involved in five or more structural rearrangements. Molecular analyses of these chromosome regions may yield genes important in the pathogenesis of osteosarcoma. Genes Chrorn Cancer 9:88-92 (1994).