Distinct nonrandom patterns of chromosomal deletions in giant-cell lesions of bone

Cytogenetic analyses were performed on a bone giant cell reparative granuloma (GCRG) and on three bone giant cell tumors (GCT). The present GCRG case is the second to be described cytogenetically. A modal chromosome number of 46 was observed in all samples. Clonal chromosome abnormalities were detected in all cases. The numerical alterations most frequently observed involved the loss of chromosomes 17 and 18. Among the structural anomalies observed, there was preferential involvement of chromosomes 6 and 10. Three GCT cases presented del(10)(p13) and two cases presented del(6)(q25) (1 GCRG and 1 GCT). These breakpoints mapped on 10p and 6q may harbour genes of importance in the development of bone giant cell tumors.