CHROMOSOME REARRANGEMENTS AT 12Q13 IN 2 CASES OF CHONDROSARCOMAS

We analyzed the karyotypes of two moderately differentiated [grade 2] chondrosarcomas. Case 1 had a reciprocal translocation between chromosomes 6 and 12, t[6;12][q25;q13] in most of the cells analyzed, as well as trisomies of chromosomes 7, 8, 11, 17, 19, and 21 and tetrasomy of chromosome 19. A reciprocal translocation involving chromosomes 12 and 19, t[12;19][q13;q13], was noted as a highly clonal abnormality in the other case. Some cells had t[12;19] as the sole chromosome abnormality. Thus, chromosome rearrangements involving the long arm of chromosome 12 at the same region [q13] were commonly identified in the two tumors. These findings suggest that the rearrangements at 12q13 are nonrandom acquired changes that characterize a subgroup of chondrosarcomas.