Clinical significance of genetic imbalances revealed by comparative genomic hybridization in chondrosarcomas

DNA copy number changes were studied by comparative genomic hybridization (CGH) in 50 chondrosarcoma samples from 45 patients. Mean number of genetic aberrations in primary tumors was 4.8 +/- 1.8. The most frequently gained regions were 20q12-qter (37%), 20q (32%), 8q24.1-qter (27%), 20p (24%), and 14q24-qter (24%). Losses were 5.5 times less frequent than gains and observed mainly at Xcen-q21, 6cen-q22, and 18cen-q11.2 (11% each). Recurrent and metastatic tumors showed a mean of 4.0 +/- 2.2 aberrations per sample. The most frequently gained regions were chromosome 7 (4 cases), 5q14-q32 (4 cases), 6p (3 cases), and 12q (3 cases). Losses of DNA sequences were 3.4 times less frequent than gains. Histological tumor grade was significantly associated with metastasis-free survival (P = .002) and overall survival (P = .003), being the strongest prognostic factor tested. A statistically significant correlation was found between gain at 8q24.1-qter and shorter overall survival (P = .01) but not with local recurrence or metastasis-free survival. Gain at 14q24-qter was associated with a trend to shorter overall survival (P = .05) but neither with an increased risk for local recurrence nor with metastasis-free survival. In a multivariate analysis, only the tumor grade associated with overall survival (P = .02). In a multivariate analysis together with the tumor grade, gain at 8q24.1-qter did not retain its significance (P = .44), indicating that this imbalance is not an independent prognostic factor.