CGH analysis of secondary genetic changes in Ewing tumors: correlation with metastatic disease in a series of 43 cases

The occurrence of secondary chromosome changes is frequent in Ewing tumors, in particular trisomies for chromosomes 8 and 12, and unbalanced (1; 16) t ranslocations leading to gains of 1q and losses of 16q. The prognostic valu e of these secondary aberrations has not been statistically demonstrated. W e report here a CGH analysis of a series of 43 primary tumors corresponding to 21 localized and 22 metastatic tumors. For five of them, a sufficient a mount of DNA for the CGH analysis was available from the frozen samples. Fo r 19 samples, a preliminary step of DOP-PCR amplification of the DNA was ne cessary. For the last 19 tumors, DNA was obtained after DOP-PCR amplificati on of small amount of DNA contaminating the RNA. As a whole, the main chrom osome imbalances previously described, such as trisomies for 1q 8, and 12, were observed. It is noteworthy that the mean number of imbalances was more frequent in localized versus metastatic tumors. Gain of lq was more freque nt in metastatic than in localized tumors. Nevertheless, these two results do not reach statistical significance. Conversely, a statistically signific ant excess of copy number of chromosome 2 was observed in non-metastatic tu mors, suggesting that this imbalance, which has never been previously repor ted, could be associated with more favorable tumor behavior. (C) 2001 Elsev ier Science Inc. All rights reserved.