Detection of chromosome imbalances in retinoblastoma by parallel karyotypeand CGH analyses

We have studied a series of 20 primary retinoblastomas by karyotypic analys is and comparative genomic hybridization (CGH), to perform an exhaustive ev aluation of chromosome imbalances in this tumor. In addition, 4 tumors were studied by CGH only. On the whole, CGH results were largely in agreement w ith those of karyotypic analysis and with known cytogenetic data. The most frequent imbalances were +6p (13/24 cases), +1q (12/24), -16/-16q (11/24), and +2p (9/24). Recurrent high-level amplifications were observed in 2p23-2 5 and 1q21. Amplification of 2p23-25, present in 4 cases among which 3 show ed double-minute chromosomes, was related to MYCN amplification, as demonst rated by FISH and PCR. No evident correlation was found in this small serie s between any of the imbalances identified and either the differentiation o r the histoprognostic risk. (C) 2000 Wiley-Liss, Inc.