Minimal regions of chromosomal imbalance in retinoblastoma detected by comparative genomic hybridization

Mutation of both alleles of the retinoblastoma gene (RBI) initiate oncogene sis in developing human retina, but other common genomic alterations are pr esent in the tumors. In order to sublocalize the altered genomic regions, 5 0 retinoblastoma tumors were examined by comparative genomic hybridization (CGH). The minimal regions most frequent gained were 1q31 (52%) 6p22 (44%), 2p24-p25 (30%) and 13q32-q34 (12%). The minimal region most frequently los t was 16q22 (14%). The overall total number of gains or losses evident on C GH was significantly greater in those tumors with either or both 6p or 1q g ain, than in tumors with neither 6p nor 1q gain suggesting that chromosomal instability may be associated with acquisition of these changes. Genes map ping to 6p22 and 1q31 may be important in tumor development in retina subse quent to the loss of RBI alleles. (C) 2001 Elsevier Science Inc. All rights reserved.