IDENTIFICATION OF GAINS AND LOSSES OF DNA-SEQUENCES IN PRIMARY BLADDER-CANCER BY COMPARATIVE GENOMIC HYBRIDIZATION

Comparative genomic hybridization (CGH) makes it possible to detect lo sses and gains of DNA sequences along all chromosomes in a tumor speci men based on the hybridization of differentially labeled tumor and nor mal DNA to normal human metaphase chromosomes. In this study, CGH anal ysis was applied to the identification of genomic imbalances in 26 bla dder cancers in order to gain information on the genetic events underl ying the development and progression of this malignancy. Losses affect ing 11p, 11q, 8p, 9, 17p, 3p, and 12q were all seen in more than 20% o f the tumors. The minimal common region of loss in each chromosome was identified based on the analysis of overlapping deletions in differen t tumors. Gains of DNA sequences were most often found at chromosomal regions distinct from the locations of currently known oncogenes. The bands involved in more than 10% of the tumors were 8q21, 13q21-q34, 1q 31, 3q24-q26, and 1p22. in conclusion, these CGH data highlight severa l previously unreported genetic alterations in bladder cancer. Further detailed studies of these regions with specific molecular genetic tec hniques may lead to the identification of tumor suppressor genes and o ncogenes that play an important role in bladder tumorigenesis. (C) 199 5 Wiley-Liss, Inc.