Detection of chromosomal imbalances in papillary bladder tumors by comparative genomic hybridization

Objectives, To identify those genetic alterations that are associated with bladder cancer invasion and progression. Methods. A total of 30 specimens of transitional cell carcinoma of the blad der were analyzed by comparative genomic hybridization, The results were co mpared and summarized with previously reported studies. Results, The most frequent chromosome changes detected in our series of tum ors were losses in 9q, 9p, 8p, and 11p and gains in 8q, 1q, 20q, and 11q. T hree regions of deletion on chromosome 9 were delineated, at 9p21-p22, 9q13 -q22, and 9q31-q34, Gains in 1q and losses on 11p were significantly more f requent in pT1G2 tumors than in superficial (pTa) ones. In our study, the m ost striking differences were seen between pT1G3 and pT1G2 tumors. Gains on 10p and 6p and losses at 5q, 6q, and 18q were significantly more frequent in the former. Conclusions. A summary of our results and those available from published re ports suggest that several groups of chromosomal imbalances may be associat ed with specific steps along bladder cancer progression. These genetic chan ges assume two different patterns: those that are shared, but are more inte nsive in one stage than in the other, and those such as a gain on 3p that a re unique to invasive tumors. UROLOGY 57: 986-992, 2001. (C) 2001, Elsevier Science Inc.