Detection of chromosomal alterations in bladder cancer by comparative genomic hybridization

Objectives To characterize which genomic alterations occur in bladder cancers of different grades and stages, and to evaluate the prognostic implication of chromosomal imbalances. Materials and methods Twelve transitional cell carcinoma cell lines were used to study chromosomal aberrations, using comparative genomic hybridization to examine metaphase cells. Results There was a mean of 6.0 aberrations per tumour with 4.9 gains and 1.08 deletions per tumour cell line. The mean number of aberrations was the same in grade 2 and 3 tumours. High-stage ( greater than or equal to T2) carcinomas had markedly more genomic gains than had low-stage (T1) tumours, with 7.2 gains and 1.3 deletions per greater than or equal to T2 tumour, and 2.7 gains and 0.8 deletions per T1 tumour, although the difference was not statistically significant, The most frequent changes were gains of chromosome 1 (seven), 9 and 16 (six), and losses of chromosomes 14 (three), 21 and Y (two). The changes 1p+, 3p+, 9q+, 14p-, 16q+ and Yp-were significantly more frequent in low-grade tumours, with 1p+, 3p+ and Yq- the most frequent in stage T1 tumours, and 16p+, 9q+ and 13q- the most frequent in stage greater than or equal to T2 tumours. Conclusion These findings indicate several genomic regions in chromosomes 1, 9, 14 and 16 that may early genes for the development and progression of bladder cancers.