Chromosomal analysis of bladder cancer. III. Nonrandom alterations.

Chromosome analysis using G- and C-banding was performed on 13 primary transitional cell carcinomas of the bladder. The chromosome preparations were obtained by a direct method. In eight tumors with a (near) diploid modal chromosome number, the most frequently observed chromosome aberrations were: (partial) monosomy 9 in four cases, deletion of 10q in two cases, and partial trisomy 1 in two cases. In five tumors with a modal chromosome number in the triploid or tetraploid range the chromosomes #1, #3, #7, #9, #11, and #17 were numerically and or structurally abnormal in at least four cases. In three out of ten males, the Y chromosome was missing. These findings suggest that the loss of chromosome #9, and possibly also loss of 10q is a primary event in the karyotypic evolution of transitional cell carcinoma of the bladder.