Examination of tumorigenesis of precursor lesions in bladder cancer by in situ hybridization.

Through examinations using fluorescence in situ hybridization (FISH) of chromosomes 1 and 9, we tried to obtain more information on dysplasia and carcinoma in situ (Cis) in relation to the oncogenesis of bladder cancer. 63 paraffin sections (dysplasia grades I-III and Cis) were evaluated, and 8 negative sections functioned as a control group. For FISH, DNA samples of CEP 1 and 9 (alpha satellites) were chosen. Gains (aneuploidy) or losses (monosomy) of chromosomal material were determined microscopically. Dysplasia grades I-III showed a 5-18% aberration in chromosome 1 aneuploidy and a 19-29% aberration in monosomy 9. Cis revealed 27% aneuploidy of chromosomes 1 and 9. Although at present dysplasia grade III and Cis of the bladder are viewed as histopathologically identical, we examined both molecular genetic differences in chromosome 9. As referred to in the literature we found the same genetic aberrations for dysplasias (grades I-III) and noninvasive papillary bladder tumors as well as for Cis and solid invasive bladder cancer.