Evaluation of DNA content in preneoplastic changes of mouse urinary bladder induced by N-butyl-N-(4-hydroxybutyl) nitrosamine.

Using image cytometry analysis we analysed the deoxyribonucleic acid content of preneoplastic lesions induced in C3H/He female mice. Female mice (n = 30) were given 0.05% BBN in their drinking water for 4, 8 and 12 weeks, and were then euthanized. At the 4th week 90% hyperplasias, 90% dysplasias and 10% papillary tumours developed selectively in the bladder, after 8 weeks mice developed 80% hyperplasias and 80% dysplasias and 12 weeks we identified 70% hyperplasias, 70% dysplasias, 10% papillary tumours and 20% squamous metaplasia. Among the ones who developed simple hyperplasia, 58.3% were diploid and 41.7% were aneuploid. In the dysplasia lesions 29.2% were diploid and 70.8% were aneuploid (p = 0.041). All papillary tumours were aneuploid and all epidermoid metaplasias were diploid. These results suggest that aneuploidization, DNA content alteration of preneoplastic lesions, might be considered as a prognostic factor.