Mice: An Animal Model for Bladder Cancer

Background: Bladder cancer is a common malignancy and an important cause of morbidity and mortality in western world. Animal models are the centre of experimental researches aiming to elucidate our knowledge about carcinogenesis, its treatment and prevention. Mice have a lower urinary tract comparable to humans. Methods: 22 ICR male mice were randomized into two groups (I and II). Group I was the negative control drinking tap water, and group II received N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) in drinking water during twelve weeks. Euthanasia was executed one week after BBN exposition. Results: All animals from Group I exhibited normal urothelium. In Group II, 100% of animals exhibited histological changes. 62.79% were preneoplastic lesions (simple hyperplasia, nodular hyperplasia, dysplasia) and 37.21% were neoplastic lesions (carcinoma in situ, invasive carcinoma, epidermoid metaplasia). Conclusions: Experimental urinary bladder tumours are useful models for the study of urinary bladder carcinogenesis and for the evaluation of new therapeutic strategies. In mice, chemically induced bladder cancer is nearly always of the invasive type and the incidence of spontaneous tumours is very rare. The similarity between human’s and mice’s bladder cancer allows the investigation of several aspects that can’t be studied under clinical conditions, such as pharmacokinetics and toxicity. This work was supported by Portuguese Foundation for Science and Technology, Center for Studies in Education, Technologies and by Health