Mouse orthotopic models for bladder cancer research

Bladder cancer is a common malignancy in the urinary tract. Despite different therapeutic options, recurrence and progression of urothelial carcinoma after treatment is not uncommon. Novel therapeutic options of bladder cancer are urgently needed. The preclinical evaluation of new treatments requires an animal tumour model that mimics the human counterpart. To date, various animal orthotopic bladder cancer models have been described, but the reported rate of tumour 'take' is 30-100%. The establishment of reliable and reproducible animal models remains an ongoing challenge. We review different kinds of mouse models of orthotopic bladder cancer used in urothelial cancer studies, the methods of implantation, and the reported rate of tumour take. Significant progress has been made recently in noninvasive small animal-imaging in tumour models. It is now possible for researchers to investigate the effects of studied agents by monitoring of in vivo tumour growth directly and noninvasively, as well as measuring a wide range of tumour-related variables in small animals. We summarize the recent development in small-animal imaging for tumour detection and quantification.