Enhanced cytologic detection of early stage mouse bladder tumor following induction of uroepithelial cell shedding.

Previous studies from our laboratory have shown that some Escherichia coli endotoxins are capable of inducing massive normal urothelial cell shedding. In the present study we investigated whether endotoxin-induced shedding improves cytologic detection of early stage mouse bladder cancer. Mouse bladder tumor (MBT-2) cells were implanted intravesically in the submucosa of C3H female mice. Ten to 21 days later the bladders were irrigated with saline followed by instillation of endotoxin. The bladder contents of each mouse were aspirated and examined cytologically together with the bladder wash specimen. Shedding of epithelial cells was observed in only 32% of the saline irrigated specimens compared with 93% after endotoxin instillation (p < 0.00001). Analysis showed an overall accuracy rate of 39% after saline barbotage versus 78% following endotoxin administration (p < 0.00001). These results indicate that intravesical instillation of specific bacterial endotoxin significantly increases the extent of cytologic detection of early stage superficial bladder cancer.