[A model of orthotopic transplantation in mice using MBT-2]

We attempted to produce a malignant urinary bladder carcinoma in mice by transplanting MBT-2 cells. MBT-2 carcinoma about 3.0 x 10(3) cells/0.02 ml were successfully transplanted into the bladder wall with an incidence of 80% (20/25) after three experimental weeks. Inoculated tumor cells grew expansively into the bladder cavity from the bladder submucosa, and invaded the muscle layer. We observed that tumors caused gross hematuria and bilateral hydronephrosis. This malignant tumor model in which a tumor is implanted into its original organs seems to be useful for predicting clinical effectiveness in experimental cancer therapy.