Autochthonous male urothelial carcinoma immune competent model: from induction to BCG transurethral treatment.

To describe a new animal model of autochthonous urothelial cancer (UC) accessible by transurethral catheter in males, from induction to treatment. Seven-week-old male Fischer 344 rats were used. The first 10 animals were used to overcome and standardize the technical challenges of safe transurethral catheterization of male rats. The remaining 14 animals underwent intravesical N-Methyl-Nitrosourea (MNU) instillation for UC induction, of which six were randomized to undergo intravesical BCG treatment. The stretched male rat urethra travels 35 mm in a tortuous "S" shaped trajectory with a 180° angle behind the pubic bone, safely traversed by a 20G 36" 0.8 mm epidural catheter in a stretched, straightened urethra inserted after anterior dilation of the penile urethra with a 24G IV catheter. Histopathologic analysis of the urinary bladder demonstrated Stage pT1, pTa, and pTis lesions in the 8 controls, all with increased cell proliferation by Ki-67 expression and no pT1 or pTis in the animals 6 treated with BCG. This pioneering study describes an autochthonous, effective, and accessible transurethral animal model of immune-competent UC in males, and may help with understanding of the biology, immunology, and treatment of UC, which predominates in males.