TP53 and transitional cell carcinoma: Histological analysis confirmed that the generated tumors were in most cases urothelial cell carcinomas, ranging from 40% (p53 + Cmyc) up to 100% of experimental animals (p53 + Kras + Cmyc) and of those tumors shown to be urothelial cell carcinomas, we detected the primary tumor in the bladder in almost all cases (Supp.