The results of our study confirm a diagnostic utility of Upk1a and Upk1b IHC for the distinction of urothelial carcinomas from other tumor entities and also suggest a prognostic utility of Upk1a/Upk1b measurement as a part of a panel that distinguishes a “luminal” urothelial cancer phenotype. Here, UPK1A is linked to urothelial carcinoma.