Data mining TCGA expression data for urothelial and prostate lineage markers, this study establishes that in descending order of importance, genes for uroplakin II, S100P, GATA3 and thrombomodulin are the most important urothelial lineage markers to distinguish a carcinoma as bladder urothelial carcinoma from prostate adenocarcinoma. The gene discussed is THBD; the disease is bladder transitional cell carcinoma.