Comparison between renal pelvic and ureteral tumors in muscle‐invasive upper tract urothelial carcinoma

Although renal pelvic and ureteral urothelial carcinoma share similarities in their origins, disparities on a genetic and clinical level make them divergent entities. Clinical information from the Surveillance, Epidemiology, and End Results (SEER) database was used to validate the characteristics and molecular subtypes using single‐center data, which were compared between the two types of muscle‐invasive tumors. Simultaneously, to expand the sample size for further verification, we explored a deep learning algorithm to correctly classify molecular subtypes from H&E histology slides. We suggested that the renal pelvic group might have a proclivity towards luminal and the ureter towards basal and P53‐like. Furthermore, we explore the heterogeneity of matrix and immune tumor microenvironment, and the ureteral group had more immune cell infiltration and higher stiffness. Collectively, these results showed that muscle‐invasive upper tract urothelial carcinoma exist in distinct properties of clinical characteristics, molecular subtype, and tumor microenvironment.