Background: Treatment options for advanced urothelial carcinoma (aUC) rapidly evolved in recent years. Besides immunomodulative therapeutic options like anti-PD-(L)1 inhibitors and inhibitors targeting FGFR alterations, two new antibody-drug conjugates (ADC), sacituzumab govitecan (SG) and enfortumab vedotin (EV), have been approved for treatment. However, little is known about associations of specific aUC properties and the surface target expression of TROP2 and NECTIN-4. This study characterizes associations of TACSTD2/TROP2 and NECTIN-4/NECTIN-4 gene and protein expression with morphomolecular and clinico-pathological characteristics of aUC in two large independent cohorts. Methods: The TCGA BLCA (n=405) and the CCC-EMN (n=247) cohorts were retrospectively analyzed. Expression of mRNA and protein for TACSTD2/TROP2 and NECTIN-4/NECTIN-4 was measured and correlated with clinico-pathological characteristics, molecular subtypes, FGFR3 alterations and PD-L1 expression. Results:TACSTD2/TROP2 and NECTIN-4/NECTIN-4are highly expressed at protein and transcript level in aUC, and their expression status did not correlate with patient survival in two independent cohorts. NECTIN-4/NECTIN-4 expression was higher in luminal tumors and reduced in squamous aUCs. NECTIN-4 was negative in 10.6% of samples, and 18.4% of samples had low expression (H-Score < 15). TROP2 negativity rate amounted to 6.5%. TACSTD2 and NECTIN-4 expression was reduced in neuroendocrine-like and/or protein-based double negative tumors. TROP2 and NECTIN-4 negative tumors (protein level) included one sarcomatoid and four neuroendocrine aUC. FGFR3 alterations and PD-L1 expression on tumor and immune cells did not associate with TROP2 or NECTIN-4 expression. Conclusions:TACSTD2/TROP2 and NECTIN-4/NECTIN-4 are widely expressed in aUC, independent of FGFR3 alterations or PD-L1 expression. Expression loss is associated with aggressive morphomolecular aUC subtypes, i.e. neuroendocrine(-like) and sarcomatoid aUC. TROP2 and NECTIN-4 are widely expressed in aUC thus representing suitable targets for novel ADC treatment for the majority of aUC patients.