Trop-2 and Ephrin B2 expression in urothelial carcinoma with divergent differentiation and aggressive urothelial carcinoma subtypes.

Objectives: Urothelial carcinomas (UCs) encompass a heterogeneous group of tumors. Several histopathologic features are associated with poor clinical outcomes and limited treatment options. With new rising therapeutic modalities, we aimed to determine the pattern of expression of Trop-2 and ephrin B2 in UC with aggressive subtype histology and/or divergent differentiation (SH/DD).

Methods: We performed a retrospective analysis of 113 UC samples with SH/DD at our institution from 2011 to 2021. Immunohistochemical staining for Trop-2 and ephrin B2 expression was performed on all cases. Expression was determined by the percentage of samples with a moderate or strong H-score.

Results: Our results show Trop-2 expression was the highest in squamous cell carcinoma and UC with squamous differentiation, adenocarcinoma and UC with glandular differentiation, and plasmacytoid subtype, while ephrin B2 expression was highest in adenocarcinoma, UC with glandular differentiation, and small cell carcinoma.

Conclusions: Expression of Trop-2 and ephrin B2 may demonstrate therapeutic possibilities for patients with SH/DD, who usually have limited treatment options, particularly in small cell carcinoma, in which few targets have been identified. Clinical trials to investigate the efficacy of these novel treatments are warranted.