TACSTD2 and Gastric Metaplasia: Further data demonstrating that TROP2 is upregulated in the early stages of tumorigenesis were provided by Riera and colleagues in a study using mouse models of gastric tumorigenesis and human biopsy samples, which showed that TROP2 is a potential biomarker for the transition from gastric metaplasia to dysplasia and adenocarcinoma of the stomach [90].