Glucose Transporter-1 Expression in Urothelial Papilloma of the Bladder

INTRODUCTION: Urothelial papilloma should be distinguished from low-grade urothelial carcinoma. We report our experience with glucose transporter-1 (Glut-1) expression in urothelial papilloma. MATERIALS AND METHODS: From January 1987 to December 2002, 32 patients with papilloma were diagnosed. Glut-1 protein expression was studied in 32 cases of papilloma and 30 cases of carcinoma. Clinical information was obtained by chart review. RESULTS: Mean age was 54.7 years, and the solitary lesion was 78.1%. No case of bladder papilloma expressed Glut-1 protein even in cases of recurrent papilloma. However, 67% of urothelial carcinoma specimens were stained for Glut-1 protein. Two patients developed recurrent papilloma (6.2%), 1 of whom (3.1%) developed an urothelial carcinoma 4 years after diagnosis of papilloma. CONCLUSIONS: The study showed that papilloma does not express the Glut-1 protein in contrast to urothelial carcinoma. This distinctive expression pattern of Glut-1 will possibly contribute to differentiate urothelial papilloma from low-grade urothelial carcinoma.