Immunohistochemical localization of the glucose transporter GLUT1 in choroid plexus papillomas.

Normal chroid plexus tissue and five choroid plexus papillomas were examined with antibody specific for the glucose transporter GLUT1, one isoform of facilitated-diffusion glucose transporters, using the avidin-biotin-peroxidase complex (ABC) technique. GLUT1 in normal choroid plexus was localized at the basolateral plasma membrane of almost all epithelial cells. In three of five tumors, GLUT1 immunoreactivity was observed. A positive reaction was demonstrated at the plasma membrane of tumor cells. The number of GLUT1-positive cells was, however, much smaller than that of the normal choroid plexus. Our results suggest that GLUT1 expression in the choroid plexus is restrained during the course of transformation and that choroid plexus papilloma is composed of various differentiation tumor cells.