SLC2A1 and schwannoma: Glut-1 (glucose transporter isoform 1) as a member of a family of glucose transporters is normally expressed in perineurial cells, erythrocytes, germinal centers of lymphoid tissue, renal tubules, and some carcinomas.27 Glut-1 is very useful for differential diagnosis of perineuriomas from schwannomas and neurofibromas that are Glut-1 negative.