Immunohistochemical expression of glucose transporter-1 in human penile proliferative lesions

Glucose transporters (GLUTs) are a family of membrane proteins responsible for the transport of glucose across cellular membranes. In terms of their mRNA levels, they have been reported to be expressed in some human tumours. However, the immunohistochemical localization of GLUTs in human urogenital lesions has rarely been studied. This study was performed to evaluate the expression of GLUT1 in penile proliferative lesions (18 cases of penile carcinoma and 13 cases of condyloma acuminatum). Using an isoform-specific anti-GLUT1 antibody, formalin-fixed paraffin-embedded sections were stained by the avidin-biotin complex method. In all cases of penile carcinoma, GLUT1 staining was diffusely recognized on the cell membrane of the carcinoma cells in the mainly infiltrating areas. However, the inner areas of the tumour were more weakly and focally stained. The intensity of staining for the penile carcinoma (staining score = 2.8 +/- 0.6) was stronger than that for condyloma acuminatum and that for adjacent non-proliferative areas. All cases of condyloma acuminatum showed a diffuse staining on the cell membrane in the basal and intermediate layers (staining score = 2.4 +/- 0.5). Non-proliferative (histologically normal) glans areas adjacent to the above lesions expressed the weakest GLUT1 staining only in the stratum basale (staining score = 1.8 +/- 0.5). These three areas showed significantly different staining scores from each other (p < 0.01). In conclusion, GLUT1 is expressed dominantly in penile proliferative lesions, especially in infiltrating areas of penile carcinoma.