ASSESSMENT OF PERINEURAL INVASION BY GLUT-1 IMMUNOHISTOCHEMISTRY

Glucose transporter protein I (GLUT-1) is expressed in endothelial cel ls with barrier functions, like blood-brain barrier, including intrane ural vessels in peripheral nerves and perineurium. Its presence allows for unidirectional selective transport of glucose, while maintaining restriction of other molecules. We studied the expression of GLUT-1 in peripheral nerves within and surrounding tumors of different origin ( colon, breast, prostate) to assess the value of GLUT-I immunoreactivit y in the diagnosis of perineural invasion of malignant tumors. Maligna nt neoplasms of prostate, colon, and breast were stained with antibody against GLUT-1 and the S-100 protein. Prominent expression of GLUT-I was seen in the perineurium of peripheral nerves, In cases of perineur al invasion, tumor cells were seen both under the perineural sheath an d between layers of the perineurium. True perineural invasion could be clearly discerned from noninvasive close neural proximity of tumor ce lls by GLUT-I but not by S-100. We conclude that immunohistochemical s taining for GLUT-1 is superior to S-100 in the assessment of perineura l invasion.