THE EXPRESSION OF GAL-BETA-1,4GLCNAC ALPHA-2,6 SIALYLTRANSFERASE AND ALPHA-2,6-LINKED SIALOGLYCOCONJUGATES IN HUMAN BRAIN-TUMORS

CMP-NeuAc: Gal beta 1,4GlcNAc alpha 2,6 sialyltransferase (alpha 2,6-S T) [EC 2.4.99.1] is developmentally regulated, shows a high degree of tissue specificity, and appears to play a role in oncogenic transforma tion and metastasis. In the present study, we have performed the first detailed analysis of the expression of alpha 2,6-ST and alpha 2,6-lin ked sialoglycoconjugates in human brain tumors. We used a polyclonal, monospecific anti-rat alpha 2,6-ST antibody and the alpha 2,6-linked s ialic acid-specific lectin, Sambucus nigra agglutinin (SNA) for histoc hemical studies, and a human alpha 2,6-ST-specific cDNA probe for Nort hern analysis. Meningiomas, chordomas and craniopharyngiomas frequentl y expressed alpha 2,6-ST and alpha 2,6-linked sialoglycoconjugates. Am ong the different meningioma subtypes, meningothelial meningiomas stai ned more strongly with both anti-alpha 2,6-ST antibody and SNA than th e fibroblastic and anaplastic meningiomas. On the other hand, all tumo rs of glial origin and medulloblastomas were virtually devoid of eithe r alpha 2,6-ST or alpha 2,6-linked sialoglycoconjugate expression. Mor eover, very weak to negligible expression of both alpha 2,6-ST and alp ha 2,6-linked sialoglycoconjugates was observed in brain metastases. I n conclusion, alpha 2,6-ST and alpha 2,6-linked sialoglycoconjugate ex pression is associated with non-neuroectodermal epithelial-like tumors .