The expression of Galβ1,4GlcNAc α2,6 sialyltransferase and α2,6-linked sialoglycoconjugates in human brain tumors

CMP-NeuAc: Galβ1,4GlcNAc α2,6 sialyltransferase (α2,6-ST) [EC 2.4.99.1] is developmentally regulated, shows a high degree of tissue specificity, and appears to play a role in oncogenic transformation and metastasis. In the present study, we have performed the first detailed analysis of the expression of α2,6-ST and α2,6-linked sialoglycoconjugates in human brain tumors. We used a polyclonal, monospecific anti-rat α2,6-ST antibody and the α2,6-linked sialic acid-specific lectin, Sambucus nigra agglutinin (SNA) for histochemical studies, and a human α2,6-ST-specific cDNA probe for Northern analysis. Meningiomas, chordomas and craniopharyngiomas frequently expressed α2,6-ST and α2,6-linked sialoglycoconjugates. Among the different meningioma subtypes, meningothelial meningiomas stained more strongly with both anti-α2,6-ST antibody and SNA than the fibroblastic and anaplastic meningiomas. On the other hand, all tumors of glial origin and medulloblastomas were virtually devoid of either α2,6-ST or α2,6-linked sialoglycoconjugate expression. Moreover, very weak to negligible expression of both α2,6-ST and α2,6-linked sialoglycoconjugates was observed in brain metastases. In conclusion, α2,6-ST and α2,6-linked sialoglycoconjugate expression is associated with non-neuroectodermal epithelial-like tumors.