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N-acetylglucosaminyltransferase V (GnT-V) is a key enzyme in formation of b1-6 branching asparagine-linked oligosaccharide. Recent reports have suggested that GnT-V expression is involved in the early phase of tumorigenesis. However, the expression of GnT-V in head and neck cancer has not been demonstrated yet. We examined the expression of GnT-V protein and mRNAs in human tongue SCC cases and its relationship to clinicopathological characteristics. The protein expression of GnT-V was studied by immunohistochemistry in biopsy materials of 40 SCC cases and 4 premalignant lesions. In parallel, GnT-V mRNA expression was examined by real time-PCR and compared with the expression levels of normal tongue tissues. In immunohistochemistry, 26 of the 40 cases of SCC showed specific expression of GnT-V in tongue SCC tissues. In contrast, none of the 4 premalignant lesions showed positive signals for GnT-V. GnT-V expression in SCC was positively correlated with the T factor, tumor invasion pattern, histological differentiation, and cervical lymph node metastasis . Furthermore, among the early lesions of SCC in clinical stages 0, I and II, the subsequent metastatic rate was significantly higher in SCCs that were GnT-V positive than in SCCs that were GnT-V negative. All SCC cases examined showed increased GnT-V mRNA levels in comparison to normal tongue tissues by real-time PCR. Contrastively, GnT-V expression was not enhanced in premalignant lesions.These findings suggest that GnT-V expression is closely correlated with tongue SCC progression and the malignant phenotype with increased invasive and metastatic abilities.

[Proc Amer Assoc Cancer Res, Volume 47, 2006]