Expression of UDP-N-acetyl-D-galactosamine: Polypeptide N-acetylgalactosaminyltransferase-6 in Gastric Mucosa, Intestinal Metaplasia, and Gastric Carcinoma

Aberrant mucin O-glycosylation is often observed in cancer and is characterized by the expression of immature simple mucin-type carbohydrate antigens. UDP-N-acetyl-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase-6 (ppGalNAc-T6) is one of the enzymes responsible for the initial step in O-glycosylation. This study evaluated the expression of ppGalNAc-T6 in human gastric mucosa, intestinal metaplasia, and gastric carcinomas. Our results showed that ppGalNAc-T6 is expressed in normal gastric mucosa and in intestinal metaplasia. A heterogeneous expression and staining pattern for this enzyme was observed in gastric carcinomas. ppGalNAc-T6 was expressed in 79% of the cases, and its expression level was associated with the presence of venous invasion. Our results provide evidence that ppGalNAc-T6 is an IHC marker associated with venous invasion in gastric carcinoma and may contribute to the understanding of the molecular mechanisms that underlie aberrant glycosylation in gastric carcinogenesis and in gastric carcinoma. (J Histochem Cytochem 57:79-86, 2009)