Differences in the O-glycosylation patterns between lung squamous cell carcinoma and adenocarcinoma.

Mucins are highly O-glycosylated proteins synthesized by epithelial cells, and their glycosylation patterns can be altered during neoplastic transformation. The 2 types of non-small cell lung cancer (NSCLC) display a similar pattern of mucin gene expression but different reactivity to periodic acid-Schiff diastase, suggesting that a higher number of carbohydrate chains are present in adenocarcinomas. We compared the expression of core (Tn, sialyl-Tn, T) and terminal fucosylated and sialylated (Lewis antigens) carbohydrate structures in lung tumors. Specific antibodies were usedfor immunohistochemical and Western blot assays. Results indicated that core and terminal structures are detected more frequently in adenocarcinoma than in squamous cell carcinoma, except Lewis y, which is expressed strongly in both types of NSCLC. These data suggest that in squamous cell carcinoma and adenocarcinoma, different sets of glycosyltransferases must be expressed and that different posttranslational modifications of the mucin genes can take place in these 2 tumor types.