Type 2 chain glycosylation in thyroid carcinomas

Abstract

Alterations of cell-surface carbohydrates are important for the metastatic behaviour of human carcinomas. Follicular and papillary thyroid carcinomas clinically show a very different metastatic pattern and represent a good model for studies of the metastatic process. We examined the expression of various Lex-related carbohydrates in 30 primary papillary, 20 primary follicular and 15 primary anaplastic thyroid carcinomas by means of immunohistochemistry. Six metastases from papillary and five from follicular carcinomas were also examined. Morphologically normal thyroid epithelium did not express any of the type 2 carbohydrates. Papillary carcinomas were immunoreactive for several type 2 carbohydrates, including sialyl-Lewis X, in contrast to follicular and anaplastic carcinomas. The metastases showed no significant differences in expression of carbohydrates compared with the primary tumours. We hypothesize that the up-regulation of sialyl-Lewis X and some other related carbohydrates in papillary carcinomas is of importance for the clinical behaviour of these tumours.