Galectin-3 detection in the thyroid gland and follicle cell tumors of the thyroid. A study of its possible role in preoperative differential diagnosis

Galectin-3 belongs to a group of endogenous lectins with an affinity to gly coconjugates containing beta -galactoside residues. It has been detected in numerous tissues and studied in connection with tumor growth, dedifferenti ation, and metastasis. Only few studies have dealt with galectin-3 detectio n in tumors of the thyroid gland and with its possible role for differentia l diagnosis. We studied 118 cases of thyroid gland tumors with a monoclonal antibody against galectin-3; we compared the preparations by a semiquantit ative score to determine differences in expression. Normal thyroid gland ti ssue, goiter tissue, and tissue with functional enhancement were largely ne gative for galectin-3. Adenomas with a typical cytological pattern were pre dominantly negative, but a focal positive reaction in single cells and cell groups or follicles was possible. Almost all papillary carcinomas showed a distinct galectin-3 expression. While findings in follicular carcinomas an d oxyphilic adenomas and carcinomas were very uneven, with both positive an d negative tumors, the galectin-3 reaction can be helpful in recognizing fo llicular variants of the papillary carcinoma. Investigation of the biologic al significance of tumors should always be cautious and consider known hist ological criteria for malignancy.