The investigation of galectin-3 in diseases of the thyroid gland

Objective: Malignant tumors of the thyroid gland exhibit a variety of histopathologies and clinical behavior. Immune markers are gaining more and more importance in diagnostic pathology, especially in the differential diagnostics and in the grading of thyroid gland tumors. Design: The authors investigated the immunohistochemical reaction of galectin-3 (gal3) in patients with various thyroid gland diseases. They tested the diagnostic value of gal3 in determining the benign or malignant nature of various lesions, especially in lesions of follicular origin, because previous results have indicated nearly 100% specificity and sensitivity in this regard. Methods: Gal3 immunoperoxidase reaction was carried out on 91 sections of thyroid gland samples fixed in formalin and embedded in paraffin. Results: While gal3 expressed itself strongly and diffusely in papillary carcinomas (19 of 20 cases). in other malignant lesions it showed weaker, focal or variable positivity. Focal positivity was found in four of 19 follicular adenomas. and negativity was found in three of 10 follicular carcinomas. In all cases of inflammation a focal positivity was observed (eight of eight cases). All nodular goiter and normal thyroid tissue were negative (25 of 25 cases). Conclusions: Based on our results, the gal3 immunohistochemical reaction seems to be reliable in the diagnosis of papillary carcinomas. However. in the case of solitary thyroid nodules and follicular lesions, although it is still a useful supplementary marker, it is not of absolute value (as stated in previous studies) in determining whether a tumor is benign or malignant.