RESUMO
BACKGROUND AND OBJECTIVES: Galectin-3 is a beta-galactoside binding protein that has been reported to be implicated in numerous biologic and pathologic functions including cell growth, cell adhesion, inflammation, neoplastic transformation, and apoptosis. Most previous studies in thyroid tissue have found galectin-3 expression to be a feature of malignant and not of benign or normal tissue. The aim of this study was to investigate the expression of galectin-3 in 57 thyroid lesions, to assess its potential as a marker in the diagnosis and classification of thyroid malignancy. SUBJECTS AND METHOD: The followings were studied: 19 cases of papillary carcinomas, 8 of follicular carcinomas, one anaplastic carcinoma, one medullary carcinoma, 16 follicular adenomas, and 12 nodular hyperplasia. Formalin-fixed paraffin-embedded thyroid tissues were stained immunohistochemically for galectin-3. RESULTS: Galectin-3 expression was found in all cases, however, it was strong in papillary carcinomas than in follicular carcinomas or adenomas. In nodular hyperplasia, galectin-3 expression was very weak and focal. A significant difference was not found in the expression of galectin-3 between follicular carcinomas and follicular adenomas. CONCLUSION: Galectin-3 is a reliable marker of papillary carcinoma but not useful in identifying follicular carcinoma.