ACTA ENDOCRINOLOGICA (BUC)

Aim. To evaluate the expression of Galectin-3, Fibronectin-1, Cytokeratin-19 and HBME1 in benign and malignant thyroid nodules and to assess their diagnostic value. Methods. Immunohistochemical analysis was performed on 59 surgically removed thyroid nodules, including 34 carcinomas (12 papillary, 2 tall cell variants, 3 lymph node metastases from papillary carcinoma, 5 follicular variants of papillary carcinoma (FVPTC), 3 anaplastic, 5 follicular and 4 Hürthle cell carcinomas), as well as 25 benign lesions (10 follicular adenomas, 4 Hürthle cell adenomas, 11 nodular goiters with surrounding normal thyroid tissue).3 expression in all malignant lesions except for one case of FVPTC and one follicular carcinoma. Normal thyrocytes and the majority of the benign lesions were negative for all markers. Statistical analysis of each protein confirmed that Galectin-3 was the most sensitive (94%), followed by Cytokeratin-19 (88%). Fibronectin-1 and HBME1 proved to be less sensitive (56% and 68%, respectively), but more specific (92% specificity for each of them). Coexpression of two or more proteins was restricted to carcinomas, while their concurrent absence was highly specific for benign lesions. Comparing the immunopositivity in follicular carcinoma versus adenoma we achieved 80% sensitivity for Galectin-3 and 100% specificity for HBME1. For distinguishing the Hürthle cell lesions, Fibronectin-1 turned out to be more sensitive than Galectin-3 and Cytokeratin- 19. Conclusion. Our findings suggest that immunohistochemical panel consisting of Galectin-3, Cytokeratin-19, HBME1 and Fibronectin-1 might contribute to differential diagnosis between malignant and benign thyroid nodules, including those with follicular architecture.