Immunohistochemical Expression of HBME-1, E-cadherin, and CD56 in the Differential Diagnosis of Thyroid Nodules

Background and Objective. Distinction between benign and malignant thyroid tumors is essential for proper clinical management. The aim of this study was to evaluate the diagnostic potential of a set of 3 molecular markers in the differential diagnosis of thyroid tumors.
Material and Methods. Immunohistochemistry for HBME-1, E-cadherin (E-CAD), and CD56 was carried out in 36 follicular adenomas, 77 colloid goiters, 36 papillary thyroid carcinomas, and 14 follicular carcinomas. Sixty-eight thyroid fine needle aspiration (FNA) cases confirmed by subsequent surgical resection specimens were selected. Immunocytochemistry for HBME-1, E-CAD, and CD56 was performed in these cases, including 25 papillary thyroid carcinomas, 1 follicular carcinoma, 22 follicular adenomas, and 20 colloid goiters.
Results. PTC was characterized by a decreased expression of E-CAD and CD56 contrary to the surrounding benign thyroid tissues. There was no HBME-1 expression in benign thyroid tissues, but it was high in papillary thyroid carcinomas and weak in follicular adenomas. The expression of E-CAD and CD56 was significantly higher in follicular adenomas than in the surrounding thyroid tissues. Analyzing the FNA material, HBME-1 expression was documented in 96% of papillary thyroid carcinomas, but there was no expression in the benign lesions. E-CAD and CD56 expression was significantly weakened in papillary thyroid carcinomas, but enhanced in follicular adenomas.
Conclusions. HBME-1 was found only in malignant lesions and can be considered the most sensitive, specific single marker in papillary thyroid carcinomas. CD56 and E-CAD can assist in the decision-making on the benign and malignant nature of the nodule. Immunocytochemistry is of value as an ancillary test to enhance the diagnostic accuracy of thyroid FNA samples.