The significance of Galectin-3 expression in the immunocytochemical evaluation of thyroid fine needle aspiration cytology.

The aim of this study is to evaluate the significance of immunohistochemical expression of Galectin-3 in the differential diagnosis of benign and malignant thyroid nodules. We studied the fine needle aspiration specimens of 38 patients who had evaluated for nodular goiter and undergone a thyroid surgery between 2004-2005. Slides had been stained immunocytochemically with Galectin-3. The cytoplasmic staining of Galectin-3 was analyzed. Three cases of five follicular carcinomas had positive staining for Galectin-3, while two had not. Two cases with follicular adenomas were negative for Galectin-3. Five cases of six papillary carcinomas had positive staining for Galectin-3, while one case (the case with a papillary microcarcinoma) had not. The single cases with medullary and anaplastic carcinomas were negative for Galectin-3. None of the cases with a benign thyroid pathology had positive staining for Galectin-3. Galectin-3 immunocytochemical staining, had a sensitivity of 61.5%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 83.3% for thyroid malignancies. For the evaluation of follicular neoplasm, Galectin-3 immunocytochemical staining had a sensitivity of 60%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 50%. Galectin-3 expression in thyrocytes is a strong indicator of a malignant proliferative lesion especially for papillary and to an extent in follicular thyroid neoplasms. Galectin-3 could be used as a supplementary marker for cytological diagnosis.