Utility of galectin 3 expression in thyroid aspirates as a diagnostic marker in differentiating benign from malignant thyroid neoplasms.

Galectin-3 is a 31kD beta-galactoside binding lectin, which is known to be expressed in various neoplasms including thyroid tumors. This study was conducted to study the role of galectin-3 in differentiating benign from malignant thyroid nodules onfine needle aspirates (FNAC). Galectin-3 immuocytochemistry was performed in 70 cases with adequate smears. The cytology diagnosis of these cases was: papillary carcinoma (25), follicular neoplasm (16), adenomatous goiter (20), hyperplastic nodule (5), medullary carcinoma (5) and anaplastic carcinoma (1). Galectin-3 positivity was seen in 80% of papillary carcinomas, 37.5% offollicular neoplasms and in 60% of benign nodules. The single case of anaplastic carcinoma was positive but all the cases of medullary carcinoma were negativefor galectin-3. Three of thefollicular neoplasms that were diagnosed on histology as carcinoma were positive on cytology and one case offollicular adenoma was also positive. Our study shows that galectin-3 is strongly expressed in smears of papillary carcinoma. However, since it is also expressed in a variety of benign lesions, its role as a pre-surgical markerfor differentiating benignfrom malignant thyroid nodules is limited.