OBJECTIVETo investigate the difference of galectin-3 and CD44v6 expression between benign and malignant thyroid nodules, and to evaluate their clinical value in distinguishing thyroid cancer from benign thyroid nodules.

METHODSThe expression of galectin-3 and CD44v6 was immunohistochemically detected by the ABC method in 143 benign and malignant thyroid nodule samples.

RESULTSExpression of these two markers in benign thyroid nodules: galectin-3 was negative in 10 cases of para-cancer normal tissue and 14 cases of benign nodules found in the other benign thyroid disease. It was weakly positive in 4 of 52 nodular goiter (7.7%). Also it was weakly positive in 2 of 22 follicular adenomas (9.1%). But all three eosinophilic follicular adenomas were diffusely or focally positive for galectin-3. CD44v6 was negative in 10 cases of para-cancer normal tissue, but positive in 4 of 14 nodular lesions found in benign thyroid diseases (28.6%). It was also positive in 16 of 52 nodular goiters (30.8%), and weakly positive in 7 of 22 follicular adenomas (31.8%). The two markers in malignant lesions: galectin-3 was positive in 50 of 52 thyroid adenocarcinoma (96.2%), CD44v6 was positive in 42 of 52 thyroid adenocarcinoma (80.8%). The positive rate of galectin-3 and CD44v6 expression in thyroid cancer was significantly higher than that in benign thyroid nodule and normal tissue (P < 0.001). The sensitivity, specificity and accuracy of galectin-3 combined with CD44v6 in differentiating benign from malignant thyroid nodule were 80.8%, 93.4%, 88.8%; they were 96.2%, 90.1%, 92.3% for Galectin-3 alone.

CONCLUSIONThe immunohistochemical expression of galectin-3 and CD44v6 by the ABC method is significantly higher in thyroid cancers than in benign thyroid nodules, especially galectin-3 in thyrocyte being helpful in differentiating benign thyroid nodule from thyroid cancer.