Galectin-3 expression and BRAF mutation in cases of cytologically suspicious papillary thyroid carcinoma

Background: Fine needle aspiration, which is known as the most accurate and cost-effective method for diagnosis of thyroid nodule, still may result in indeterminate cases that are pauci-cellular and show minor nuclear atypia, but most cases are associated with suspicion of papillary thyroid carcinoma (PTC). A B-type Raf kinase (BRAF) mutation was found in about half of PTCs and galectin-3 was expressed by malignant tumors, helping us to differentiate malignancies from benign lesions. Methods: Cases studied included histologically 44 confirmed PTC cases and 18 benign cases previously diagnosed as suspicious of PTC using cytologic examination. Cases were analyzed for galectin-3 expression by immunohistochemical staining and BRAF mutation by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with a new restriction enzyme. Results: All 44 cases of PTC and 8 of 18 benign controls expressed galectin-3. BRAF mutations were found in only 9 of the 44 PTC cases. Assessment of galectin-3 expression demonstrated high sensitivity but low specificity. Evaluation of BRAF mutation revealed high specificity and low sensitivity. Conclusions: This study suggests that the combined application of these two methods for PTC of suspicious cytology is complementary.