CBX7 Expression in Oncocytic Thyroid Neoplastic Lesions (Hurthle Cell Adenomas and Carcinomas).

BACKGROUND: Previous analysis of CBX7 expression in a large number of thyroid adenoma and carcinoma samples revealed a progressive reduction of CBX7 levels that was well related with the malignant grade of thyroid neoplasias. Hürthle cell tumors are unusual thyroid neoplasms characterized by the presence of particular cells called oncocytes. OBJECTIVES: In order to develop new tools for a more accurate diagnosis of Hürthle cell tumors of the thyroid, we evaluated CBX7 protein levels to verify the possible presence of an expression signature. METHODS: CBX7 expression was evaluated by immunohistochemistry in a panel of thyroid tissue sections including normal thyroids, goiters, follicular adenomas and oncocytic lesions. RESULTS: CBX7 expression was low or null in 68% of Hürthle adenomas, whereas it was comparable to normal thyroid tissue in Hürthle hyperplasias and follicular adenomas. CONCLUSIONS: Reduced expression of CBX7 suggests a more aggressive identity of Hürthle adenomas with respect to non-Hürthle ones.