The diagnostic significance of trophoblast cell-surface antigen-2 expression in benign and malignant thyroid lesions.

CONTEXT

Thyroid cancers are the most common malignancy of the endocrine system. Over-expression of trophoblast cell-surface antigen 2 (TROP-2) in various tumors has been found to correlate with poor prognosis and aggressive tumor behavior.

AIMS

The aim of this study was to evaluateTROP-2 expression in thyroid neoplasms.

SUBJECTS AND METHODS

This study contained 152 cases, including 48 follicular nodular disease (FND), 29 follicular adenoma (FA), 57 papillary thyroid carcinoma (PTC), 12 follicular thyroid carcinoma (FTC), 3 medullary thyroid carcinoma (MTC), 2 poorly differentiated thyroid carcinoma (PDTC) and 1 undifferentiated thyroid carcinoma (UDTC). TROP-2 expression was investigated via immunohistochemistry in sections prepared from paraffin blocks of the cases.

RESULTS

The cases comprised 32 (21%) males and 120 (79%) females with a mean age of 46.8 years (range, 15-85 years). TROP-2 expression was observed in 74.6% of the malignant lesions of the thyroid except for medullary carcinoma, poorly differentiated and undifferentiated thyroid carcinoma. Immunoreactivity was 3.4% in FA, 41.7% of cases with FTC and 81.8% in PTC follicular variant (PTC fv). The difference between FA/FTC and FA/PTC follicular variant were both significant (P < 0.005, P < 0.001, respectively). There was no difference between FTC/PTC fv (P = 0.089).

CONCLUSION

TROP-2 can be considered a useful marker for distinguishing PTC fv cases from follicular nodular disease and follicular adenoma cases because of its high sensitivity in the identification of papillary carcinomas of the thyroid.