Cytological and histological diagnoses of recurrent thyroid carcinoma with monoclonal antibody JT-95, which can detect modified fibronectin.

Although fine needle aspiration (FNA) cytology has increasingly gained importance as a tool in thyroid diagnosis over the recent years, up to 20% of thyroid carcinomas, in particular follicular tumors and follicular variant tumors, are inconclusive by FNA. The monoclonal antibody (MoAb) JT-95 detects the modified fibronectin, expressed in most thyroid carcinomas. Consequently, it has been applied to FNA and tissue section specimens obtained from thyroid tumors during surgery. For FNA specimens of 57 thyroid tumors followed-up for more than 10 years postoperatively and stained with both the Papanicolaou and the immunoperoxidase technique using MoAb JT-95, we retrospectively compared the sensitivity, specificity, and diagnostic accuracy of the two procedures. Histological specimens stained with HE and investigated by JT-95 were also re-evaluated. The pathological results of aspirated specimens, after a change in diagnosis following recurrence, revealed that 43 of 47 malignant lesions were positive, while nine of 10 benign tumors remained unreactive using MoAb JT-95. Sensitivity was 91.4%, specificity 90.0%, and diagnostic accuracy 91.2% by JT-95 cytology. By contrast, sensitivity ascertained by the Papanicolaou technique was 78.1%, specificity 100%, and accuracy 82.4%. Of the six examples that recurred during the 10-12-year follow-up period, tissue sections of all six and aspirated materials of five of the six were stained by JT-95.