DIFFERENTIATION OF THYROID NEOPLASMS BY EVALUATING EPITHELIAL MEMBRANE ANTIGEN, LEU-7 ANTIGEN, EPIDERMAL GROWTH-FACTOR RECEPTOR, AND DNA CONTENT

The expression of epithelial membrane antigen (EMA), Leu-7 antigen, epidermal growth factor receptor (EGFr), and deoxyribonucleic acid (DNA) content in 40 thyroid nodules was investigated to identify those factors that might differentiate these lesions or correlate to their prognosis. There were 22 carcinomas (16 papillary, 4 follicular; 1 anaplastic, 1 medullary) and 18 benign lesions prospectively obtained between 1989 and 1993. Patients' charts were reviewed to establish a database of known clinical prognostic indicators. Expression of EMA and Leu-7 was significant in malignant lesions when compared to benign lesions (P < 0.02 and P < 0.001). EMA was expressed significantly more frequently by follicular carcinomas than by follicular adenomas (P < 0.03). Leu-7 antigen was expressed by all papillary carcinomas. Neither of these antigens showed any association with known clinical prognostic indicators. EGFr expression neither differentiated benign from malignant lesions nor correlated with prognostic factors. The presence of aneuploidy correlated with poor tumor differentiation (P < 0.02), but did not distinguish benign from malignant lesions. These results suggest that EMA expression may be useful for confirming malignancy in follicular neoplasms and that the expression of Leu-7 antigen can assist in distinguishing papillary carcinoma from benign lesions with pseudopapillae.