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, ep idermal growth factor receptor (EGFr), and deoxyribonucleic acid (DNA) content in 40 thyroid nodules was investigated to identify those fact ors that might differentiate these lesions or correlate to their progn osis. There were 22 carcinomas (16 papillary, 4 follicular; 1 anaplast ic, 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 w as significant in malignant lesions when compared to benign lesions (P < 0.02 and P < 0.001). EMA was expressed significantly more frequentl y 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 indica tors. EGFr expression neither differentiated benign from malignant les ions nor correlated with prognostic factors. The presence of aneuploid y correlated with poor tumor differentiation (P < 0.02), but did not d istinguish benign from malignant lesions. These results suggest that E MA expression may be useful for confirming malignancy in follicular ne oplasms and that the expression of Leu-7 antigen can assist in disting uishing papillary carcinoma from benign lesions with pseudopapillae.