POTENTIAL USE OF MONOCLONAL-ANTIBODIES IN THE DIAGNOSTIC DISTINCTION OF GYNECOMASTIA FROM BREAST-CARCINOMA IN MEN

Immunohistochemical (IHC) assays using the monoclonal antibodies (MoAbs) B72.3 and B6.2, recognizing two distinct and independently expressed breast tumor-associated antigens (BTAAs), recently have been shown to significantly improve the accuracy of cytodiagnosis of breast nodules by fine-needle aspiration (FNA). To evaluate whether the same method may be useful diagnostically in distinguishing gynecomastia from breast cancer in men, a retrospective avidin-biotin immunoperoxidase assay study was performed on 50 cases of gynecomastia and 30 cases of breast carcinoma in men, using a panel of five MoAbs known to recognize different BTAAs. The results of this study demonstrated that MoAbs B1.1, HMFG2, and MBr1 displayed a strong reactivity with gynecomastia and carcinoma, but MoAbs B72.3 and B6.2 separated benign and malignant lesions in a high percentage of cases. When used in combination, the latter two reagents reacted with 96% of the carcinomas that were analyzed but labeled only 67% of gynecomastia cases. Thus, the conjoint use of these two reagents may enhance the use of FNA biopsy as a valuable tool in the presurgical diagnosis of breast nodules in men.