Use of monoclonal antibodies to human breast-tumor-associated antigens in fine-needle aspirate cytology.

Fine-needle aspiration cytology (FNAC) is currently used in evaluating the nature of breast nodules. In the present study we have examined whether monoclonal antibodies (MAbs) to breast-tumor-associated antigens (BTAA) can be employed in FNAC for the diagnosis of breast cancer. For this purpose we have used 2 murine MAbs recognizing 2 distinct BTAA expressed by breast tumors, irrespective of their histotype, in an indirect avidin-biotin immunohistochemical technique on aspirate smears. The results of this study show that, while benign lesions are consistently negative, tumor cells containing aspirates are reactive with at least one MAb in 95% of the cases. Thus, selected MAbs to BTAA may be a powerful diagnostic tool in conjunction with conventional cytology, and because of the objective interpretation of the immunohistochemical findings, FNAC of the breast can eventually be extended outside specialized institutions.