Immunohistochemical investigation of axillary lymph nodes for micrometastases in patients with breast cancer using E29.

The axillary lymph nodes from 31 mammary carcinoma patients who had undergone radical mastectomy and were negative for metastases at routine histologic examination of hilar sections, were investigated with E29, an anti-epithelial monoclonal antibody, to detect the presence of neoplastic epithelial cells. In 4 of 433 lymph nodes examined (0.9%) this antibody revealed the presence of epithelial metastatic foci which had not been observed at routine histological examination or interpreted as histiocytes. The 4 lymph nodes belonged to 4 different patients.