Immunohistochemical expression of monoclonal antibodies (epi-1 and myo-1) derived from human breast cancer against rat mammary tumors.

Immunohistochemical expression of monoclonal antibodies epi-1 and myo-1 derived from human breast cancer cell line (HBC-4W) was examined for DMBA-induced rat mammary tumors. Antibody epi-1 reacted with luminal epithelial cells while antibody myo-1 reacted with myoepithelial cells of the mammary glands in rats, respectively. The reactions with both antibodies were markedly visible, in particular, in the normal mammary gland, tumor-like lesions and benign epithelial mammary tumors in rats, which showed clear two-cell-type structures. Among malignant mammary tumors, adenocarcinoma was strongly positive with antibodies epi-1 and myo-1. However, squamous cell carcinoma and adenoacanthoma mainly reacted with antibody epi-1. On the other hand, the intercellular matrices of pleomorphic cell sarcoma and stromal areas of the normal mammary gland or epithelial tumors were positive with antibody myo-1.