Epithelial membrane antigen in cells from the uterine cervix: immunocytochemical staining of cervical smears.

Smears made from cervical scrapes have been stained immunocytochemically for epithelial membrane antigen using a polyclonal antiserum and two monoclonal antibodies. With the polyclonal antiserum malignant cells and those showing dysplasia consistently expressed the antigen. Normal cells were generally negative, with the exception of some metaplastic cells. The monoclonal antibodies, although they stained the abnormal cells less consistently, gave the same pattern of staining. All three antibodies showed considerable heterogeneity in the intensity of stain. This appears to be a general feature of the expression of this type of epitope in epithelial cells. While the results confirm that an immunohistochemical stain might have potential application for improved diagnostic methods, the staining of metaplastic cells with the presently available antibodies limits the usefulness of an antiserum to epithelial membrane antigen.