Distribution of epithelial membrane antigen in normal and abnormal endometrial tissue.

The distribution of epithelial membrane antigen (EMA) on normal and abnormal endometrial tissue was studied as a method for distinguishing atypical hyperplasia from adenocarcinoma. Histological sections from 47 patients (nine adenocarcinoma, nine atypical hyperplasia, nine cystic hyperplasia, 19 normal endometrium and one sarcoma) were studied with an immunocytochemical alkaline phosphatase technique that demonstrated EMA. At a dilution of 1:1000 the majority of normal tissue was negative whereas all the abnormal tissue stained positively. At a slightly higher dilution all adenocarcinomas expressed the antigen although only a few of the hyperplastic lesions (16%) stained with the antibody. The value of this approach for automated screening is discussed.