Potential value of antisera to epithelial membrane antigen in detecting early invasion in transitional cell carcinoma.

The distribution of epithelial membrane antigen in human transitional epithelium using immunocytochemical techniques was investigated. In normal urothelium the antigen is restricted to the luminal surface and superficial cell cytoplasm. During neoplastic progression cytoplasmic staining of intermediate and basal cells is seen. In certain circumstances staining is seen at the interface between the stroma and tumour. The latter appearance correlates with the presence of invasion as assessed by conventional histology and may help to identify early invasion in difficult cases.