Behavior of epithelial differentiation antigens (carcinoembryonic antigen, epithelial membrane antigen, keratin and cytokeratin) in transitional cell carcinomas of the bladder.

Results of an immunohistochemical study in normal urothelium and transitional cell carcinomas of the bladder are presented. Paraffin-embedded material was confronted with immunoantisera against carcinoembryonic antigen (CEA), keratin (K), cytokeratin (CK) and epithelial membrane antigen (EMA). Immunohistochemical findings confirm the changes in reactivity of dysplastic urothelium and carcinoma in situ for CEA, CK and EMA, in comparison with normal urothelium. Statistically significant differences were also found, depending upon tumor stage, in staining of transitional cell carcinomas for K and CK. Expression of CK correlated with the tumor differentiation grade: normal urothelium and well-differentiated carcinomas showed a specific pattern of immunostaining for the basal cells, this pattern being lost in poorly differentiated carcinomas.