RESUMEN
Immunohistochemical expression of keratin proteins and epithelial membrane antigen [EMA] were studied in 23 specimens of bilharzial associated human bladder cancer, using an indirect immunoperoxidase method on formalin fixed paraffin embedded sections.Expression of both tumour markers was detected in vast majority of differentiated carcinomas with relative superiority of keratin proteins to EMA immunoreactive staining for keratin proteins was diffuse intracytoplasmic and more uniform allover tumour tissue, compared to the prominent cell membrane localized, but less consistent reaction for EMA.The associated bilharzial reaction induced no detectable influence on distribution, intensity nor consistency of immunoreactivity for either tumour markers.Great variability in expression of both tumour markers was noticed in poorly differentiated carcinoma [2 adenocarcinomas were negative for keratin and positive for EMA and 2 squamous cell carcinomas were negative for EMA and positive for keratin proteins] which issues an advice to evaluate both tamour markers in poorly differentiated tumours in order to optimize detection of these neoplasms