Immunohistological investigations of carcinoembryonic antigen (CEA) in urothelial carcinomas.

CEA is discussed as a potential tumour marker for carcinomas of the urothelium. However, investigations by means of polyclonal antibodies have shown various cross reactions which are not to be expected with monoclonal antibodies (MAb). Immunohistochemistry was done with the MAb anti-CEA BW 431/26 (Behring), N 1522 (Dako), and C 7292 (Sigma) on 37 carcinomas of the urothelium (grades 1-3). The MAb BW 431/26 showed the best results concerning specificity and sensitivity. In general, immunohistological investigations demonstrated negative or moderate staining reactions. Positive reactions were seen in 32% (12/37) of the carcinomas. Staining intensity for CEA correlated with differentiation grade. On the whole, a maximum of 5% of the tumour cells were CEA positive. Our results indicate that monoclonal anti-CEA antibodies are not usefull as a tumour marker for urothelial carcinomas. For the suitability of CEA for in vitro and for in vivo diagnosis a threshold of CEA positive tumour cells has to be defined.