Immunohistochemical evaluation of nonspecific cross reactive antigen and carcinoembryonic antigen (CEA) in urinary bladder carcinoma

The immunohistochemical expression of CEA in formalin-fixed paraffin sections in urinary bladder carcinomas was compared to the use of polyclonal anti-CEA antiserum (P-CEA), NCA-absorbed anti-CEA (NCA-aCEA) and monoclonal antibody to CEA (M-CEA). The urinary bladder carcinomas examined consisted of 19 cases of transitional cell carcinoma (TCC) and 7 cases of squamous cell carcinoma (SCC). Both TCC and SCC were positive for CEA with the use of P-CEA and NCA-aCEA, and the degree of staining was markedly dependent on the grade of malignancy in TCC. However, the reaction to M-CEA was generally very weak or negative in TCC and SCC. In SCC, the staining reaction was confined to keratinized foci and not found in all malignant tumour cells when polyclonal CEA antiserum was used. These findings indicate that positive reactions seen with conventional CEA antibodies (P-CEA and NCA-aCEA) are possibly related to NCA and that urinary bladder carcinoma may contain relatively more NCA than true CEA.