The tumor-associated antigens BR55-2, GA73-3 and GICA 19-9 in normal and corresponding neoplastic human tissues, especially gastrointestinal tissues.

Immunohistochemical analysis with a monoclonal antibody, anti-BR55-2, was carried out on 163 tumors with their adjacent normal tissues and on 51 normal tissues from various organs by the ABC method. The expression of the antigen BR55-2 was compared with the expression of the colorectal carcinoma (CRC) associated antigens, GA73-3 and GICA19-9. BR55-2 was expressed in most normal epithelial tissues, whereas in the colon it seems to be exclusively a tumor-associated antigen. MAb55-2 might be of value in studying dysplastic lesions of the colon and in assessing the depth of invasion of CRC. In CRC, the expression of BR55-2 was complementary to that of GA73-3. MAb55-2 may therefore be of value in immunotherapy of CRC.