CEA and carbohydrate antigens in normal and neoplastic colon mucosa. An immunohistochemical study.

Antibodies raised against tumour-associated antigens have been assessed for tumour selectivity using an indirect immunohistochemical peroxidase staining of formalin-fixed, paraffin-embedded tissue from colon carcinomas, colon polyps and normal mucosa. The following antibodies were used: 1) Unabsorbed polyclonal antibody to carcinoembryonic antigen (poly-CEA). 2) Monoclonal antibodies to CEA (mabs 3851 and 27). 3) Monoclonal antibodies to protein-bound carbohydrates (mabs C 216 and C 242) or to lipid- and protein-bound carbohydrates (C 50 and 19-9). These antibodies had been produced by hybridization of lymphocytes from mice, immunized with colon carcinoma cell lines or colon cancer tissue. All antibodies were used in one concentration only, preselected by initial titration experiments. No antibody was completely tumour-specific, but four antibodies, mabs 3851, 27, C 216 and C 242, showed statistically significant tumour selectivity. Using these antibodies, respectively 19, 19, 19, and 18 of 20 colon cancer were stained compared with 3, 4, 4, and 8 of 15 specimens of colon mucosa from normal controls. An increased frequency of staining was also noted in dysplastic polyps (statistically significant using mabs 3851 and C 216) and in dysplastic mucosa adjacent to a tumour (statistically significant using mabs 3851 and 27). The staining frequency of normal colon mucosa in cases of colon cancer did not differ from that in the normal controls. Poly-CEA and the anti-ganglioside mabs C 50 and 19-9 revealed no tumour selectivity. A pronounced goblet cell staining was seen using C 50, C 242 and 19-9.