Sialylated Lewis determinant CA 19-9 in benign and malignant gastric tissue.

The expression of the carbohydrate antigen CA 19-9 in human gastric mucosa was studied by using the monoclonal 1116 NS 19-9 antibody, immunohistochemical ABC staining technique and formalin-fixed, paraffin-embedded biopsy specimens. Among 26 gastric carcinoma (GCA) patients CA 19-9 antigen was found in 16 patients (62%). The antigen was also found in 10 (48%) out of 21 non-cancer patients who had benign gastric ulcer and in 9 (12%) out of 74 non-ulcer, non-cancer patients. In non-cancerous mucosa, the CA 19-9 antigen was localized in the surface epithelium (foveolar type of staining) and/or in goblet cells and sometimes in absorptive epithelium of metaplastic intestinal glands (goblet cell type). The foveolar type but not the goblet cell type was related to the nonsecretor status of the subject, to Le positivity and to anti-H negativity of the gastric surface epithelium. It is concluded that, although being commonly present in GCA tissue, the expression of the antigen in benign gastric tissue is too common to advocate the practical value of CA 19-9 in predicting malignant gastric lesions in immunohistochemistry.