EXPRESSION OF LEWIS(X), SIALYLATED LEWIS(X), LEWIS(A), AND SIALYLATED LEWIS(A) ANTIGENS IN HUMAN LUNG-CARCINOMA

One hundred and five cases of various human lung neoplasms were studied immunohistochemically using monoclonal antibodies recognizing the antigens, Le(x), sialylated Le(x) (SLEX), Le(a), and sialylated Le(a) (SLEA). Of the 92 lung cancers examined for antigen expression SLEX was detected in 57% (52 cases), Le(x) in 42% (39), SLEA in 36% (33), and Le(a) in 23% (21). None of these antigens were expressed in 9 tumor like lesions of the lung or the 4 other non-epithelial malignant lung tumors examined. Higher expression was seen in the 54 lung adenocarcinomas: SLEX in 72%, Le(x) in 48%, SLEA in 39%, and Le(a) in 24%. The type 2 carbohydrate antigens (SLEX and Le(x)) were more prevalent than the type 1 antigens (SLEA and Le(a)) in lung adenocarcinoma tissues. In adenocarcinomas, SLEX was expressed in 71% (10/14) of the Le(b) patients, and in 100% (5/5) of the Le(a) patients. Unexpectedly, SLEX was not detected in 4 out of 5 Le(a-b)- patients tested. This suggests that the expression of the Le(x) antigens and the Le(a) antigens are related in lung adenocarcinoma. These antigens were less expressed in other types of lung cancers. Tissue sections obtained serially showed heterogeneity in the expression of these antigens, as evidenced by the concurrent presence of both SLEX and SLEA. These results indicate that SLEX is a useful tumor-associated marker for lung adenocarcinomas, and that terminal fucosylation and sialylation may be activated heterogeneously in these lung cancers.