Fucosylated type‐2 chain polylactosamine antigens in human lung cancer

Abstract

Four specific monoclonal antibodies (MAbs) have been used to study distributions of fucosylated type‐2 chain polylactosamine antigens, Le^x, poly Le^x, Le^y and sialylated Le^x‐i antigens, in human lung cancer tissues and in the serum of patients with lung cancers. Radioimmunoassay frequently showed abnormally high antigen levels in the sera of 66 lung cancer patients tested. When histological typing was performed, high serum levels of the above 4 antigens were most frequently observed in patients with adenocarcinoma of the lung; i.e., after combining the results from the 4 antigens, 75% of the sera from patients with lung adenocardnoma were positive (50% in the case of large‐cell carcinoma, 30% in the case of squamous‐cell carcinoma and 27% for small‐cell carcinoma). Among the 4 antigens, the sialylated Le^x‐i antigen had the highest positive incidence, 58%, in the sera of patients with adenocarcinoma of the lung, compared to 33% for Le^y 29% for poly Le^x, and 8% for Le^x antigen. On the other hand, when the distributions of these antigens in the lung cancer tissues of 42 patients were studied by immunohistological techniques, the Le^x antigen had the highest positive incidence, 100%, in lung adenocarcinoma tissues, poly Le^x antigen had 86%, sialylated Le^x‐i antigen had 71%, and Le^x antigen had 29%. In cancer tissues, the incidence of non‐sialylated antigens, such as Le^y, poly Le^x and Le^x antigens, often exceeds the positive incidence of the sialylated antigen, but the sialylated form of the antigen, such as sialylated Le^x‐i antigen, appears more often than the non‐sialylated form in patients' sera.