Background: It has been thought that carbohydrate antigens, especially Lewis (Le) blood group antigens, are cancer-related antigens.
Methods: The authors conducted immunohistochemical studies to investigate the expression of seven different types of Le carbohydrate antigens in breast cancer tissue and their usefulness as an indicator of the degree of malignancy and as a prognostic factor.
Results: When this expression was compared in the cancerous portion of 300 breast cancers and noncancerous mammary ductal epithelium in each of the patients, reduced expression of type 1 carbohydrate antigens and increased expression of type 2 carbohydrate antigens were found in the cancerous portions. No correlation was detected between the antigen expression and clinicopathologic factors. The prognosis of patients in whom type 2 carbohydrate antigens were increased in the cancerous portion, especially Lex (19.7% of patients) and sialyl Lex-i (20.3% of patients), was poorer than in patients in whom they were not increased (P < 0.01).
Conclusions: The relative expression of type 2 carbohydrate antigens in breast cancer tissue seems capable of serving as a prognostic factor.