Altered expression of Lewis blood group and related antigens in fetal, normal adult and malignant tissues of the uterine endometrium.

The expression of the Lewis blood group and its related antigens in fetal, normal adult and malignant tissues of the uterine endometrium was examined immunohistochemically using a panel of mouse monoclonal antibodies with specificities for Lewis-a (La), Sialyl Lewis-a (SLa), Lewis-b (Lb), Lewis-X (LX), Sialyl Lewis-X (SLX) and Lewis-Y (LY) antigens. La, SLa and SLX having one fucose residue were detected in a small number of fetal tissues, while Lb and LY having two fucose residues were found in most cases. In the adult endometrium, expression of Lb and LY was considerably lower than those in fetal tissues, although expression of La and SLa was not different between these two tissues. Expression of LX and SLX was pronounced in adult when compared with fetal tissues. Malignant endometrial glands expressed La, SLa, Lb and LY, extensively, while LX and SLX were expressed less than in normal tissues. Lb and LY can thus be considered oncofetal antigens, extensively expressed in fetal and malignant tissues but not in normal adult tissues. Expression of Lb and LY was greater than that of La and SLA in carcinoma; an increase in the activity of fucose transferase might be associated with malignant transformation in the uterine endometrium.