Expression of blood group antigens A, B, H, Lewis-a, and Lewis-b in fetal, normal, and malignant tissues of the uterine endometrium.

Fetal, normal adult, and malignant tissues of the uterine endometrium were examined by immunoperoxidase staining for the blood group antigens (BGA) A, B, H, Lewis-a, and Lewis-b. Antigens A, B, and H compatible with the ABO status of fetuses were detected in 20 of the 22 fetal tissues that were examined. Lewis-b immunoreactivity was also found in 21 fetuses, and Lewis-a was present in a third of the cases. In adult endometrium the expression of BGA H and Lewis-b was considerably lower than in fetal tissues. Malignant endometrial glands extensively reexpressed H and Lewis-b regardless of ABO status. BGA A and B were neither absent nor accumulated in cancer tissues. Thus, H and Lewis-b can be considered as oncofetal antigens since they were frequently expressed in fetal and cancer tissues, but not in normal adult tissues. The increased expression of Lewis-a antigen might be associated with malignant transformation as it was observed only in malignant tissues. However, the functional significance of alterations in BGA expression that may be associated with oncogenesis remains to be investigated.