Immunocytologic losses of isoantigens A, B, and H (O) in the endometrium and brain.

Formalin-fixed tissues from 100 endometria and 50 brains were grouped and studied by the technic of mixed-cell agglutination reaction (MCAR) for studying isoantigens A, B, and H (O). MCAR's were negative in all 45 of the endometria from subjects with endometrial carcinomas, where as MCAR's were positive in the epithelium of endometrial glands of the remaining 55 subjects (cyclic phases of endometrium and benign lesions). MCAR's were negative in all benign and malignant brain tumors and normal brain tissues used in this study. In view of the present findings and in the light of previous observations, the isonatigen loss in adenocarcinomas is greater than such losses in other types of malignancies so far studied. The cause of the negative MCAR's in normal brain tissue and brain tumours is not known, but they may be attributable to lack of isoantigens in normal brain tissue.