Isoantigens A, B and H in benign and malignant lesions of breast.

Eighty-five specimens of breast tissue were grouped and investigated by the technic of mixed cell agglutination reation (MCAR) for studying isoantigens A, B and H (O). MCAR was found to be strongly positive at the epithelium of acini in all the 25 subjects with benign lesions (10 fibroadenomas, 10 cystic mastitis and 5 gynecomastias). On the other hand, all the subjects with diagnosis of primary carcinomas in breast (45 subjects) and their metastases (15 subjects) were found to be uniformly negative for any agglutination reaction. In view of these findings, it seemed that the isoantigens in primary and metastatic malignancies of breast are always lost, while in the benign lesions isoantigens are always present. Although the exact mechanism is not understood, it seems that, in malignancies with a glandular differentiation, some differences exist when these are compared to malignancies with a squamous differentiation. The various possibilities are discussed in the light of previous studies.