Antibodies to mouse mammary tumor virus-related antigen in sera of patients with breast carcinoma.

Sera from patients with breast carcinoma, benign breast disease, malignancies other than breast carcinoma, and healthy female controls were analyzed by indirect immunofluorescence for the presence of antibodies directed toward antigens of mouse mammary tumor. Sera from 56 to 137 (40.9%) patients with breast carcinoma were positive. Positive reactivity was also found in sera from 5 to 27 (18.5%) patients with benign breast disease, in 7 of 60 (11.7%) patients with malignancies other than breast carcinoma, and in 2 of 56 (3.6%) female controls. In the group of patients with breast carcinoma a correlation was noted between age and the probability of detection of these antibodies. Histopathologic examination of breast cancers indicated that antibodies to antigens in mouse mammary tumors were more often found in patients with infiltrating ductal carcinoma of the mucinous type than with other types of breast tumors. No correlation was demonstrable between the incidence of detection of these antibodies and the stage of the disease. Immunochemical analyses indicated that the antibody activity was present in IgG and IgM classes of immunoglobulins. The human antibodies to antigens in mouse mammary tumors could be removed from patients' sera by absorption with disrupted mouse mammary tumor virus (MMTV) but not with gp52 or gp34 (52,000 and 34,000 dalton polypeptides) of MMTV, or with Rauscher mouse leukemia virus (MLV).