Immunoglobulin localization in benign and malignant lesions of the human mammary gland

Using direct immunofluorescence, lesions from 266 human breast specimens were studied for the presence of IgA, IgM, or IgG localization. The lesions included benign elements from 66 subcutaneous mastectomy specimens in which the absence of simultaneous breast malignancy was documented, primary breast carcinomas from 153 mastectomy specimens, and 47 biopsies containing metastatic breast cancer. A statistically significant association of IgA and IgM with benign lesions was contrasted to the association of IgG with malignant lesions. In both primary and metastatic lesions, IgG localization was associated with estrogen-receptor-poor primary cancers as compared with estrogen-receptorrich primary cancers. Among primary breast cancer patients, IgG localization in the tumor correlated with relative lymphopenia. A shorter disease-free interval was noted in association with IgG localization among the metastatic breast lesions. No statistically significant association between stage of disease and immunoglobulin presence was demonstrable. Moderate-to-severe intraductal epithelial hyperplasias were more often associated with immunoglobulin G localization than were other benign lesions. Cancer 48:69-75, 1981. EVERAL STUDIES have suggested a role of the host S immune response in the natural history of mammary car~inoma.~~,~~ The breast is a component of the secretory immune system, concentrating immunoglobulins in breast A differential concentration of immunoglobulins in benign vs. malignant lesions of the breast has been suggested.s,20,21 The accumulation of immunoglobulin A (IgA) and immunoglobulin M (IgM) in the mammary gland have been shown to be induced by hormones.23 In the present study the localization of IgA, IgG, and IgM observed in various breast lesions was compared with the estrogen receptor content of the tissues. Benign and malignant lesions were examined to determine if immunoglobulin localization may characterize primary and metastatic breast cancers as contrasted to benign breast lesions.