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

Using direct imunofluorescence, 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-receptor-rich 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 that were other benign lesions.