Immunofluorescence studies of benign and malignant human mammary tissue.

Indirect immunofluorescence studies on sections of human normal breast tissue, benign breast lesions, and breast adenocarcinomas were performed with the use of monospecific fluorescein-conjugated antisera to human alpha, gamma, and mu chains, albumin, and C3. In all tissues, benign and malignant, immunohistologic localization of IgA and IgM was noted in patterns previously described for other secretory epithelia. IgG was localized at the tumor cell, but was not associated with epithelial cells from either normal breast tissue or benign breast lesions. Except for a single case of benign cystosarcoma phylloides, all normal, benign, and malignant breast tissues failed to react with anti-C3. These findings were compared with previous studies employing dissociated tumor cells, and the potential application of these methods to pathologic diagnosis was examined.