The use of a totally human monoclonal antibody for the staining of primary and metastatic human breast tumors.

: Numerous murine monoclonal antibodies reactive with human mammary tumor cells have been developed and used for identification of various breast tumor antigens. The problems encountered with these murine monoclonal antibodies include poor sensitivity and cross reactivity with normal tissue. We report here the use of a human monoclonal antibody (JDB1) as a more sensitive and specific method for staining of paraffin-embedded breast carcinoma tissue. This human clone was constructed by fusing the human lymphoma cell line (Ball-1) and peripheral blood lymphocytes from a breast cancer patient in active immunological remission of her disease. Several benign and malignant breast lesions in addition to a variety of apparently normal human tissues have been stained. To date, a variety of breast carcinomas have stained positively with JDB1, while normal breast tissue samples as well as other forms of malignant tissue were negative for staining. In addition, unlike most commercially available murine monoclonals, JDB1 was able to identify metastatic infiltrating ductal carcinoma to both axillary nodes and skin. These results represent one of the first reported findings of immunostaining using a human monoclonal antibody on paraffin-embedded formalin-fixed human breast carcinoma. These human antibodies provide new research tools with which to evaluate human breast cancer and allow for a more complete understanding of the heterogeneity associated with this disease.