Identification of T and B lymphocytes in human breast cancer with immunohistochemical techniques.

Cryostat sections of 50 breast cancer specimens and several lymphoid organs were investigated with antisera against human T-lymphocyte antigen, human lymphocytes, and human immunoglobulins using the immunofluorescence technique and the immunoperoxidase technique. These methods proved to make it possible to discriminate between T and B cells in lymphocytic infiltrates in tissue sections. In nearly all mammary carcinomas studied, T cells were found to predominate in and around tumor cell nests. Only the intraductal carcinomas of this series contained a substantial number of B cells in addition to T cells. The presence of T cells indicates that the host-tumor interaction in vivo mall-mediated immune reaction. The role of the B cells found in the lymphocytic infiltrates of the intraductal carcinomas is still a matter of speculation. Moreover, these findings enhance the value of established histologic classifications. These classifications may have to be modified to provide them with a more functional basis.