Concurrent immunohistochemical staining of tumor-infiltrating lymphocytes and carcinoma-associated T (Thomsen-Friedenreich)/Tn antigens in human breast carcinoma.

The composition of tumor-infiltrating lymphocytes (TIL) often reflects the host's immune response to the tumor. To study the relationship of TIL and carcinoma-associated T/Tn antigens in breast carcinoma, a straightforward concurrent immunoenzyme staining procedure was developed. Fresh tissue was directly fixed in a zinc-based fixative to preserve lymphocyte markers and then routinely embedded in paraffin. The TIL subtypes in the sections were identified in the first immunostaining cycle by reaction with a monoclonal antibody (MAb) to lymphocyte markers CD3, CD4, CD8, CD19, or CD56, followed by a modified avidin-biotin procedure and diaminobenzidine tetrahydrochloride-H2O2 for color development. This was followed by paraformaldehyde fixation to block antibody crossreactivity. The T and Tn antigens on carcinoma cells were then demonstrated in a second staining cycle by reaction with an MAb against T or Tn antigen, followed by an indirect immunoalkaline phosphatase procedure and corresponding substrate systems for color development. The distinguishable brown color for TIL and blue or red color for T or Tn antigen enabled us to identify the TIL subsets and to describe their relations with T/Tn antigen expression in situ. This approach may contribute to better understanding of the patients' immune defenses against their tumor and aid in prognostication.