Demonstration of lactoperoxidase in paraffin-embedded lactating bovine breast by immunocytochemical techniques.

Immunocytochemical methods have been applied to the demonstration of lactoperoxidase (LP) in the lactating bovine breast. Trypsin digestion and a MAGIC (Wachsmuth ED: Histochemie, 37:251, 1973) procedure, using anti-LP serum and then LP solution in sequence, made the sensitive and specific demonstration of LP in formalin-fixed paraffin-embedded sections possible. Peroxidase of the breast has been shown to be inducible by estrogen stimulation and it is considered to be a possible marker of estrogen dependency in breast carcinomas. The present technique, applied to human tissues, even on fixed and embedded biopsies, might make possible the detection of LP in human breast cancers and, thereby, an evaluation of estrogen dependency of such cancers.