Immunocytochemical localization of catechol-O-methyltransferase in normal and cancerous breast tissues

Immunocytochemical localization of catechol-O-methyltransfersase (COMT) by the peroxidase-antiperoxidase (PAP) technique has demonstrated the presence of the enzyme in normal and cancerous breast tissues of rodents and humans. Glandular epithelial, ductual epithelial, myoepithelial, capillary endothelial and fibroblast cells all exhibited reaction product indicative of the presence of COMT. Normal tissues were least reactive, and poorly differentiated, highly malignant tumors were most reactive. Staining intensities of lactating tissues or benign tumors were between the two extremes.