Antiserum against formalin-fixed human milk fat globule glycoprotein for immunohistochemistry of normal and malignant apocrine epithelium

A rabbit antiserum was raised against formalin-fixed glycoprotein isolated by lectin affinity chromatography from human milk fat globules. After adsorption with erythrocytes and normal blood leukocytes the antiserum detected in immunoblotting of fresh mammary carcinoma tissue a major component of 75 000 dalton apparent molecular weight. The antiserum specifically decorated normal and malignant apocrine epithelium in sections of formalin-fixed tissues. The usefulness of such antisera for routine immunohistochemical diagnosis of metastatic carcinomas is demonstrated.