GCDFP-15 (23A3)

GCDFP-15 is a 15 kD glycoprotein which is localized in the apocrine metaplastic epithelium lining breast cysts and in apocrine glands in the axilla, vulva, eyelid, ear canal, and in salivary glands.1 Approximately 70% of breast carcinomas are labeled with antibody to GCDFP-15.2 Colorectal carcinomas, lung carcinoma, mesothelimas rarely stain with this antibody.3 Because of its specificity for breast carcinoma (up to 99%3), this antibody is often used in a screening panel in the appropriate clinical situation, often for a woman with metastasis of unknown primary.4