Expression of GCDFP-15 in breast carcinomas. Relationship to pathologic and clinical factors.

A retrospective immunoperoxidase staining study for a glycoprotein isolated from human breast gross cystic disease fluid (GCDFP-15) in 562 primary breast carcinomas in 539 patients was conducted to correlate its immunohistochemistry with pathologic and clinical factors. Overall, 55% of the carcinomas studied stained positively for GCDFP-15. In certain histologic subtypes, the percentage of carcinomas that stained positively was greater: those subtypes with apocrine histologic features (75%), intraductal carcinoma (70%), and infiltrating lobular carcinoma with signet-ring cell differentiation (90%). In contrast, only 5% of medullary carcinomas exhibited positive staining. Only 23% of breast carcinomas without apocrine features stained positively for GCDFP-15. Carcinomas that stained positively were more likely to have involved axillary lymph nodes (P less than 0.054). The staining was independent of nuclear grade, mitotic index, tumor size, and estrogen receptor status. Positive staining was related to a history of gross cystic disease but not to age, parity, menopausal status, or age at first birth. A positive stain was not related to risk of recurrence or survival.