ABSTRACT
Gross cystic disease (GCD) of the breast is a premenopausal disorder in which gross cysts are the predominant pathologic lesion. This entity is associated with an increased risk for the development of breast carcinoma [1]. The stimuli that induce apocrine metaplasia of the breast lobular epithelium and the formation of gross cysts from apocrine microcysts are unknown. One approach to the understanding of the pathophysiology of this transformation has been to analyze the fluid aspirated from the gross cysts. Biochemical analysis of the cyst fluid has shown that it contains four major component proteins [2-4]. One of these proteins, gross cystic disease fluid protein-IS (GCDFP-15) has been extensively characterized biochemically and has been used to prepare polyclonal and monoclonal antibodies for clinical and pathological studies. GCDFP-15 appears to be a marker of apocrine glandular epithelium in both benign and malignant states [4,5].
