Quantification of pepsinogen C and prostaglandin D synthase in breast cyst fluid and their potential utility for cyst type classification

Objective: To quantify pepsinogen C (PEPC) and prostaglandin D synthase (PGDS) in breast cyst fluid and examine if these two parameters can be used for breast cyst type classification. Design and Methods: We quantified PEPC and PGDS in 92 and 50 breast cyst fluids, respectively, using previously established immunofluorometric procedures. We then examined if the levels of PEPC or PGDS correlate with the type of cyst or with other clinicopathological variables. Results: Quantitative analysis of the breast cyst fluids indicated that PEPC is present in all cyst fluids at various concentrations ranging from 3 to 31,000 ng/mL. PGDS positivity was confined to 30% of the cyst fluids. PEPC and PGDS levels were correlated with the breast cyst fluid cation ratio and were associated with the type of the cyst. Increased PEPC levels in breast cyst fluids were significantly correlated with a greater than or equal to 1.5 K+/Na+ ratio and were associated with the secretory/apocrine type of cyst (Type I) (p = 0.011). Immunoreactive PGDS levels were highly correlated with a low cation ratio and were associated with the transudative/flattened type of breast cyst (Type II) (p = 0.0003). A weak association was observed between PEPC levels in breast cyst fluid and menopausal status (p = 0.093). No significant associations were observed for either PEPC or PGDS concentration in breast cyst fluid and number of cysts, recurrence of the disease, family history of breast cancer, number of children, abortion, and breast feeding. Conclusions: Quantification of PEPC and PGDS in breast cyst fluid may be useful in the subclassification of cyst type in patients with gross cystic disease. Copyright (C) 1999 The Canadian Society of Clinical Chemists.