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

Objective: To quantify pepsinogen C (PEPC) and prostaglandin D synthase (PG DS) in breast cyst fluid and examine if these two parameters can be used fo r breast cyst type classification. Design and Methods: We quantified PEPC and PGDS in 92 and 50 breast cyst fl uids, respectively, using previously established immunofluorometric procedu res. 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 PEP C 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 an d were associated with the type of the cyst. Increased PEPC levels in breas t 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 c yst (Type I) (p = 0.011). Immunoreactive PGDS levels were highly correlated with a low cation ratio and were associated with the transudative/flattene d type of breast cyst (Type II) (p = 0.0003). A weak association was observ ed between PEPC levels in breast cyst fluid and menopausal status (p = 0.09 3). No significant associations were observed for either PEPC or PGDS conce ntration in breast cyst fluid and number of cysts, recurrence of the diseas e, family history of breast cancer, number of children, abortion, and breas t feeding. Conclusions: Quantification of PEPC and PGDS in breast cyst fluid may be us eful in the subclassification of cyst type in patients with gross cystic di sease. Copyright (C) 1999 The Canadian Society of Clinical Chemists.