Cytokines in human breast cyst fluid

Gross cystic breast disease is a common benign disorder in which palpable cysts occur in the breast and are normally treated by aspiration of the contents. The cysts are classified as either Type 1, containing a high level of potassium ions and a low level of sodium ions, or as Type 2, with low potassium and high sodium ion concentrations. Steroid sulphatase activity in MDA-MB-231 and MCF-7 cell lines is regulated by exogenous breast cyst fluid (BCF), possibly because of cytokines in the BCF. A screening method was used to determine the range of cytokines in eight BCFs, four of each type. This was an array system, which uses antibodies immobilised on a membrane to qualitatively detect 79 different cytokines or growth factors. Nine cytokines were detected well above background levels: all were found in both types of BCF, but only epidermal growth factor (EGF) was higher in Type 1. All the other factors were higher in Type 2 BCF. Two of these cytokines, IL-6 and EGF, have previously been suggested to affect steroid sulphatase expression and several (MIP-1β, IL-8, NAP-2) are known to affect MCF-7 cell chemotaxis. In addition two cytokines were measured by ELISA in 57 BCFs, and both IL-1β and IL-13 were found in BCF, with significantly higher amounts of IL-1β in Type 1 than Type 2 BCF (35.5 ± 4.4 pg/ml versus 9.9 ± 2.9 pg/ml).