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.