ALPHA(1)-ANTICHYMOTRYPSIN COMPLEXES IN HUMAN BREAST CYST FLUIDS

Alpha(1)-antichymotrypsin, a serum protease inhibitor, was found in 72 breast cyst fluids aspirated from women affected by gross cystic brea st disease. When fractionated by gel chromatography, the presence of p rotein complexes or aggregates was demonstrated. A different distribut ion of the alpha(1)-antichymotrypsin appeared to be related to the ion ic composition of the breast cyst fluid; when compared with metabolica lly active apocrine cysts, a statistically significant increase of alp ha(1) protease inhibitor values in flattened epithelial cysts was reve aled (P < 0.001). Two-dimensional immunoelectrophoresis showed in apoc rine cysts (Na/K ratio < 3) a characteristic double peak of alpha(1)-a ntichymotrypsin immunoprecipitin curve. The relationship between this alpha(1) protease inhibitor and electrolyte profiles may provide furth er knowledge about the imbalance between proteases and their inhibitor s on functional changes of gross cysts and might be useful in studies on their mechanism of formation and relationship to subsequent breast cancer.