Identification of breast cyst subpopulations: biochemical and morphological features.
The concentration of insulin-like growth factor-I (IGF-I) and its relationship to other biochemical parameters of cyst fluids was investigated in 94 cyst fluids of 86 women with gross cystic breast disease. The relationship between the biochemical parameters and the cytological features of breast fluids (presence or absence of apocrine cells) was also studied. IGF-I was detected in all tested fluids, with a concentration 50 to 100 times lower than that found in plasma. IGF-I concentration was higher in cysts with a Na+/K+ ratio greater than 3 (greater than 3) and was inversely related to both dehydroepiandrosterone sulfate (DHEA-S) and epidermal growth factor (EGF) concentration (p less than 0.001). It is suggested that Na+/K+ greater than 3 cysts have a higher permeability to plasma and extracellular fluids compared to Na+/K+ less than 3 cysts. Apocrine cells were found in 78% of Na+/K+ less than 3 fluids as well as in 53% of Na+/K+ greater than 3 fluids. A well-defined relationship was found between the biochemical parameters of breast fluids, but the presence of either IGF-I or EGF was not related to the morphology of breast cysts as assessed by cytological examination.