EPIDERMAL GROWTH-FACTOR AND ESTRADIOL IN HUMAN BREAST CYST FLUID

Gross cystic breast disease is a common condition in women. Women with apocrine breast cysts (breast cyst fluid Na+/K+ < 3) may be at higher risk of breast cancer than women who have cysts lined by flattened epithelium (Na+/K+ ≥ 3). Breast cyst fluid concentrations of epidermal growth factor were significantly higher in the low electrolyte ratio group than in the high electrolyte ratio group (356.2 ng/ml vs 104.1 ng/ml, P < 0.0003). A negative correlation was obtained between intracystic epidermal growth factor concentrations and Na+/K+ (rs = -0.666, P < 0.001). No significant difference was found between the total oestradiol concentrations in the two cyst groups. However, the unbound oestradiol concentrations on a limited number of samples were significantly higher in the low electrolyte ratio group than in the high electrolyte ratio group (P < 0.05). The higher concentrations of EGF in cyst fluid with Na+/K+ < 3 may explain why women with apocrine breast cysts may be at increased risk of developing breast cancer. © 1990.