Correlation of concentrations of estriol-3-sulfate with those of potassium and sodium in human breast cyst fluid.

Estriol-3-sulfate (E3-3S) was assayed in 92 specimens of human breast cyst fluid (BCF) obtained by needle aspiration from women with fibrocystic disease. The concentrations of K+ and Na+ were determined in the same samples. The median concentration of E3-3S in the fluids from premenopausal women under 51 years of age (69 cases) was 4.4 ng/mL. Based on the K+ levels the samples were divided into two groups, above 50 mM (Type I) and below 50 mM (Type II). Correlations were made between the concentrations of the estrogen conjugate and the univalent ions. In the premenopausal women, Type I cysts were associated with above median E3-3S and Type II cysts with below median E3-3S (P less than 0.01). A K+/Na+ ratio of more than one was also related to elevated E3-3S (P less than 0.025). The BCF obtained from postmenopausal women and women older than 50 years tended to be low in E3-3S (median 1.64 ng/mL) and high in K+ but there were too few cases to permit statistical comparisons to be made. Since fibrocystic disease constitutes a risk factor for the development of breast cancer, it will be of interest to determine retrospectively whether any of the above subsets of BCF may be useful in identifying a patient at such risk.