A continuous presence of Estradiol has an opposite effect compared to a hormonal imbalance simulation. (A) Morphological evaluation of CSC-enriched cell cultures after 1 and 10 nmol l−1 continuous E2 treatment, and with hormonal imbalance simulation (magnitude 10×; optical microscope). (B) Mean Fluoresce Index of FACS analysis for SOX2, OCT3, NANOG, ERA, ERB, and GPER1. UNTREAT = control; E2 TREAT = cells after 7-days treatment; STOPPING TREAT = cells after stopping treatment for further 7 days. * = P < 0.005.