Impact of physiological hormonal fluctuations on

Premenopausal physiologic steroid levels change cyclically, in contrast to steady state low levels seen in postmenopausal patients. The purpose of this study was to evaluate whetherA total of 160 primary invasive breast cancers from 155 females (54 premenopausal, 101 postmenopausal) who underwentAmong premenopausal patients, SUVmax during the periovulatory-luteal phase was significantly higher than that during the follicular phase in luminal A-like tumors (n = 25, p = 0.004), while it did not differ between the follicular phase and the periovulatory-luteal phase in luminal B-like (n = 24) and non-luminal tumors (n = 7). Multiple regression analysis showed menstrual phase, tumor size, and Ki-67 index are independent predictors for SUVmax in premenopausal luminal A-like tumors. There were no significant differences in SUVmax between pre- and postmenopausal patients in any of the subgroups. In in vitro studies, uptake in estrogen receptor-positive cells was significantly augmented when E2 concentration was increased from 0.01 to ≥ 1 nM.Our data suggest that