Determination of intratumoral estrone (E1) and estradiol (E2) in primary breast cancer tissues by sensitive HPLC-RIA

: The alternation of intratumoral estrogen metabolism has been indicated in breast cancer tissues. We determined the intratumoral concentrations of estrone (E1) and estradiol (E2) by a sensitive HPLC-radioimmunoassay (RIA) and analyzed its clinical significance in 74 primary breast cancer tissues. The average intratumoral concentrations of E1 were 48.6 + 7.3 pg/g w.w and 80.6 + 43.2 pg/g w.w in pre- and post-menopausal patients, respectively. The E2 concentrations were 168.7 + 36.8 pg/g w.w and 104.7 + 23.6 pg/g in pre- and post-menopausal patients, respectively. The background analysis demonstrated that intratumoral E2 levels were significantly higher in estrogen receptor (ER) positive tumors compared to ER negative tumors (p < 0.01). A significant correlation was also found between intratumoral E2 concentrations and progesterone receptor (PgR) status, indicating that E2 synthesis is frequently upregulated in hormone dependent tumors. These findings are important for studying the hormonal microcircumstances of Japanese breast cancer patients and also for considering the indication for clinical treatment using aromatase inhibitors.