A fluorescent probe for rapid detection of estrogen receptors

B. Ramanath Rao, C. Glenn Fry, Steven Hunt, Radka Kuhnel, Walter B. Dandliker

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Fluorescein conjugates to estradiol‐17β by the sixth carbon (6‐FE) and to estrone by the 17th carbon (17‐FE) were used to detect estrogen receptors (ERs) in breast cancer tissue sections and in cultured ceil lines (human mammary carcinoma MCF‐7 and Copenhagen rat prostatic tumor R3327‐AT). 17‐FE was found to interact with ERs better than 6‐FE by biochemical and histochemical techniques. Thin layer chromatography analysis of ethanolic extracts of 17‐FE incorporated in tissues and cultured cells showed that over 95% of 17‐FE was not metabolized. We concluded that the fluorescence observed in tissue sections and cultured cells was due to 17‐FE and not to fluorescein dissociated from the conjugate. Analysis of 65 human breast cancer showed that 74% of the cases were positive for specific 17‐FE uptake and 26% were negative. The fluorescence was consistently brighter in the ductal and glandular epithelial cells than in the stroma. Specific 17‐FE uptake in the nucleoli was observed in MCF‐7 and in R3327‐AT tumor cells in in vitro cultures, suggesting that these nucleolar estrogen receptors may play a key role in the mechanism of estrogen action. Problems of fluorescence quantitation in tissue sections and cells are discussed.

Original languageEnglish
Pages (from-to)2902-2906
Number of pages5
Issue number12 S
StatePublished - Dec 15 1980


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