Estrogen sulfurylation as an alternative indicator of hormone dependence in human breast cancer

Estrogen receptor (ER) levels, formation of 3'-phosphoadenosine-5'phosphosulfate (PAPS), and sulfate transfer to estradiol-178, have been determined in 62 human primary carcinoma cytosol preparations. Whilst no differences between ER positive and ER negative tumors were found in the synthesis of [35S]PAPS, formation of estradiol-3-[35S]sulfate catalysed by estrogen sulfotransferase was significantly higher in ER positive tumors [84 +/- 10 (mean +/- S.E.M.) versus 32 +/- 9 pmole estradiol-3-sulfate per mg protein per 2 hr for ER positive and ER negative tumors, respectively, p less than 0.02]. By choosing a discriminating value for estrogen sulfurylation of 40 pmole per mg protein per 2 hr, then 16/19 (84%) of the ER negative tumors were below this point. Since previous data had shown that 20/23 (87%) progesterone receptor negative tumors were also below this value (Pewnim, Adams and Ho, CANCER RES. 40, 1360 (1980), an alternative simple method, having a high potential for the evaluation of hormone responsiveness in mammary cancer, is suggested.