Expression Of Estrogen Sulfotransferase 1E1 And Steroid Sulfatase In Breast Cancer And Adjacent Non-malignant Tissue

Estrogen plays an important role in the development and progession of estrogen dependent breast carcinoma. Approximately 95% of breast cancers are estrogen-dependent in their early stage, whether in premenopausal or postmenopausal women. However, two-thirds of breast cancers are diagnosed after menopause, when the ovarian exhaustion leads to a dramatic decrease of E2 serum levels. Interestingly, it was determined that the intratumoral E2 concentration in postmenopausal patients is however maintained at a level similar to that found in premenopausal patients. This observation suggests an intratumoral biosynthesis of E2. One important pathway responsible for the tumoral production of E2 is the desulfation of the inactive estrone sulfate (E1-S) by the steroid sulfatase (STS), an enzyme ubiquitously expressed in many organs and particularly in breast carcinoma tissue. Once desulfated , E1 is subsequently reduced into E2 by the 17β-hydroxysteroid dehydrogenases (17β-HSD) types 1, 7 and12. E1-S is the most abundant circulating estrogen in postmenopausal women and its levels are 7 to 11 times higher in tumor tissues than in circulation.In opposition to the STS action, E1 and E2 can be transformed into inactive E1-S or E2-S by the estrogen-preferring sulfotransferase .So far, several SULT enzymes have been identified, including SULT1A1, 1A2, 1A3 and 1E1. However, the 1E1 enzymes, also known as estrogen sulfotransferase (EST1E1) is the one which have the highest affinity for estrogens. STS and EST1E1 combined action could maintain the equilibrium between sulfated and unconjugated estrogens, which might have effects on genesis and development of hormone dependent breast cancer.Through the studying of the expression of EST1E1 and STS in breast cancer and adjacent non-malignant tissue, and the correlations between the results and the clinical factors, we want to analyze the strength of the expression of EST1E1 and STS and the role of the two enzymes in the metabolism of sex steroid. We also analyze the relationship among the sex steroids by studying the correlation among the sex steroid receptors.Prepare the protein of EST1E1 and STS, injected sc with 1ml at multiple sites of New-Zealand rabbits. Collect the antiserum of the rabbits and purify it. Positive antiserum was analyzed by immunoblot. The expression of EST1E1 and STS and CDC-47,ERα,ERβ,PRA,PRB in 88 specimens of female human breast carcinoma and adjacent non-malignant tissues were studied by immunocytochemistry. These results were correlated with the clinical parameters.Results:1,Immunostaining for STS was almost exclusively cytoplasmic.It was seen in the cytoplasm of malignant cells in all the cancer cases: 31 invasive carcinomas (35.2%) were 1+and 57 (64.8%) were 2+. In non-malignant adjacent tissues, STS staining was seen in the epithelial cells of both acini and ducts in 55 out of 57 samples (96.5%): 28 (49.1%) were 1+ and 27 (47.4%) were 2+. The expression degree of stained cells was higher in the invasive carcinomas than in the normal adjacent tissues, and there was a significant difference(χ2= 5.498,P<0.05 ). Cytoplasmic and nuclear staining for EST1E1 was observed in 83 out of 88 invasive carcinomas (94.3%): 30 (34.1%) had between 1-50% stained cells and 53 (60.2%) had more than 50% stained cells.EST1E1 immunoreactivity was also found in 55 out of 57 adjacent normal tissue samples (96.5%). The staining was detected in the cytoplasm and nuclei of stromal cells and epithelial cells in both acini and ducts. Among the positive tissues, 23 (40.4%) had between 1-50% stained cells and 32 (56.1%), had more than 50% stained cells. We could not measure any significant differences between the EST1E1 expression in invasive carcinomas and that observed in adjacent normal tissues . 2,Immunostaining for ER-α, PR-B as well as CDC47 was exclusively observed in nuclei of epithelial cells in both non-tumoral adjacent tissues and carcinomas. Immunoreactivity for ER-βand PR-A was also found in normal epithelial cells and in tumoral cells but the staining was both nuclear and cytoplasmic. The expression of CDC47 was significantly higher in tumors than in adjacent normal tissues (p < 0.001). The expression of ER-αwas also significantly higher in the carcinomas than in the adjacent non-malignant breast tissues (p<0.05). For all the other receptors, we could not measure any significant differences. 3,No significant correlations were observed between STS immunoreactivity and age, histological type and tumor stage. Furthermore, there was no correlation between STS expression and the expression of ER-α, ER-β, PR-A and PR-B. A positive association was however observed between STS and CDC47 (p < 0.05) and between STS and EST1E1 (p<0.05). As for STS, no significant correlation between EST1E1 immunoreactivity and clinicopathological parameters such as age, histological type and tumor stage could be observed. However, EST1E1 was positively correlated with CDC47 (p < 0.05), PR-B (p < 0.05) and particularly ER-β(p<0.005). There was no correlation between EST1E1 expression and PR-A or ER-α.Conclusions: 1,STS is overexpressed in carcinomas and associated with a high proliferation index. Controlling the STS overexpression could be a possible approach to decrease the hormone-dependent cancer growth; 2,We found the expression of EST1E1 were not only in the cytoplasm but also in the nuclear; 3,we have observed a positive association between two nuclear receptors, ER-βand PR-B, and the enzyme EST1E1. These new findings should lead to further investigations about the involvement of these receptors and their relation with protective enzyme in cancer growth and development.