Estrogen productivity of endometrium and endometrial cancer tissue; influence of aromatase on proliferation of endometrial cancer cells.

Abstract Aromatase, estrone (E 1 ) sulfatase and E 1 sulfotransferase activities were examined in endometrium and endometrial cancer tissue preparations. Aromatase and E 1 sulfatase activities in endometrial cancer tissues were found to be significantly higher than in normal endometrial tissues. However, E 1 sulfotransferase activity did not differ between benign and malignant tissue. We also examined the effect of testosterone (T) on aromatase activity and tritiated thymidine uptake (DNA synthesis) in various cultured cervical or corpus endometrial cancer cell lines (OMC-4, HHUA, Ishikawa, HEC-59). The results demonstrated that only the HEC-59 cell line had high aromatase activity and increased its DNA synthesis in response to T. This increase of DNA synthesis by T was not suppressed by simultaneous addition of cyproterone acetate, but was by tamoxifen. These data suggest that in situ estrogen production in endometrial cancer tissue is biologically important and that aromatase in cancer cells may contribute partially to cell proliferation if androgen substrate is provided.