Estrogen exhibits a broad spectrum of physiologicalfunctions ranging from regulation of the menstrual cycleand reproduction to the modulation of bone density,brainfunction,and cholesterol mobilization.However,estrogenis also associated with pathological complications par-ticularly with the onset of gynaecological malignanciesincluding breast cancer and endometrial cancer;estrogenis now considered to be a classical etiological factor forbreast cancer and endometrial cancer.In the early 1970s,it was reported that there was a 20-35% increase in incidence of endometrial cancer in WesternCaucasian women who had undergone estrogen therapy[1].Subsequently,a variety of clinical and epidemiologi-cal investigations,with support from studies in cell cultureand animal models,have demonstrated the association ofestrogen with the development and/or progression of thedisease.In 2002,the US National Toxicology Programlisted steroidal estrogens as carcinogens for the first time.The report cites data from human epidemiologic studies thatshow an association between estrogen replacement therapyand an increase in the risk of endometrial cancer,as well asa less consistent increase in the risk of breast cancer. 相似文献