Risk Factors The actual cause of this cancer is unknown Estrogen given estrogen alone as postmenopausal hormone replacement therapy Estrogen secreting tumors of the ovary are associated with an increased ncidence of endometrial carcinoma 2003-10-27 Carcinoma of the endometrium2003-10-27 Carcinoma of the Endometrium 4 Risk Factors The actual cause of this cancer is unknown． Estrogen given estrogen alone as postmenopausal hormone replacement therapy Estrogen secreting tumors of the ovary are associated with an increased incidence of endometrial carcinoma．