Abstract: Objective To explore the role of estrogen in endometrial cancer by examining the expression of angiogenic factors in the estrogen-induced endometrial cell line HEC-1A. Method Real-time quantitative PCR and Western blots were used to analyze the mRNA and protein expression of angiogenic factors in HEC-1A cells after stimulation with estrogen for 30 min with or without 60-min pretreatment with inhibitors against the estrogen receptor，the AKT kinase pathway，and the NF-κB pathway. Result Real-time PCR and Western blots showed that mRNA and protein expression of angiogenic factors were significantly higher in the estrogen-stimulated group than in the unstimulated control group（P<0.05）. Pretreatment with signaling pathway inhibitors significantly reduced mRNA and protein expression of angiogenic factors below the levels in the estrogen-stimulated group that was not pretreated （P<0.05）. Conclusion Estrogen induces the production of angiogenic factors by activating signal transduction pathways.

Key words: Estrogen, Endometrial cancer, Angiogenic factors