[The physiological function of human endometrium]

The cyclic change of human endometrial cells are controlled by the interaction between hypothalamus, pituitary gland and ovaries, thus making the endometrium proliferate, differentiate, exfoliate and then reproduce. The menstrual cycle is divided into three phases which are called follicle, ovulatory and luteal phase by the morphological change of the ovarium. The endometrial cycle is also classified to proliferative, secretory and menstrual phase. Estradiol (E2) stimulates the proliferation of endometrial cells by the indirect positive mechanism activated by the binding of E2 to E2 receptor. Growth factors (IGF- I, EGF, TGF- alpha etc.) induced by the transcription of the gene promote the proliferation of endometrial cells. Progesterone (P) has antagonistic effects on E2 actions and transform proliferative phase to secretory phase in endometrium. It is suggested that the possible mechanism of carcinogenesis of normal endometrium is the progression of endometrial hyperplasia due to the prolonged and unphysiological exposure to E2. The additional role of oncogenes (fos, fms, myc, myb, erb-B, neu) and growth factors on the mechanism of carcinogenesis of hyperplasia to cancer is very interested.