Immunohistochemical Study of Ki-67 in Hyperplastic and Endometrium Carcinoma: A Comparative Study

Endometrial hyperplasia is defined as a common clinical disorder caused by the increased levels of estrogens with low levels of progesterone; therefore, this hormonal imbalance leads to an increase in the proliferation rate of the endometrial cells. Endometrial carcinoma is one of the most important malignancies affecting women all over the world "accounting for 37.7% of all other disorders affecting the female reproductive system". The expression of the Ki-67 protein is related to the proliferative behavior of malignant tumor cell populations of their own, allowing it to be used as a marker of tumor aggressiveness. The present study was conducted to examine the expression of the proliferation marker, Ki-67 in various endometrial lesions. Ki-67 expression was evaluated in 60 endometrial samples that resulted as either endometrial curetting or hysterectomy specimens, diagnosed with simple hyperplasia (n=10), complex hyperplasia (n=20), atypical hyperplasia (n=6), and endometrial carcinoma (n=24). In patients with endometrial carcinoma, there was an increased expression of Ki-67, compared to proliferative endometrium and simple hyperplasia (P-value=0.0001). There was no such discrepancy between atypical hyperplasia and endometrial carcinoma cases. The expression of Ki-67 showed a positive association with the degree of endometrial cancer (P-value=0.0013), however, not with the age of the patients (P-value>0.05). There is a wide range of variations in the proliferation rate within the development of different endometrial lesions, including benign and malignant lesions. Our findings may be of value in differential diagnosis and prognosis of endometrial hyperplasia and endometrial carcinoma.