Clarification of Ki67 Expression in Association with the Histological Picture of Endometrium in Cases with Abnormal Uterine Bleeding in Nineveh Province

Background: Among the frequent daily challenges in the practice of gynecology are abnormal uterine bleeding (AUB) beside the distinction of fundamental endometrial lesions that stand behind it .Ki67 is among the excellent markers as the higher proliferation rate is one of the features of cancer cells. Aim: This study aims to clarify the expression of Ki67 in the endometrium of women suffering from abnormal uterine bleeding in Nineveh Province and to correlate its expression with the histological picture. Subjects, Materials, and Methods: This is a case series study that was enrolled analysis of data (retrospectively and prospectively) of 51 females who were presented with history of abnormal uterine bleeding and they were underwent an elective D&C and or hysterectomy after admission in several Hospitals, in Nineveh Province, Northern Iraq from 1 st January, 2020 to 30 th December, 2020. The selected paraffin blocks (n-=51) were cut into 3-4 micrometers thick sections and mounted on poly-L-lysine glass slides for immunohistochemical staining with using of positive and negative control sections at Unit of Immunohistochemistry in Vin Hospital -Duhok-North of Iraq. Staining was performe using the optimized protocol recommended by the International Ki67 in Breast Cancer Working Group together with Dako Autostainer according to manufacturer instructions. Results: This work revealed that 23(45%) out of 51 cases were aged >50 years. The highest mean of percentage of Ki67expression was in sections of proliferative endometrium. In fact, sections of 3/7 of cases which were exhibited a percentage of Ki67 expression from 76% to 100% aged >50 years, while sections of 3/7 of cases of menopause women showed percentage of Ki67 expression from 26% to 75 %. Further, 12 cases out of 17 showed an intensity of staining score of 2 were aged ˂50 years, while 3 out of 5 cases (which revealed an intensity of 3 ) were aged < 50 years. Five cases out of 17 which showed an intensity of staining score of 2 were aged >50 years, while 2 out of 5 cases which exhibited an intensity score of 3 were aged > 50 years. The current study showed that 11/16 cases of benign conditions presented with percentage of Ki67 expression of less than 25%,while 14/15 cases of endometrial hyperplasia presented with Ki67 expression of <25%. In contrary, 8 cases out of 20 of cases of endometrial adenocarcinoma showed Ki67 expression of >25%. Further, the intensity of Ki67 immunostaining of more than 2 was shown in 4 cases of endometrial adenocarcinoma. Regarding cases of endometrial hyperplasia, the current work revealed that 7 cases (46%) out of 15 cases were aged more than 50 years. About 4 cases (26%) of them are of atypical type with no significant differences between the percentage and intensity of Ki67 expression in cases of endometrial hyperplasia. In fact, 15 cases (75%) of endometrial adenocarcinoma were aged more than 50 years. Four (20%) of them were of grade 3, while six cases (30%) of them were of grade 2. According to the grade of endometrial adenocarcinoma, sections of 2 out of 5 cases of grade one (well differentiation) endometrial adenocarcinoma showed the percentage of Ki67 expression of more than 15%, while 5 out of 10 cases of grade 2 (Moderately differentiation) endometrial adenocarcinoma showed the percentage of Ki67 expression of more than 15%. Finally, 3 out of 5 cases of grade 3 (poorly differentiation) endometrial adenocarcinoma showed the percentage of Ki67 expression of more than 15%. About 5 cases out of 16 with Ki67 expression of more than 25%.Finally, 8 cases out of 20 cases of endometrial adenocarcinoma showed the Ki67 expression of more than 25%. Conclusion: Analysis of immunohistochemical expression of Ki67 in sections of women presented with AUB revealed that there is a relation with the age of patients. A significant association between expression of the Ki67 and poor tumor characteristics was conclude. Significant differences was shown between the expression of the Ki67 in sections of proliferative phase and those of endometrial hyperplasia ,while significant differences was found between the expression of the Ki67 in sections of endometrial hyperplasia Clarification of Ki67 Expression in .. Sura Atallah Mahmoud Al-Nuaimy Ann Coll Med Mosul December 2021 Vol. 43 No.2 177 and those of endometrial carcinoma. Using of Ki67 as diagnostic and prognostic tool in endometrial carcinoma may be conclude.