Background and Objective: Endometrial carcinoma is the most common gynaecologic malignancy in perimenopausal, and menopausal women. It is often preceded by endometrial hyperplasia. Estrogen appears to be involved in the development of endometrial carcinoma. Other mechanisms of endometrial carcinogenesis include mutations in
p53, PTEN, and proliferation markers like Ki-67. However, the pattern of Ki-67 expression is not well established in hyperplastic and neoplastic endometrium. Thus, objective of our study was to determine the immunohistochemical expression of Ki-67 in hyperplastic endometrium and endometrial carcinoma.

Methods: Immunohistochemical analysis of Ki-67 was done in 60 fixed, paraffin-embedded endometrial biopsy specimens and uterine resections obtained from patients. Specimens included simple hyperplasia, complex hyperplastic lesions, and endometrial adenocarcinoma.

Results: Ki-67 expression showed strong positivity in complex hyperplasia with atypia when compared to simple
hyperplasia, and complex hyperplasia without atypia. Though high grade endometrial carcinomas expressed more Ki-67 positivity, but there was no statistical significance found between expression of Ki-67 and tumour grading. Strong positivity was seen in advanced tumours with positive correlation between expression of Ki-67 and tumour stage.

Conclusion: Theexpression of Ki-67 may be used as diagnostic and prognostic marker in cases of endometrial carcinoma. Further studies with larger samples are needed to validate these findings.

Keywords: Endometrial Carcinoma; Immunohistochemistry; Ki-67.

Key Messages: Ki-67 expression was positive in 74.3% cases of endometrial hyperplasia. Statistical association  was observed between Ki-67 expression and simple hyperplasia, and between Ki-67 expression and complex hyperplasia with atypia. Ki-67 expression was positive in 80% cases of endometrial carcinoma. Statistical association was noted between tumor staging and Ki-67 exp