Dissociated Expression of Bcl-2 and Ki-67 in Endometrial Lesions: Diagnostic and Histogenetic Implications

Abstract

The objective of the present study was to analyze the expression of the proliferation marker, Ki-67, and the anti-apoptotic protein, bcl-2, in various endometrial lesions. Ki-67 and bcl-2 expressions were studied in 194 specimens of endometrial hyperplasia, polyps, carcinomas, and cyclic endometrium from a defined geographic area. Results were statistically analyzed with respect to marker expression, localization to the stromal or glandular component, and intraglandular topography. The lowest glandular Ki-67 expression was seen in secretory endometrium, in polyps, and in atypical hyperplasia. The Ki-67 score was significantly higher and less heterogeneous in endometrial carcinomas than in hyperplasia (p<0.001). Endometrial hyperplasia of all types was characterized by a markedly heterogeneous glandular expression of Ki-67. The glandular expression of bcl-2 was highest in proliferative endometrium and polyps. Bcl-2 expression was significantly lower in adenocarcinomas than in hyperplastic lesions (p=0.002). Ki-67 and bcl-2 expression showed a significant association in proliferative endometrium (p=0.003). Endometrial polyps demonstrated a unique pattern of very low expression of Ki-67 and high bcl-2 expression in both stroma and glands. Our findings indicate that an imbalance between proliferation and apoptosis may be an important factor in the development of different endometrial lesions, benign as well as malignant. The specific finding of inter- and intraglandular Ki-67 heterogeneity may be valuable as an adjunct to morphology in the differential diagnosis of endometrial hyperplasia.

Utility of Ki‐67, p53, Bcl‐2, and Cox‐2 biomarkers for low‐grade endometrial cancer and disordered proliferative/benign hyperplastic endometrium by imprint cytology

“…Proliferation is an important event in the cyclic endometrium and is measured by the expression of the proliferation marker Ki‐67 . We evaluated Ki‐67 expression in atrophic endometrium and different endometrial lesions.…”

Predicting the Coexistence of an Endometrial Adenocarcinoma in the Presence of Atypical Complex Hyperplasia: Immunohistochemical Analysis of Endometrial Samples

“…46,47 About 40% of the endometrioid adenocarcinomas show MIB-1 staining. 22,35 Some found significantly more staining in endometrial carcinomas compared with complex atypical hyperplasia, 21 where others found not. 31 In this study, the mean SI of MIB-1 in the group without a coexistent carcinoma was higher than the SI of the cases of ACH with a coexistent carcinoma.…”

Endometrial hyperplasia involving endometrial polyps: report of a series and discussion of the significance in an endometrial biopsy specimen

“…The exact pathogenesis of endometrial polyps is not fully elucidated, but they are thought to originate as a localised hyperplasia of the basalis, perhaps secondary to hormonal influences 15–18 . Tamoxifen administration is associated with an increased risk of development of endometrial polyps 19,20 .…”