Expression of Bcl-2 and Ki-67 in tamoxifen-associated endometrial polyps: Comparison with postmenopausal polyps

Background: The aim of this study was to evaluate the expression of Bcl-2 and Ki-67 in tamoxifen (TAM)-associated endometrial polyps and postmenopausal polyps. Material and Methods: For this purpose, a retrospective analysis of paraffin-embedded specimens was carried out. Polyps of 20 postmenopausal and 14 TAM-treated patients, 11 simple endometrial hyperplasia, 10 atypical complex endometrial hyperplasia and 8 endometrial adenocarcinoma specimens were included in the study. Hematoxylin/eosin-stained sections were evaluated. Immunohistochemical staining was performed to investigate the expression of Bcl-2 protein and the Ki-67 proliferation index. Results: There was no statistically significant difference between the 5 groups with regard to Bcl-2 staining (p > 0.05). However, Bcl-2 expression in TAM-associated polyps was higher (86%) than in the postmenopausal control group (80%). Positive Ki-67 was highest in the endometrial adenocarcinoma specimens, followed by the atypical complex endometrial hyperplasia group (p < 0.0001). Compared to these 2 groups, Ki-67 expression was lower in TAM-associated polyps, but Ki-67 indexes were significantly higher in the TAM-associated group than in the control group (p < 0.0001). Conclusion: Since TAM-associated polyps tend to have higher proliferation indexes and Ki-67 ratios than control groups, we suggest that they are likely to have a higher malignant potential.