Expression of the cell-cycle regulatory proteins (cyclins D1 and E) in endometrial carcinomas: correlations with hormone receptor status, proliferating indices, tumor suppressor gene products (p53, pRb), and clinicopathological parameters.

PURPOSE OF INVESTIGATION

This study aimed to investigate the immunohistochemical expression of cyclins D1 and E in normal, hyperplastic and neoplastic endometrium, and their correlation with proliferative activity and clinicopathological features.

METHODS

We carried out immunohistochemical techniques on archived material of formalin-fixed paraffin-embedded tissues using the antibodies against the cyclins D1 and E, PR-ER, p53, Ki67 (MIB1) and pRb with the streptavidin-biotin-peroxidase method in a total of 20 cases of normal endometrium, 32 cases of hyperplastic endometrium and 66 cases of endometrial carcinomas.

RESULTS

Cyclin D1 and E immunoreactivity was observed in the nuclei of tumour cells in 18.2% and 39.1%, respectively, of the cases of endometrial carcinomas. Cyclin D1 labelling index was not significantly correlated with any of the clinicopathologic parameters examined. However, there was a significant correlation between the cyclin E labelling index and histological grade of carcinoma (p = 0.00096), which increased significantly with histological grades of malignancy. We also detected a significant correlation between cyclin E and PCNA (p < 0.0001) as well as with the tumor suppressor genes p53 and pRb (p = 0.052 and 0.0002, respectively) in endometrioid endometrial carcinoma.

CONCLUSION

Our results indicate that cyclin E overexpression may be involved in the development and/or proliferation and differentiation of human endometrioid endometrial carcinoma. Immunoexpression of cyclin D1 does not appear to be associated with cell-cycle progression in the benign or malignant endometrium.