Expression of cyclin D1 in normal, hyperplastic and neoplastic endometrium and its correlation with Ki-67 and clinicopathological variables.

Methods: We investigated cyclin D1 expression in proliferative endometrium, endometrial hyperplasia and endometrioid adenocarcinoma, and examined the correlation of cyclin D1 expression with Ki67 as a cell proliferation associated marker. Immunohistochemical expression of cyclin D1 and Ki67 were studied in 30 cases with endometrial carcinoma, 14 cases with atypical hyperplasia, 15 cases with simple hyperplasia and 30 cases with proliferative endometrium.

Results: One out of 30 patients (3.3%) with proliferative endometrium, 1 out of 14 patients (7.1%) with atypical hyperplasia, and 8 out of 30 patients (26.6%) with endometrial carcinoma were found to have immunoreactivity to cyclin D1. All cases of simple hyperplasia had negative staining for cyclin D1. A positive immunoreaction for Ki67 was obtained in all cases. Statistically significant difference was found in cyclin D1 immunoreactivity between both proliferative endometrium and adenocarcinoma, and simple hyperplasia and adenocarcinoma (p<0.05). In patients with adenocarcinoma, cyclin D1 immunoreactive cases had higher mean Ki67 values compared with the non-immunoreactive ones (p<0.05). Ki67 and cyclin D1 immunoreactivity had no impact on overall survival. Univariate analysis revealed a significant relationship between survival and grade and stage (p<0.01). Cyclin D1 expression was not correlated with age, depth of myometrial invasion, lymphovascular space involvement, grade, lymph node metastasis and stage.

Conclusion: Cyclin D1 expression in endometrial carcinoma is higher than proliferative endometrium and simple hyperplasia. These findings support that cyclin D1 may play a role in endometrial carcinogenesis.