Clinical significance of nucleostemin expression and its correlation with cyclin D1 expression in malignant ovarian tumors.

OBJECTIVE

To investigate the expression of the nucleostemin (NS) gene in ovarian tumors and its correlation with the expression of cyclin D1.

METHODS

The expression levels of nucleostemin and cyclin D1 proteins were measured by immunohistochemical staining in ovarian tumors and normal ovarian tissues, and the relationship between their levels was analyzed.

RESULTS

Nucleostemin gene and cyclin D1 expressions were detected in 28 and 27 specimens of malignant ovarian tumors (93.7% and 90.0%), 4 and 8 specimens of ovarian borderline tumors (40.0% and 80.0%), and in both specimens of benign ovarian tumors, respectively. The expression of NS gene was seen in 5, 13, and 10 specimens of malignant ovarian tumors of high, moderate, and low grade, respectively. The expression of the nucleostemin gene was significantly related to the tumor grade (r = 0.786, P < 0. 05), and a significant relationship between nucleostemin and cyclin D1 expression was found (r = 0.834, P < 0.05). The expression of the nucleostemin gene was not detected in normal ovarian tissue.

CONCLUSION

The expression of the nucleostemin gene in ovarian tumors is closely correlated with origination, progression, and grading of tumors and may serve as a marker in estimating the malignancy of ovarian tumors. The overexpression of cyclin D1 might be correlated with nucleostemin expression. Nucleostemin may have an impact on the passage of cells through the G1/S checkpoint, and thus cell cycle progress, by regulating cyclin D1 expression.