Increased expression of Nlp, a potential oncogene in ovarian cancer, and its implication in carcinogenesis

Objective: Nlp (Ninein-like protein), a novel centrosome protein involved in microtubule nucleation, has been studied extensively in our laboratory, and its overexpression has been found in some human tumors. To understand the role of Nlp in human ovarian Cancer development, we studied the correlation of Nlp expression with clinicopathological parameters and survival in epithelial ovarian Cancer, and the impact of Nlp overexpression on ovarian Cancer cells.

Methods: Nlp expression in normal, borderline, benign and malignant epithelial ovarian tissues was examined by immunohistochemistry. The correlation between Nlp expression and tumor grade, FIGO stage and histological type was also evaluated. Survival was calculated using Kaplan-Meier estimates. Cell proliferation and Apoptosis were assayed after stable transfection of pEGFP-C3-Nlp or empty vector in human ovarian Cancer cell line SKOV3.

Results: Nlp was positive in 1 of 10 (10%) normal ovarian tissues, 5 of 34 (14.7%) benign tumors, 9 of 26 (34.6%) borderline tumors and 73 of 131 (56.0%) ovarian tumors. Nlp immunoreactivity intensity significantly correlated with tumor grade, but not with FIGO stage or histological type. Kaplan-Meier curves showed that Nlp overexpression was marginally associated with decreased overall survival. Overexpression of Nlp enhanced proliferation and inhibited Apoptosis induced by paclitaxel in the SKOV3 cell line.

Conclusions: Overexpression of Nlp in ovarian tumors raises the possibility that Nlp may play a role in ovarian carcinogenesis.